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RADIOSS Linear
Static and Normal Modes Analysis

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Trademark and Registered Trademark Acknowledgments
? ? ? Listed below are Altair HyperWorks applications. Copyright Altair Engineering Inc., All Rights Reserved for: ? ? HyperMesh 1990-2008; HyperCrash? 2001-2008; OptiStruct 1996-2008; RADIOSS? 1999-2008; ? ? ? ? HyperView 1999-2008; HyperView Player 2001-2008; HyperStudy 1999-2008; HyperStudy DSS 2002? ? ? 2008; HyperGraph 1995-2008; HyperGraph 3D 2005-2008; MotionView 1993-2008; MotionSolve? 2002? ? 2008; HyperForm 1998-2008; HyperXtrude 1999-2008; FEModel? 2004-2008; Process Manager? 20032008; HyperDieDynamics? 2007-2008; Templex? 1990-2008; Data Manager? 2005-2008; MediaView? 1999-2008; Batch Mesher? 2003-2008; TextView? 1996-2008; Manufacturing Solutions? 2005-2008.

All other trademarks and registered trademarks are the property of their respective owners.

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Table of Contents
Static and Normal Modes Analysis

RADIOSS Linear

Chapter 1: Introduction to RADIOSS...................................................................... 1
What is RADIOSS? .........................................................................................................1 Exercise 1.1: Hand editing the cards w/o a preprocessor ..............................................22 Exercise 1.2: Submitting jobs and reviewing the result files from RADIOSS ..................23 Exercise 1.3: Debugging models ...................................................................................24

Chapter 2: Interfacing with HyperMesh ............................................................... 27
What is HyperMesh? .....................................................................................................27 Exercise 2.1: Creating entities; materials, properties, components & BC.......................31 Exercise 2.2: Model organization...................................................................................35 Exercise 2.3: Submitting jobs from HyperMesh .............................................................37

Chapter 3: Linear Static Analysis ......................................................................... 39
Analysis Description ......................................................................................................39 Exercise 3.1: Bending and torsion of a channel bracket assembly.................................42 Exercise 3.2: Thermal stress analysis of a printed circuit board.....................................50

Chapter 4: Normal Modes Analysis...................................................................... 55
Analysis Description ......................................................................................................55 Exercise 4.1: Channel bracket assembly .......................................................................58 Exercise 4.2: Post-processing in HyperView.................................................................61 Exercise 4.3: Normal Modes Analysis of a Splash Shield ..............................................62 Exercise 4.4: Review the results using HyperView ........................................................68

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Chapter 5: Inertia Relief Analysis ......................................................................... 71
Analysis Description ...................................................................................................... 71 Exercise 5.1: Control Arm.............................................................................................. 74 Exercise 5.2: Post-processing in HyperView ................................................................ 80

Chapter 6: Buckling Analysis................................................................................ 83
Analysis Description ...................................................................................................... 83 Exercise 6.1: 3-D Buckling Analysis .............................................................................. 86 Exercise 6.2: Post-processing in HyperView ................................................................ 91

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Chapter 1: Introduction to RADIOSS

Chapter 1

Introduction to RADIOSS
What is RADIOSS?
Altair RADIOSS is a next-generation implicit and explicit finite-element solver for linear statics and dynamics as well as complex nonlinear transient dynamics and multi-body dynamics. This robust, multidisciplinary solution allows manufacturers to maximize durability, NVH, crash, safety, manufacturability and fluid-structure interaction performance in order to bring innovative products to market faster. In this chapter you will learn the basic understanding of the solver and its cards with an introduction to RADIOSS Linear. ? RADIOSS 9.0 is a new product that merges the analysis capabilities of the Altair’s non-linear finite element software RADIOSS, the linear finite element software OptiStruct, the one-step stamping software HyperForm Solver, and the multi-body dynamics software MotionSolve. RADIOSS 9.0 provides small and large displacement finite element, multi-body dynamics, and sheet metal stamping analysis. RADIOSS 9.0 offers a comprehensive analysis package. Many new developments compared to the previous versions RADIOSS 5.1, OptiStruct 8.0, HyperForm Solver 8.0, and MotionSolve 8.0 are included.

? ?

Exercises: Introduction to RADIOSS .......................................................................
Exercise 1.1: Hand editing the cards w/o a preprocessor .................................................. Exercise 1.2: Submitting jobs and reviewing the result files from RADIOSS ...................... Exercise 1.3: Debugging models

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RADIOSS Linear 1

Chapter 1: Introduction to RADIOSS

What is RADIOSS?
? Altair RADIOSS is a next-generation implicit and explicit finiteelement solver for linear statics and dynamics as well as complex nonlinear transient dynamics and multi-body dynamics. This robust, multidisciplinary solution allows manufacturers to maximize durability, NVH, crash, safety, manufacturability and fluid-structure interaction performance in order to bring innovative products to market faster.

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What is RADIOSS?

HyperMesh

HyperView HyperView Player

HyperViewPlayer HyperWeb HyperGraph HyperStudy HyperView MotionView OptiStruct MotionSolve HyperForm Altair RADIOSS HyperMesh
HyperStudy

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Chapter 1: Introduction to RADIOSS

What is RADIOSS Linear?
? RADIOSS Linear can perform the following Small Displacement FEA Implicit Solutions:
? ? ? ? ? ? ? ? ? ? Linear Static Normal Modes Inertia relief (Linear Static, Gap, Frequency and Transient response) Linear Buckling Composites Nonlinear Gap Frequency response (direct or modal) Random response Transient response (direct or modal) Heat Transfer

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RADIOSS Process
Pre-Processing in HyperMesh MODEL Nodes & Elements Materials Properties LOADS Moments Forces… CONSTRAINTS SPC, MPC Run Controls Subcases Output Requests…

Formatted ASCII input file Fem file RADIOSS Model Checks Solve

Binary result files H3d file Res file

Warnings, errors, run details Out file Log file

User requested Other ASCII result files

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RADIOSS Linear 3

Chapter 1: Introduction to RADIOSS

Consistent Units
? All internal calculations in RADIOSS are unit-less. ? It is the responsibility of the user to create the model using a consistent set of units. ? The equations that governs consistent units are:
? Force = Mass × Acceleration ? Mass = Density × Volume ? Acceleration = Length / Time2

? As an illustration:

Mass Length Young’s Modulus Kg Kg ton m mm mm Pa GPa MPa

Density Kg/m3 Kg/mm3

Force Stress N KN Pa GPa MPa

ton/mm3 N

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Element Quality Checks
? ? RADIOSS’s pre-processing phase incorporates element quality checks
? Prevents poorly discretized models

Element quality checks are performed in the following order:
1. Validity check of maximum allowable limits: ? ? 2. Based on mathematical limitations. Violations cause singular or illconditioned element matrices. Whether an element is in the acceptable range. Whether an element is in the recommended range. Violation may cause poor result quality, but will not prevent RADIOSS from running.

Quality check of error limits: ?

3.

Quality check of warning limits: ? ?

?

Violation of any check will skip the subsequent check(s).

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File Structure

Input Output Section

Case Control Section

Bulk Data Section

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Input Output Section

I/O Section

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Chapter 1: Introduction to RADIOSS

Input Output Section
? The I/O Options section controls: ? ? ? ? ? location and names of the input, output and scratch files, type of run (analysis, check or restart) overall running of the analysis or optimization, and, type, format and frequency of the output.

Some Categories of I/O Options: ? ? ? ? ? ? Output Format Controls: FORMAT, OUTPUT Run Controls: ANALYSIS, CHECK, CPU, NPROC, RESTART, SYSSSETTING File Names, Headers and Locations: EIGVNAME, INCLUDE, INFILE, LOADLIB, OUTFILE… Analysis Output: ACCELERATION, CSTRAIN, CSTRESS, DISPLACEMENT, ELFORCE… Optimization Output: DENSITY, DENSRES, DESHIS, HISOUT, PROPERTY, RESPRINT… Other Output Controllers: ECHO, ECHOON, ECHOOFF, DMIGNAME, MODEL…

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Input Output Section
? Illustration:
$ TITLE = RADIOSS Analysis SUBTITLE = Simulation $ ANALYSIS DISPLACEMENT(PUNCH) = ALL ECHO FORMAT H3D FORMAT HM STRAIN = ALL STRESS = ALL

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Case Control Section

Subcase Information Section

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Case Control Section
? The Case Control section ? ? ? ? identifies which loads and boundary conditions are to be used in a subcase, controls output type and frequency, and, may contain objective and constraint information for optimization problems.

Some categories of Subcase Information: ? ? ? ? ? General: LABEL, SUBCASE FE Analysis: B2GG, DLOAD, EIGVRETRIEVE, EIGVSAVE… MBD Analysis: INVEL, MBSIM, MLOAD, MOTION, SPC Optimization: DESGLB, DESOBJ, DESSUB… Component Mode Synthesis: CMSMETH, MPC

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Chapter 1: Introduction to RADIOSS

Case Control
? Subcases
? ? Used to combine loads and boundary conditions Allows multiple analyses to be performed in one solver run

? Individual subcases are defined using the SUBCASE statement ? Each subcase must have a unique Integer ID ? Illustration:
$$------------------------------------------------------------------------------$ $$ Case Control Cards $ $$------------------------------------------------------------------------------$ $ $HMNAME LOADSTEP 1"Test Loading" 1 $ SUBCASE 1 LABEL Test Loading SUBTITLE = Test 01 SPC = 1 LOAD = 2 $$------------------------------------------------------------------------------$
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Bulk Data Section

Bulk Data Section

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Bulk Data Section
? Comments and comment lines ? ? ? ? ? ? ? ? ? ? ? ? ? All characters after $ until the end of the line A line beginning with two slashes “//” or a pound “#” Must start from the first column They must be all caps and abbreviations are not allowed Examples: GRID, CQUAD4, PSHELL, MAT, LOAD, FORCE, SPC, … Must follow the parent entries If 1st character of any entry is either a blank, “+”, or “ * ”, it is treated as a continuation of the previous entry Content of 10th field in each card (with the exception of DTPG) and the 1st field in each continuation card is disregarded Do not have to be in the same format as the parent entries Blanks preceding and following an entry are ignored ? Keyword entry is the exception: must be left justified in its field

Keywords

Continuation cards

Each entry can be placed anywhere within the field

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Bulk Data Section
? The Bulk Data section ? begins with the BEGIN BULK statement ? ends with the END DATA statement ? Data lines can contain a maximum of 80 characters ? Characters after the 80th are ignored ? Each line of data contains up to nine fields in one of the three accepted formats: ? Fixed Format ? Free Format
GRID, 1, , 24.0, 24.0, 0.0

? Large Field Format

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Chapter 1: Introduction to RADIOSS

Bulk Data Section
? Character entries
? ? ? ? Must start with a letter Can not contain blanks within the data Longer than 8 characters are truncated in large field and free field formats ? Exception: file names on the INCLUDE card Case insensitive (except user-provided labels)

?

Numeric entries
? ? ? ? Must start with a digit, ‘+’ or ‘-’ Integer entries may not contain a decimal point or an exponent part Integer data placed in the field reserved for real valued data is accepted and converted to a double precision Real must have a decimal can follow most formats within defined characters format

Example FORCE FORCE ? SID Integer 6 G Integer 13 CID Integer 0 F Real -2.93 N1 Real 0.0

Invisible tab characters are equivalent to the number of spaces needed to advance to the nearest tab stop ? Tab stops are placed at the beginning of each eight-character field

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Bulk Data Section
Some categories of Bulk Data are:
BEGIN BULK PARAM,AUTOSPC,YES PARAM,CHECKEL,YES $ SYSTEM Data CORD2R 1 20.0 -20.0 0.0 20.0 -20.0 -100.0 + -80.0 -20.0 0.0 $ GRID 1 50.0 -50.0 0.0 GRID 2 50.0 -40.0 0.0 $ CBAR 101 1 94 550.0 1.0 0.0 $ CQUAD4 1 1 55 58 59 54 CQUAD4 2 1 54 59 50 51 CQUAD4 3 1 58 43 44 59 $ PSHELL 1 11.0 1 1 0.0 $ PBEAM 1 178.53975490.8734490.87340.0 981.7469 $ MAT1 1210000.0 0.3 7.90E-09 $ EIGRL 3 20 MASS $ FORCE 2 11 01.0 0.0 0.0 -100.0 $ SPC 1 31 1234560.0 ENDDATA Altair Proprietary and Confidential Information

Nodes

Elements

Systems

Forces
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Bulk Data Section PARAM cards
BEGIN BULK PARAM,AUTOSPC,YES PARAM,CHECKEL,YES $ SYSTEM Data CORD2R 1 20.0 -20.0 0.0 20.0 -20.0 -100.0 + -80.0 -20.0 0.0 $ GRID 1 50.0 -50.0 0.0 GRID 2 50.0 -40.0 0.0 $ CBAR 101 1 94 550.0 1.0 0.0 $ CQUAD4 1 1 55 58 59 54 CQUAD4 2 1 54 59 50 51 CQUAD4 3 1 58 43 44 59 $ PSHELL 1 11.0 1 1 0.0 $ PBEAM 1 178.53975490.8734490.87340.0 981.7469 $ MAT1 1210000.0 0.3 7.90E-09 $ EIGRL 3 20 MASS $ FORCE 2 11 01.0 0.0 0.0 -100.0 $ SPC 1 31 1234560.0 ENDDATA Altair Proprietary and Confidential Information

? PARAM cards define parameters used during the analysis. ? Some examples of parameter cards are:
? ALMS, AUTOSPC, CHECKEL, CHECKMAT, INREL, PRGPST, WTMASS

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Bulk Data Section PARAM cards
? Example parameter (PARAM card):
(1) PARAM (2) N (3) V (4) (5) (6) (7) (8) (9) (10)

Where:
N V Name of Parameter Value of Parameter

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Chapter 1: Introduction to RADIOSS

Bulk Data Section Local Coordinate Systems
BEGIN BULK PARAM,AUTOSPC,YES PARAM,CHECKEL,YES $ SYSTEM Data CORD2R 1 20.0 -20.0 0.0 20.0 -20.0 -100.0 + -80.0 -20.0 0.0 $ GRID 1 50.0 -50.0 0.0 GRID 2 50.0 -40.0 0.0 $ CBAR 101 1 94 550.0 1.0 0.0 $ CQUAD4 1 1 55 58 59 54 CQUAD4 2 1 54 59 50 51 CQUAD4 3 1 58 43 44 59 $ PSHELL 1 11.0 1 1 0.0 $ PBEAM 1 178.53975490.8734490.87340.0 981.7469 $ MAT1 1210000.0 0.3 7.90E-09 $ EIGRL 3 20 MASS $ FORCE 2 11 01.0 0.0 0.0 -100.0 $ SPC 1 31 1234560.0 ENDDATA Altair Proprietary and Confidential Information

?

A Local Coordinate System is a coordinate system whose location and/or orientation is different from the global coordinate system. Local coordinate systems can be used to define: ? ? Location of Nodes, Orientation of nodes, elements, materials, Loads, constraints, and Results.

?

?

You can create the following types of Local Coordinate systems: ? ? ? Rectangular Cylindrical Spherical

?

You need the definition of three noncollinear points to define a Local Coordinate systems.
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Bulk Data Section Local Coordinate Systems
? Example local coordinate system (CORD2R card):
(1) CORD2R + (2) CID C1 (3) RID C2 (4) A1 C3 (5) A2 (6) A3 (7) B1 (8) B2 (9) B3 (10)

Where:
CID RID A1,A2,A3 B1,B2,B3 C1,C2,C3 Coordinates of three points in the basic/global coordinate system Unique coordinate system identification number. (Integer > 0) Identification number of a coordinate system that is defined independently from this coordinate system (Optional, Default = 0, Integer)

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Bulk Data section GRIDs
BEGIN BULK PARAM,AUTOSPC,YES PARAM,CHECKEL,YES $ SYSTEM Data CORD2R 1 20.0 -20.0 0.0 20.0 -20.0 -100.0 + -80.0 -20.0 0.0 $ GRID 1 50.0 -50.0 0.0 GRID 2 50.0 -40.0 0.0 $ CBAR 101 1 94 550.0 1.0 0.0 $ CQUAD4 1 1 55 58 59 54 CQUAD4 2 1 54 59 50 51 CQUAD4 3 1 58 43 44 59 $ PSHELL 1 11.0 1 1 0.0 $ PBEAM 1 178.53975490.8734490.87340.0 981.7469 $ MAT1 1210000.0 0.3 7.90E-09 $ EIGRL 3 20 MASS $ FORCE 2 11 01.0 0.0 0.0 -100.0 $ SPC 1 31 1234560.0 ENDDATA Altair Proprietary and Confidential Information

? GRIDs (or “nodes”) are locations in space ? Used to define the structural model and its boundary conditions

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Bulk Data section GRIDs
? Example node (GRID card):
(1) GRID (2) ID (3) CP (4) X1 (5) X2 (6) X3 (7) CD (8) PS (9) (10)

Where:
ID CP X1,X2,X3 CD Unique grid point identification number. (Integer > 0) Identification number of coordinate system in which the location of the grid point is defined. (Integer > 0 or blank) Location of the grid point in coordinate system CP Identification number of coordinate system in which the displacements, degrees of freedom, constraints, and solution vectors are defined at grid point. (Integer > 0 or blank) Permanent single-point constraints associated with grid point. Up to six unique digits may be placed in the field with no imbedded blanks. (Integer > 0 or blank)

PS

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Chapter 1: Introduction to RADIOSS

Bulk Data section Elements
BEGIN BULK PARAM,AUTOSPC,YES PARAM,CHECKEL,YES $ SYSTEM Data CORD2R 1 20.0 -20.0 0.0 20.0 -20.0 -100.0 + -80.0 -20.0 0.0 $ GRID 1 50.0 -50.0 0.0 GRID 2 50.0 -40.0 0.0 $ CBAR 101 1 94 550.0 1.0 0.0 $ CQUAD4 1 1 55 58 59 54 CQUAD4 2 1 54 59 50 51 CQUAD4 3 1 58 43 44 59 $ PSHELL 1 11.0 1 1 0.0 $ PBEAM 1 178.53975490.8734490.87340.0 981.7469 $ MAT1 1210000.0 0.3 7.90E-09 $ EIGRL 3 20 MASS $ FORCE 2 11 01.0 0.0 0.0 -100.0 $ SPC 1 31 1234560.0 ENDDATA Altair Proprietary and Confidential Information

ELEMENTS The geometry of the structure is modeled using Elements:

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Bulk Data section Elements
BEGIN BULK PARAM,AUTOSPC,YES PARAM,CHECKEL,YES $ SYSTEM Data CORD2R 1 20.0 -20.0 0.0 20.0 -20.0 -100.0 + -80.0 -20.0 0.0 $ GRID 1 50.0 -50.0 0.0 GRID 2 50.0 -40.0 0.0 $ CBAR 101 1 94 550.0 1.0 0.0 $ CQUAD4 1 1 55 58 59 54 CQUAD4 2 1 54 59 50 51 CQUAD4 3 1 58 43 44 59 $ PSHELL 1 11.0 1 1 0.0 $ PBEAM 1 178.53975490.8734490.87340.0 981.7469 $ MAT1 1210000.0 0.3 7.90E-09 $ EIGRL 3 20 MASS $ FORCE 2 11 01.0 0.0 0.0 -100.0 $ SPC 1 31 1234560.0 ENDDATA Altair Proprietary and Confidential Information

? A few of the available elements are:
? 3D: CHEXA, CPENTA, CPYRA, CTETRA ? 2D: CQUAD8, CQUAD4, CTRIA6, CTRIA3, CSHEAR ? 1D: CBEAM, CELAS2, CGAP, PLOTEL, RBE2, RBE3… ? 0D: CONM2…

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Bulk Data section Elements
? Example element (CQUAD4 card):
(1) CQUAD4 (2) EID (3) PID (4) G1 (5) G2 (6) G3 (7) G4 (8) (9) (10)

EID

Unique element identification number Identification number of a PSHELL or PCOMP property entry Grid ID’s of connection points. (Integers > 0, all unique)

Where:

PID

G1,G2,G3,G4

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Bulk Data section Properties
BEGIN BULK PARAM,AUTOSPC,YES PARAM,CHECKEL,YES $ SYSTEM Data CORD2R 1 20.0 -20.0 0.0 20.0 -20.0 -100.0 + -80.0 -20.0 0.0 $ GRID 1 50.0 -50.0 0.0 GRID 2 50.0 -40.0 0.0 $ CBAR 101 1 94 550.0 1.0 0.0 $ CQUAD4 1 1 55 58 59 54 CQUAD4 2 1 54 59 50 51 CQUAD4 3 1 58 43 44 59 $ PSHELL 1 11.0 1 1 0.0 $ PBEAM 1 178.53975490.8734490.87340.0 981.7469 $ MAT1 1210000.0 0.3 7.90E-09 $ EIGRL 3 20 MASS $ FORCE 2 11 01.0 0.0 0.0 -100.0 $ SPC 1 31 1234560.0 ENDDATA Altair Proprietary and Confidential Information

? Property cards are used to define element attributes like:
? Element thickness ? ID of the Material being used ? Section properties for beams…

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Chapter 1: Introduction to RADIOSS

Bulk Data section Properties
? Example property (PSHELL card):
(1) PSHELL (2) PID (3) MID1 (4) T (5) MID2 (6) 12I/T3 (7) MID3 (8) TS/T (9) NSM (10)

PID

Unique shell element property identification number. (Integer > 0) Material identification number for membrane. (Integer > 0) Default value for the membrane thickness Material identification number for bending Bending stiffness parameter. (default = 1.0) Material identification number for transverse shear Transverse shear thickness divided by the membrane thickness. (default = 0.833333) Nonstructural mass per unit area
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Where:

MID1 T MID2

12I/T3 MID3 TS/T NSM

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Bulk Data section Properties
? Property cards are referenced by elements:
? CHEXA, CPENTA, CPYRA, CTETRA ? CQUAD8, CQUAD4, CTRIA6, CTRIA3 ? CSHEAR ? CBEAM PSHEAR PBEAM PSOLID PSHELL or PCOMP

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Bulk Data section Materials
BEGIN BULK PARAM,AUTOSPC,YES PARAM,CHECKEL,YES $ SYSTEM Data CORD2R 1 20.0 -20.0 0.0 20.0 -20.0 -100.0 + -80.0 -20.0 0.0 $ GRID 1 50.0 -50.0 0.0 GRID 2 50.0 -40.0 0.0 $ CBAR 101 1 94 550.0 1.0 0.0 $ CQUAD4 1 1 55 58 59 54 CQUAD4 2 1 54 59 50 51 CQUAD4 3 1 58 43 44 59 $ PSHELL 1 11.0 1 1 0.0 $ PBEAM 1 178.53975490.8734490.87340.0 981.7469 $ MAT1 1210000.0 0.3 7.90E-09 $ EIGRL 3 20 MASS $ FORCE 2 11 01.0 0.0 0.0 -100.0 $ SPC 1 31 1234560.0 ENDDATA Altair Proprietary and Confidential Information

? There are 8 material types available. ? Linear temperature independent: ? MAT1: isotropic ? MAT2: anisotropic (for 2D elements) ? MAT8: orthotropic (for 2D elements) ? MAT9: anisotropic (for 3D elements), ? Temperature dependent: ? defined with the respective MAT cards ? MATT1, MATT2, MATT8 and MATT9.

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Bulk Data section Materials
? Example material card (MAT1):
(2) MID (3) E (4) G (5) NU (6) RHO (7) A (8) TREF (9) GE (10)

(1) MAT1

MID

Unique material identification number (Integer > 0) Young’s Modulus Shear Modulus Poisson’s Ratio Mass density Thermal expansion coefficient Reference temperature for thermal loading Structural Element Damping coefficient
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Where:

E G NU

RHO A TREF GE

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Chapter 1: Introduction to RADIOSS

Bulk Data Section Materials

? Material cards are referenced by property cards.

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Bulk Data section Materials
? Looking at the connectivity:

NODES

ELEMENT

PROPERTY

MATERIAL

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Chapter 1: Introduction to RADIOSS

Bulk Data section Loads and Boundary Conditions
BEGIN BULK PARAM,AUTOSPC,YES PARAM,CHECKEL,YES $ SYSTEM Data CORD2R 1 20.0 -20.0 0.0 20.0 -20.0 -100.0 + -80.0 -20.0 0.0 $ GRID 1 50.0 -50.0 0.0 GRID 2 50.0 -40.0 0.0 $ CBAR 101 1 94 550.0 1.0 0.0 $ CQUAD4 1 1 55 58 59 54 CQUAD4 2 1 54 59 50 51 CQUAD4 3 1 58 43 44 59 $ PSHELL 1 11.0 1 1 0.0 $ PBEAM 1 178.53975490.8734490.87340.0 981.7469 $ MAT1 1210000.0 0.3 7.90E-09 $ EIGRL 3 20 MASS $ FORCE 2 11 01.0 0.0 0.0 -100.0 $ SPC 1 31 1234560.0 ENDDATA Altair Proprietary and Confidential Information

After the geometry and material of a structure are defined, loads and boundary conditions need to be applied. These differ depending on the desired solution sequence.

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Bulk Data section Normal Modes
BEGIN BULK PARAM,AUTOSPC,YES PARAM,CHECKEL,YES $ SYSTEM Data CORD2R 1 20.0 -20.0 0.0 20.0 -20.0 -100.0 + -80.0 -20.0 0.0 $ GRID 1 50.0 -50.0 0.0 GRID 2 50.0 -40.0 0.0 $ CBAR 101 1 94 550.0 1.0 0.0 $ CQUAD4 1 1 55 58 59 54 CQUAD4 2 1 54 59 50 51 CQUAD4 3 1 58 43 44 59 $ PSHELL 1 11.0 1 1 0.0 $ PBEAM 1 178.53975490.8734490.87340.0 981.7469 $ MAT1 1210000.0 0.3 7.90E-09 $ EIGRL 3 20 MASS $ FORCE 2 11 01.0 0.0 0.0 -100.0 $ SPC 1 31 1234560.0 ENDDATA Altair Proprietary and Confidential Information

? For normal modes analysis, a number of frequencies or a frequency range is required. ? For linear buckling analysis, a number of eigenvalues or an eigenvalue range is required. ? Both requirements are met through the use of the real eigenvalue extraction (EIGRL) card.

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RADIOSS Linear 19

Chapter 1: Introduction to RADIOSS

Bulk Data section Loads and Boundary Conditions
BEGIN BULK PARAM,AUTOSPC,YES PARAM,CHECKEL,YES $ SYSTEM Data CORD2R 1 20.0 -20.0 0.0 20.0 -20.0 -100.0 + -80.0 -20.0 0.0 $ GRID 1 50.0 -50.0 0.0 GRID 2 50.0 -40.0 0.0 $ CBAR 101 1 94 550.0 1.0 0.0 $ CQUAD4 1 1 55 58 59 54 CQUAD4 2 1 54 59 50 51 CQUAD4 3 1 58 43 44 59 $ PSHELL 1 11.0 1 1 0.0 $ PBEAM 1 178.53975490.8734490.87340.0 981.7469 $ MAT1 1210000.0 0.3 7.90E-09 $ EIGRL 3 20 MASS $ FORCE 2 11 01.0 0.0 0.0 -100.0 $ SPC 1 31 1234560.0 ENDDATA Altair Proprietary and Confidential Information

Static loads can be applied in the form of ? point forces (FORCE, FORCE1), ? gravity loads (GRAV), ? moments (MOMENT, MOMENT1), ? pressures (PLOAD, PLOAD1, PLOAD2, PLOAD4), ? rotational forces (RFORCE), ? enforced displacements (SPCD), and ? temperature gradients (TEMP, TEMPD).

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Bulk Data section Loads and Boundary Conditions
? Example load (FORCE card):
(1) FORCE (2) SID (3) G (4) CID (5) F (6) N1 (7) N2 (8) N3 (9) (10)

Where:
SID G CID F Load set identification number. (Integer > 0) Grid point identification number. (Integer > 0) Coordinate system identification number. Default = 0 (Integer > 0, or blank) Scale factor Components of vector measured in coordinate system defined by CID. (must have at least one non-zero component)

N1,N2,N3

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HyperWorks 9.0

Chapter 1: Introduction to RADIOSS

Bulk Data section Loads and Boundary Conditions
BEGIN BULK PARAM,AUTOSPC,YES PARAM,CHECKEL,YES $ SYSTEM Data CORD2R 1 20.0 -20.0 0.0 20.0 -20.0 -100.0 + -80.0 -20.0 0.0 $ GRID 1 50.0 -50.0 0.0 GRID 2 50.0 -40.0 0.0 $ CBAR 101 1 94 550.0 1.0 0.0 $ CQUAD4 1 1 55 58 59 54 CQUAD4 2 1 54 59 50 51 CQUAD4 3 1 58 43 44 59 $ PSHELL 1 11.0 1 1 0.0 $ PBEAM 1 178.53975490.8734490.87340.0 981.7469 $ MAT1 1210000.0 0.3 7.90E-09 $ EIGRL 3 20 MASS $ FORCE 2 11 01.0 0.0 0.0 -100.0 $ SPC 1 31 1234560.0 ENDDATA Altair Proprietary and Confidential Information

? RADIOSS allows the following boundary conditions to be applied at nodal locations on the structure: ? single-point constraint (SPC, SPC1), ? multi-point constraint (MPC), and ? fictitious support (SUPORT, SUPORT1).

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Bulk Data section Loads and Boundary Conditions
?
(1) SPC

Example constraint (SPC card):
(2) SID (3) G (4) C (5) D (6) G (7) C (8) D (9) (10)

Where:
SID G C Identification number of single-point constraint set. (Integer > 0) Grid or scalar point identification number. (Integer > 0) Component numbers. Scalar points: Integer, zero or blank Grid points: D Up to six unique digits (0 thru 6) with no embedded blanks

Value of enforced displacement for all coordinates designated by G and C

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RADIOSS Linear 21

Chapter 1: Introduction to RADIOSS

Exercise 1.1: Hand editing the cards w/o a preprocessor
Purpose
In this exercise, we gain an understanding of the basic concepts for creating a RADIOSS input file with a text editor. More specifically, we learn how to create or edit these entities node (GRID), element (CQUAD), material (MAT1), SPC (SPC), FORCE (FORCE) and a Subcase (SUBCASE) and review all of these in HyperMesh.

Exercise 1.1:
Step 1: Hand editing the cards w/o a preprocessor
1. Open Start_model.fem in a text editor also import the file in HM. (The teacher will walk through how to do this.) 2. Save the file in your working directory. 3. Review the GRID cards in the text editor and create a GRID with ID 3 and these coordinates X=5.0, Y=15.0 & Z=0.0. 4. Review the CQUAD elements in the test editor and create CQUAD element ID 4 pointing to PSHELL property 1 using GRIDs 8, 10, 6 & 3. Import in HM and review. 5. Edit MAT1 ID 1 material with E = 210000.0 & P = 0.3. Review in the text editor what property points to this material. 6. Create a SPC @ node 5 with constraints in 1-6. Import in HM and review. 7. Create FORCE @ node 3 with a magnitude of 10 in the positive Z direction. 8. Create a SUBCASE in the case control with SPC = 1 & FORCE = 2. 9. Save the file in your working directory

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HyperWorks 9.0

Chapter 1: Introduction to RADIOSS

Exercise 1.2: Submitting jobs through the GUI
Purpose
In this exercise, you learn how to run a job using the RADIOSS/OptiStruct GUI and how to review results in HV along with the teacher.

Exercise 1.2:
Step 1: Submitting jobs through the GUI
1. Go to: Start All Programs Altair HyperWorks 9.0 OptiStruct

2. Click Browse… after the Input file: field and select the input file Start_model.fem. 3. Click Run to run the analysis.

Step 2: Reviewing the results from RADIOSS in HV
1. Go to: Start All Programs Altair HyperWorks 9.0 HyperView 2. Work along with teacher

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RADIOSS Linear 23

Chapter 1: Introduction to RADIOSS

Exercise 1.3: Debugging models
Purpose
In this exercise, we gain an understanding of the basic concepts for debugging a model. More specifically, learn where to look for more detailed about the analysis and any errors that might occur in the .out file.

Exercise 1.3:
Step 1: Run the fem file in RADIOSS/OptiStruct
1. Copy debug_edit.fem to your working directory 2. Go to: Start All Programs Altair HyperWorks 9.0 OptiStruct

3. Click Browse… after the Input file: filed and search for the file debug_edit.fem from your working directory. 4. Run the analysis. The analysis should give an error message similar to that shown below.

Step 2: Open the .out file and find the error.
1. Open the debug_edit.out file in a text editor.

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Chapter 1: Introduction to RADIOSS

2. Search for the string ERROR.

In this case the error is due to elements not having a property definition. To fix this you must assign a property to your components or elements.

Step 3: Fix the elements that do not have properties in a text editor.
1. Open debug_edit.fem file in a text editor. 2. Edit all elements so that they point to property ID 1. (It is easiest to do this in HM.) 3. Re-run the job through the GUI.

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Chapter 1: Introduction to RADIOSS

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HyperWorks 9.0

Chapter 2: Interfacing with HyperMesh

Chapter 2

Interfacing with HyperMesh
Using HM to interface with RADIOSS Linear
This chapter gives you an understanding of the basic concepts for creating RADIOSS input files in HM. More specifically, you will learn how to create, review and edit entities in HyperMesh to see how they will appear in the solver input file, create materials and properties and select solver element types for HyperMesh element configurations. RADIOSS can solve for various combinations of boundary conditions on your models defining many different types of analysis. The loads can be in the form of constraints, forces, pressures, temperatures, etc.

Exercises: Interfacing with HyperMesh ...................................................................
Exercise 2.1: Creating entities; materials, properties, components & BC........................... Exercise 2.2: Model organization....................................................................................... Exercise 2.3: Submitting jobs from HyperMesh .................................................................

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RADIOSS Linear 27

Chapter 2: Interfacing with HyperMesh

Interfacing with HyperMesh
? HM is a “solver neutral” pre-processor ? ? ? ? Works with many different solvers Can convert between supported solvers Capable of assembly from input files of different solvers Can be customized to support other solver codes

?

Definition of all information for an analysis besides the mesh ? ? ? ? ? Specification of solver to be used Creation materials, properties, etc. Assignment of a solver specific format to HyperMesh entities Creation of boundary conditions (constraints, loads, contacts, etc.) Definition of other required information (solution requests, general run parameters, etc.)

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Interfacing with HyperMesh
? Preferences > User Profiles > RADIOSS ? Loads the appropriate template ? Template can also be set manually – Preferences > Global – Files panel > template

?

Sets the files > import > fe sub-panel to RADIOSS

?

Loads the Utility menu with tools specific to working with RADIOSS

?

Customizes the HyperMesh menu for RADIOSS ? ? ? Removes panels that are not used Removes controls inside a panel that are not used Renames some panels & controls in panels to match RADIOSS terminology
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HyperWorks 9.0

Chapter 2: Interfacing with HyperMesh

Interfacing with HyperMesh
? Model browser ? View collectors and assemblies in a hierarchical tree format ? Create, delete, and rename collectors ? Edit collector attributes ? Organize collectors into assemblies ? Drag and drop

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Interfacing with HyperMesh
? Solver Browser
? Displays RADIOSS based cards in a tree format ? Uses organization & structure of RADIOSS ? Performs basic actions involving cards
? Create new cards ? Delete existing cards ? Edit attributes of existing cards

? Solver Browser can be found in the View pulldown menu

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RADIOSS Linear 29

Chapter 2: Interfacing with HyperMesh

Interfacing with HyperMesh
? Use the Collectors panel card images. on the toolbar to Create/Update collectors and their

? Use the Card Editor panel

on the toolbar to View/Edit card images.

? Use the Element types panel (1D/2D/3D pages) to create the right type of elements.

? Use the Load types panel (Analysis page) to create the right type of loads.

? Use the HyperBeam module to create beam section properties.

? Group your loads and constraints into subcases using either ? Subcase panel (Analysis page) –Or– ? Load Steps Browser (FEA page of Utility menu)
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HyperWorks 9.0

Chapter 2: Interfacing with HyperMesh

Exercise 2.1: Creating materials, properties & BC’s in HM
Purpose
This exercise uses the file channel_brkt_assem2.hm. It contains the bracket and channel assembly pictured below. Begin setting up the model for a RADIOSS analysis for the linear static response of the assembly to forces on it. You will need to define materials and properties and connect the channel to the bracket.

Exercise 2.1:
Step 1: Launch HM, set the user profile and retrieve the HyperMesh model file channel_brkt_assem2.hm.
1. Go to: Start All Programs Altair HyperWorks “version” HyperMesh
When the app is launched a GUI window will show up wanting you to select a user profile.

2. Select the RADIOSS radio button on the left then select BulkData from list to the right in the User Profile dialog. 3. Open channel_brkt_assem2.hm in HyperMesh. The user profile can also be set or changed from the Preferences pulldown menu by selecting User Profiles…

Step 2: Create 2 material collectors steel & aluminum 2 different ways. First way
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RADIOSS Linear 31

Chapter 2: Interfacing with HyperMesh

1. Go to the Model browser tab. 2. Right-click in the white space of the browser list. 3. Select Create >> Material. 4. The Create Material popup dialog appears. 5. In the field next to Name: enter steel. 6. Change the color if you wish by clicking Color:. 7. Click on the Card image: field “none”. 8. Select MAT1 from the popup list. 9. Click Create/Edit. 10. Click [E] [Nu] and [RHO] Notice that default values appear for Steel properties in this panel only. There is no other material information in the database. 11. Click return.

Second way
1. On the Collectors toolbar, go to the Material Collector panel ( 2. In the field next to mat name = enter aluminum. 3. Click card image = and set to MAT1. 4. Click Create/Edit to create the material and edit it. The card image for the new material appears. 5. Click [E] and enter 7.0e4 in the field that appears. This is Young’s Modulus. 6. Click [NU] and enter 0.33 in the field that appears. This is Poisson' Ratio. s 7. Click return to exit the panel. 8. Click return again to exit out of Material Collectors panel. ).

Step 3: Create a Property collector (PSHELL card image)
1. On the Collectors toolbar, go to the Property Collector panel ( 2. Go to the create sub-panel using the radio buttons at the left. 3. In the prop name= field enter channel. 4. Click the type= button and select 2D. 5. Click the card image= button and pick PSHELL. 6. Click the material= button and select the aluminum material collector.
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).

HyperWorks 9.0

Chapter 2: Interfacing with HyperMesh

7. Click the green create/edit button (This will open the card editor panel). 8. Click [T] and enter 3.0 into the field that appears. (This will assign a 3.0 unit thickness). 9. Click Return twice to go to the main menu.

Step 4: Create 2 load collectors spc, bending 2 different ways. First way
1. Go to the Model browser tab. 2. Right-click in the white space of the browser list. 3. Select Create >> LoadCollector. 4. In the filed next to Name: enter spc. 5. Change the color if you wish by clicking Color:. 6. Click create. 7. From the Analysis page enter the constraints panel. 8. Click on nodes. 9. Select on plane. 10. Select any 3 nodes on the lower portion of the channel bracket to select the plane similar to as shown below.

11. Click select entities. 12. Leave dof1 through dof6 checked. 13. Click create. 14. Click return.

Second way
1. On the Collectors toolbar, go to the Load Collector panel ( 2. In the field next to loadcol name = enter bending. ).

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RADIOSS Linear 33

Chapter 2: Interfacing with HyperMesh

3. Click color to change the color if you wish. 4. Click on the toggle beside card image = and select no card image. 5. Click create to create the Load Collector. 6. Click return. 7. From the Analysis page enter the force panel. 8. Select some nodes on the edge of the bracket as shown below.

9. Click on magnitude = and enter 1000. 10. Toggle N1, N2 & N3 to y-axis. 11. Click create. If you can not see the force you can scale the visual display of it by increasing the uniform size value. Note: We have created 2 load collectors but only the last one is active. All boundary conditions created from this point will be placed in the bending load collector. To change the active load collector you can click on “bending” in the lower right corner of the app or click “g” on the keyboard then click “bending”.

Step 5 Save the Hypermesh file
1. Select File from the pull-down menu. 2. Click on Save as… A Save file… window dialog opens. 3. Type in channel_brkt_assem2_complete.hm and click Save.

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Chapter 2: Interfacing with HyperMesh

Exercise 2.2: Model organization in HM
Purpose
This exercise uses the file channel_model_org.hm or you can continue from exercise 2.1. This exercise assumes you now have created all your materials, properties and components.

Exercise 2.2:
Step 1: Assign the channel property to the channel component.
1. On the collectors toolbar, go to the Components panel ( ).

2. Go to the assign sub-panel. (This panel can also be accessed directly by using the pulldown menu select Collectors >> Assign >> Component Property.) 3. Select comps >> channel. 4. Click select to complete the selection. 5. For property= select channel. 6. Click assign. 7. Do the same steps for the aluminum bracket. 8. Click return to exit the panel.

Step 2: Update the bracket property to have a PSHELL card image, a thickness of 2.0, and the aluminum material.
1. Access the properties update panel in one of the following ways: ? ? From the Pull-down menu, select Properties, then Edit. From the Collectors toolbar, select properties ( button on the left side of the panel. ) then select the update radio

2. Select props >> bracket. (Click props to select from the component list.) There is no bracket property in the file channel_model_org.hm . There are two properties – al and channel. You might want to rename the al property in the file. 3. Click select to complete the selection. 4. For card image = select PSHELL. 5. For material = select aluminum. (Click the text field to select from the material list.) Again, there is no aluminum material in the file channel_model_org.hm . There are two materials – st and al. You might want to rename these materials to be consistent. 6. Click update/edit to load and edit the card image and assign the material.
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Chapter 2: Interfacing with HyperMesh

7. Notice the material ID MID is 2, which is the ID of the aluminum material you created earlier and assigned to the bracket component. Again, for the channel_model_org.hm file the id of the al material is 4, not 2. You might have to renumber the materials too. 8. For the thickness [T] enter 2.0. 9. Return to the properties panel.

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Chapter 2: Interfacing with HyperMesh

Exercise 2.3: Submitting jobs from HyperMesh
This exercise demonstrates how to launch a RADIOSS job from within HyperMesh. A HyperMesh database containing a fully defined RADIOSS finite element model is retrieved and a RADIOSS job is launched from the RADIOSS panel in HyperMesh.

Exercise
Step 1: Load the User Profile
1. Launch HyperMesh. The User Profiles dialog appears upon start-up by default. 2. If the User Profiles dialog is not visible, select Preferences from the toolbar and choose User Profiles…. 3. Under Application:, select the RADIOSS radio button and from the adjacent pull-down Bulk Data. 4. Click OK. This loads the appropriate User Profile. It includes the appropriate template, macro menu, and import reader. It simplifies the menu systems to give access to only the functionality of HyperMesh that is necessary.

Step 2: Retrieve the HyperMesh database
1. From the File pull-down menu on the toolbar, select Open.... An Open file… browser window pops up. 2. Select the plate.hm file. 3. Click Open. The plate.hm database is loaded into the current HyperMesh session, replacing any existing data.

Step 3: Launch the RADIOSS job
1. Choose the Analysis page and select the RADIOSS panel. You can also choose RADIOSS from the Applications pull-down menu on the toolbar. 2. Click save as…. A Save file … browser window pops up. 3. Select the directory where you would like to write the model file and enter the file name, plate.fem, in the File name: field. The .fem file name extension is the suggested extension for RADIOSS bulk data input decks. 4. Click Save.

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Chapter 2: Interfacing with HyperMesh

Note:

The name and location of the plate.fem file now displays in the input file: field.

5. Set the export options: toggle, underneath the run options switch, to all. 6. Click the run options switch, located on the left side of the panel, and select analysis. 7. Set the memory toggle, located in the center of the panel, to memory default. 8. Click RADIOSS. This exports the input file and launches the job. If the job is successful, new results files can be seen in the directory where the model file was written. The plate.out file is a good place to look for error messages that will help to debug the input deck if any errors are present. The default files written to your directory are: plate.html HTML report of the analysis, giving a summary of the problem formulation and the analysis results. ASCII output file containing specific information on the file set up, the set up of your optimization problem, estimate for the amount of RAM and disk space required for the run, information for each optimization iteration, and compute time information. Review this file for warnings and errors. HyperMesh binary results file. Summary of analysis process, providing CPU information for each step during analysis process. HyperView binary result file.

plate.out

plate.res plate.stat

plate.h3d

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HyperWorks 9.0

Chapter 3: Linear Static Analysis

Chapter 3

Linear Static Analysis
Linear Static Analysis
This chapter gives you a basic understanding of the linear static analysis. The basic finite element equation to be solved for structures experiencing static loads can be expressed as: where K is the stiffness matrix of the structure (an assemblage of individual element stiffness matrices). The vector u is the displacement vector, and P is the vector of loads applied to the structure. The above equation is the equilibrium of external and internal forces. The stiffness matrix is singular, unless displacement boundary conditions are applied to fix the rigid body degrees of freedom of the model. The equilibrium equation is solved simultaneously for the unknown displacements using a Gauss elimination method that exploits the sparseness and symmetry of the stiffness matrix K for computational efficiency. Once the unknown displacements at the nodal points of the elements are calculated, the stresses can be calculated by using the constitutive relations for the material.

Exercises: Linear Static Analysis.............................................................................
Exercise 3.1: Bending of a channel bracket assembly ....................................................... Exercise 3.3: Thermal stress analysis of a printed circuit board.........................................

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RADIOSS Linear 39

Chapter 3: Linear Static Analysis

Linear Static Analysis
? One of the most common types of analysis ? System is subjected to loads and boundary conditions like: ? Forces, Moments, Temperature, SPC’s (Single point constraints), MPC’s (Multi point constraints)… ? Analysis has some assumptions like: ? Deformations are in the elastic range ? Stresses are assumed to be linear functions of the strains

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Linear Static Analysis
? Commonly used cards for a Linear Static analysis are:
DISPLACEMENT = ALL FORMAT H3D STRAIN = ALL STRESS = ALL $$------------------------------------------------------------------------------$ $$ Case Control Cards $ $$------------------------------------------------------------------------------$ SUBCASE 1 $Defines a subcase with an ID of 1 LABEL Test Loading SUBTITLE = Test 01 SPC = 1 $ references all single-point constraints with ID 1 LOAD = 2 $ references loads (forces, monents…) with ID 2 $ BEGIN BULK $ FORCE Data FORCE 2 11 01.0 0.0 0.0 -100.0 $ $ SPC Data SPC 1 31 1234560.0

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HyperWorks 9.0

Chapter 3: Linear Static Analysis

Linear Static Analysis
? Results of interest usually are: ? Displacements, Stresses and Strains

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RADIOSS Linear 41

Chapter 3: Linear Static Analysis

Exercise 3.1: Bending of a channel bracket assembly
In this exercise, you will learn how to: ? ? ? ? ? ? Create constraints (RADIOSS SPC) on the channel’s geometry lines Create a force (RADIOSS FORCE) on the bracket to simulate a pressing load on it Define a load step (RADIOSS SUBCASE) Export the model to a RADIOSS bulk data input file Submit the RADIOSS bulk data input file to RADIOSS Review the resulting HTML report file

The purpose for using a finite element (FE) pre-processor is to create a model, which can be run by a solver. A finite element solver can solve for responses of parts to loading conditions on them. The loads can be in the form of boundary constraints, forces, pressures, temperatures, etc. In this exercise, you will gain an understanding of the basic concepts for creating a solver input file by using a template. More specifically, learn how to define loading conditions on a model, specify solver specific controls and submit an input file to a solver from HyperMesh.

Exercise: Setting up Loading Conditions
This exercise uses the model file, channel_brkt_assem_loading.hm. It contains the bracket and channel assembly in the following image.

Step 1: Retrieve and view the HyperMesh model file channel_brkt_assem_loading.hm.
1. Go to: Start
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All Programs

Altair HyperWorks “version”

HyperMesh
HyperWorks 9.0

Chapter 3: Linear Static Analysis

When the app is launched a GUI window will show up wanting you to select a user profile. 2. Select the RADIOSS radio button on the left then select BulkData from list to the right in the User Profile dialog. 3. Open channel_brkt_assem_loading.hm in HyperMesh. The user profile can also be set or changed from the Preferences pulldown menu by selecting User Profiles…

Step 2: Create two load collectors named pressing_load and constraints.
9. Access the collectors panel by clicking load collectors ( 10. Go to the create sub-panel. 11. For loadcol name = enter pressing_load. 12. Select your desired color. 13. Switch the creation method to no card image. 14. Create the load collector pressing_load. 15. For loadcol name = enter constraints. 16. Select your desired color. 17. Create the load collector constraints. 18. Return to the main menu. ) on the collectors toolbar.

Step 3: Apply constraints (RADIOSS SPC) to the channel’s line geometry.
1. Use the model browser to display the geom ( 2. On the toolbar, click User Views ( ? ? ) for the component channel.

), and pick iso1.

3. Enter the constraints panel in one of the following ways: From the Pull-down menu, select BCs, then Create, then Constraints On the main menu, select the Analysis page, then select constraints

4. Go to the create sub-panel. 5. Switch the entity selector to lines. 6. Select the six lines on the perimeter of the channel’s bottom surface as shown in the following image.

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RADIOSS Linear 43

Chapter 3: Linear Static Analysis

7. Activate degrees of freedom (dof) 1 through 6. For a RADIOSS linear static analysis, dof 1, 2, and 3 represent translations in the global x, y, and z directions respectively. Dof 4, 5, and 6 represent rotations about the global x, y and z axis, respectively. 8. Set Load Types = to SPC. 9. Create the constraints on the lines. 10. For size = enter 5. The display size of the constraints is reduced. 11. Activate the option label constraints. A label is displayed for each constraint. The labels identify what dofs are assigned to the constraints. 12. Click return to exit to the main menu.

Step 4: Map the constraints (RADIOSS SPC) on the geometry lines to the channel nodes associated to the lines.
1. Access the load on geom panel in one of the following ways: ? ? From the Pull-down menu, select BCs, then Loads on Geometry On the main menu, select the Analysis page, then select Load on Geometry

2. Select loadcols >> constraints. 3. Click select to complete the selection of load collectors. 4. Click Map loads.

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A constraint is at each node associated to the geometry lines. 5. Click return to exit to the main menu. 6. On the model browser, turn off the display of geometry for all component collectors.

Sttep 5: Prepare to create forces (RADIOSS FORCE) on the bracket for the pressing load case.
1. On the toolbar, click User Views ( ) and pick restore1.

2. On the model browser, right click on the pressing_load load collector and select Make Current. The pressing_load load collector is now the current load collector, and any loads created will be placed in this collector.

Step 6: Create two forces (RADIOSS FORCE) on the bracket for the pressing load case.
1. Access the forces panel in one of the following ways: ? ? From the Pull-down menu, select BCs, then Forces On the main menu, select the Analysis page, then select Forces

2. Go to the create sub-panel. 3. With the nodes selector active, select the two nodes as indicated in the following image.

4. For magnitude = enter 5. 5. Switch the direction selector from N1, N2, N3 to y-axis. 6. Set Load Types = to Force. 7. Create the forces.

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8. For magnitude % = specify 200.0. The display size of the force is increased. 9. Activate the option label loads. Each force displays the label FORCE = 5.00e+00.

The two forces created for the pressing load case

10. Click return to exit to the main menu.

Step 7: Define the load step for the pressing load case.
1. Access the load step panel in one of the following ways: ? ? From the Pull-down menu, select Setup, then Create, then Load Steps On the main menu, select the Analysis page, then select load steps

2. For name = enter pressing_step. 3. Switch name to name(id). This shows the names of the load collectors with their ID numbers in parenthesis. 4. Set the type: to linear static. 5. Activate the SPC and LOAD options. 6. Click the = next to SPC. 7. Select the constraints load collector. Note that the field next to the = now has a value of 2, which is the ID of the constraints load collector. 8. Click the = next to LOAD and select the pressing_load load collector. 9. Create the load step pressing_step. In the status bar appears the message "The load step has been created". Nothing new is displayed in the graphics area.

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10. Click return to exit to the main menu.

Step 8: Display the load step on and off (the load collectors defined in the load step).
1. On the model browser, turn the display of the load step pressing_step off. 2. Notice the load collector’s constraints and pressing_load are no longer displayed. 3. Turn the display of the load step pressing_step back on.

Step 9: Define a H3D file to be output from RADIOSS by using the control cards panel.
1. Access the control cards panel in one of the following ways: ? ? From the Pull-down menu, select Setup, then Create, then Control Cards On the main menu, select the Analysis page, then select control cards

2. Select the control card FORMAT. You may need to click next to get to the second page of cards. Notice in the card image the one FORMAT line is set to H3D. This specifies RADIOSS to output results to a Hyper3D (H3D) file, which can be viewed in HyperView Player. Also, an HTML report file will be output and the H3D file will be embedded in it. 3. For number_of_formats = specify 2. A second FORMAT line appears in the card image. 4. Click H3D in the second line of the card image and select HM. This specifies RADIOSS to output the results to a HyperMesh binary results file, allowing the results to be post-processed within HyperMesh. 5. Click return to exit to the control cards panel. Notice the FORMAT button is green. This indicates the card will be exported to the RADIOSS input file. 6. Click return to exit to the main menu.

Step 10: Export the model to an RADIOSS Bulk Data input file.
1. On the File menu, click Export. 2. In the Export tab, for Export Type: specify FE Model. 3. In the File name: field, type channel_brkt_assem_loading.fem. Note that the extension for an RADIOSS Bulk Data input file is .fem. 4. Click Save to export the model as an RADIOSS .fem input file. 5. Click Apply. This exports the model as an input file for the solver specified by the current user profile.

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Step 11: Review the contents of the file channel_brkt_assem_loading.fem.
1. Using any text editor (Notepad, Wordpad, Vi, etc.), open the file channel_brkt_assem_loading.fem. 2. Near the top of the file, notice as shown in the following image: ? ? ? The line FORMAT HM which you specified in HyperMesh The load step (RADIOSS Bulk Data SUBCASE) named pressing_step which you defined in HyperMesh Under the load step, the load collector ids (RADIOSS load and constraint set identification numbers)

3. Search for "FORCE". Notice the load set identification number for each force (RADIOSS FORCE). It is either 1 or 2 as shown in the following image. These numbers correspond to the numbers under the load steps in the file.

4. Search for "SPC" (HyperMesh constraint). Notice the constraint set identification number for each constraint (RADIOSS SPC). It is 3 as shown in the following image, which lists a few of the constraints. This number corresponds to the number under the load steps in the file.

5. Search for the load collector name "pressing_load". Notice the load collectors pressing_load and constraints. Also, notice their collector ID and color ID. When the model is imported into HyperMesh, the loads are organized into these load collectors and have these IDs and colors.

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6. Close the file channel_brkt_assem_loading.fem.

Step 12: Save your work.
With the exercise completed, you can save the model as a HyperMesh file.

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Exercise 3.2: Thermal stress analysis of a printed circuit board with anisotropic material properties
Purpose
Printed Circuit Boards (PCB’s) are used in electronic components to both mechanically support and provide electrical connections between components. Construction involves etching a thin copper layer that has been deposited onto a non-conductive, glassfiber/epoxy composite substrate. Electrical components are then mounted to the board and connected to the copper traces with electrical solder. The concentrated, intense heating that occurs during the soldering process creates stresses in the substrate material. In this exercise, we will simulate this process and determine if the stresses and strains resulting from this process are acceptable or not. The model will make use of solid hexahedral (CHEXA8) elements with a thin skin of shell elements (CQUAD4) on the outside faces. The consistent unit system used in this simulation will be: kg, mm, GPa, kN and ° C.

Problem Statement
In this exercise, you will learn how to: ? ? ? ? ? Create MAT2 and MAT9 material definition cards Create PSOLID and PSHELL element property cards Create applied temperature loads and constraints (TEMP and SPC cards) Create a temperature loading subcase Request strain output with the STRAIN control card

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Exercise 3.2:
Step 1: Retrieve the model circuit_board.hm Step 2: Create a MAT9 material definition for the solid elements
The MAT9 material type defines the properties for linear, temperature independent, anisotropic materials. This material model is well suited to this problem, due to the composite structure of the substrate. The X, Y and Z orientations of the laminated material have different elastic moduli and thermal expansion coefficients. The MAT9 material applied to solid elements allows a simplification of the model over using a shell model of the composite, with the individual ply layer properties and orientations defined. 1. Access the Materials: panel: ? ? From the toolbar, by clicking on the materials icon, or

Through the Model Tab on the Model browser menu right click and select create material.

2. In the create sub panel Next to mat name= field, enter PCB_solids. 3. Set the card image to MAT9. 4. Click create/edit to create the material and enter the card image editor. Enter the following values for the oriented elastic and shear modulus of the composite: Note: G11 17.0 If a required field is not active, click the field heading to activate it. G22 16.2 G33 7.00 G44 4.93 G55 4.70 G66 2.03

Enter the following values for the thermal expansion rates and reference temperature: A1 1.6e-5 A2 1.9e-5 A3 8.0e-5 TREF 10.0

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5. Once the values have been entered, click return to close the card editor and return to the Materials: panel.

Step 3: Create a MAT2 material definition for the shell elements
You should still be in the materials/create panel from the previous step. 1. In the name= field, enter PCB_shells. 2. Set the card image to MAT2. 3. Click create/edit to create the material and enter the card image editor. Enter the following values for the shell element material properties: G11 17.0 G22 16.2 G33 4.90 A1 1.6e-5 A2 1.9e-5 TREF 10.0

4. Once the values have been entered, click return to close the card editor and return to the Materials: panel.

Step 4: Create Properties with a material reference and Update the existing components
1. Click Model tab on the Tab menu 2. Right click inside the Model Browser window and activate the menu over Create and click Property 3. In the Name: field type shell. 4. Select PSHELL as Property type by clicking on Card image. 5. Select pcb_shells as the Material:. 6. Click on Create/Edit. 7. The PSHELL card image pops up. 8. Enter the thickness for the shell component by clicking T, clicking in the text box, and typing 0.001.
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9. Repeat steps 1 thru 8 and create another property with name as Solids with card image as “PSOLID” and Material as “pcb_solids”. 10. From Collectors pull down menu, activate menu over Edit and click Components. 11. Click on comps, check the box pcb_solids and click select 12. Toggle <no property> to property = 13. Double click on property = and select solids 14. Click on update 15. Click on comps and select both solder_pads and shell_faces click select 16. Toggle <no property> to property = 17. Double click on property = and select shells 18. Click on update 19. Click Return.

Step 5: Create displacement constraints at the mounting holes
1. Right click inside the Model Browser window and activate the menu over Create and click LoadCollector 2. In the Name: field type constraints. 3. Leave the Card Image: field to None 4. Select a suitable color. 5. Click on Create 6. From the Analysis page, go to the constraints panel. 7. With the panel in the create sub-panel, click the yellow nodes selector. 8. From the extended selection menu, select the by sets option. 9. Select the constrain_nodes entity set. 10. Leave all 6 degrees of freedom selected, then click create. 11. Click return to go back to the main menu.

Step 6: Create applied temperature loads at the solder pad locations
1. Create a new load collector named temperature loads. No card image is required. 2. From the Analysis page, go to the temperatures panel. 3. With the panel in the create mode: ? ? ? Click the yellow nodes selector. Select by collector then; Check the box next to the solder_pads component. 4. From the extended selection menu:

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?

Click select

5. Set the load definition to constant value (the field label specifies value=) and enter 345.0. 6. Click create to create the temperature loads. 7. Click return to go back to the main menu.

Step 7: Create a thermal stress analysis subcase
1. From the Analysis page, go to the Loadsteps panel. 2. Set the analysis type to linear static. 3. For the subcase name, enter thermal_loading. 4. Activate the SPC and TEMP load fields. 5. Click in the integer field for the SPC load and select the constraints load collector. 6. In the temp field, select the temperature_loads load collector. 7. Click create to create the analysis subcase. 8. Click return to go back to the main menu.

Step 8: Add FORMAT, STRAIN and SCREEN control cards to the analysis deck
1. From the Analysis page, go to the control cards panel. 2. Click FORMAT to add card requesting output results format. 3. For the number_of_formats field on the lower part of the panel, enter 2. 4. Set one of the format lines to OUTPUT2 to request the OP2 format results file. 5. Then click return to go back to the control cards panel. 6. Click the next button to advance to the second page of control cards, then once more to go to the third page. 7. Activate the SCREEN card with the OUT option. 8. Then return to the control card panel. 9. Activate the STRAIN card to request strain results output. Leave the default settings for this card. 10. Return to the main menu.

Step 9: Launch the RADIOSS analysis
Create a new folder for this run; then submit the job for analysis. From the Analysis page, use the RADIOSS panel.

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Chapter 4

Normal Modes Analysis
Normal Modes Analysis
This chapter gives you a basic understanding of Normal Modes analysis. The equilibrium equation for a structure performing free vibration appears as the eigenvalue problem:

Where K is the stiffness matrix of the structure and M is the mass matrix. Damping is neglected. The solution of the eigenvalue problem yields n eigenvalues , where n is the number of degrees of freedom. The vector x is the eigenvector corresponding to the eigenvalue. The eigenvalue problem is solved using a matrix method called the Lanczos method. Not all eigenvalues are required -- only a small number of the lowest eigenvalues are normally calculated. The natural frequency follows directly from the eigenvalue .

Exercises: Normal Modes Analysis..........................................................................
Exercise 4.1: Channel bracket assembly ........................................................................... Exercise 4.2: Post-processing in HyperView..................................................................... Exercise 4.3: Normal Modes Analysis of a Splash Shield .................................................. Exercise 4.4: Review the results using HyperView ............................................................

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Normal Modes Analysis
? Normal Modes analysis is performed when you are interested in the natural frequencies and the mode shapes of the structure.

Tacoma Narrows Bridge in Washington

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Normal Modes Analysis
? Results of interest usually are :
? Mode shapes, resonant frequencies

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Normal Modes Analysis
? The required card for Normal Modes analysis is EIGRL:
FORMAT H3D $$------------------------------------------------------------------------------$ $$ Case Control Cards $ $$------------------------------------------------------------------------------$ SUBCASE 2 LABEL Normal Modes Run SUBTITLE = Nominal SPC = 1 $ references all single-point constraints with ID 1 METHOD = 3 $ references the EIGRL card with ID 3 $ BEGIN BULK $ EIGRL 3 20 MASS $ $ SPC Data SPC 1 31 1234560.0

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Bulk Data section Normal Modes
? Example local coordinate system (EIGRL card):
(1) EIGRL (2) SID V1 (3) V2 (4) ND (5) (6) MSGLVL (7) MAXSET (8) SHFSCL (9) NORM (10)

Where:
SID V1,V2 ND MSGLVL MAXSET SHFSCL Unique set identification number. (Integer > 0) For vibration analysis: Frequency range of interest For buckling analysis: Eigenvalue range of interest. Number of roots desired. (Integer > 0 or blank) Number of roots desired. (Integer > 0 or blank) Number of vectors in block or set. Default = 8 (Integer 1 through 16 or blank) For vibration analysis: Estimate of the frequency of the first flexible mode. For buckling analysis: Estimate of the first eigenvalue. MASS buckling). NORM eigenvectors are normalized to generalized mass (not valid for

MAX eigenvectors are normalized to the unit value of the largest displacement. Default = MASS for normal modes analysis, MAX for linear buckling analysis

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Exercise 4.1: Normal Modes of a channel bracket assembly
Purpose
Again, the purpose for using a finite element (FE) pre-processor is to create a model, which can be run by a solver. A finite element solver can solve for responses of parts to loading conditions on them. The loads can be in the form of boundary constraints, forces, pressures, temperatures, etc. In this exercise, continue to gain an understanding of the basic concepts for creating a solver input file by using a template. More specifically, learn how to define loading conditions on a model, specify solver specific controls and submit an input file to a solver from HyperMesh.

Problem Statement
This exercise uses the file channel_brkt_assem_loading.fem from Exercise 3.1. It contains the boundary conditions and loadcases you generated from this exercise. Complete the setup of the model for a RADIOSS analysis for the normal modes. To do this you will need to define the EIGRL loadcollector and the normal modes loadstep.

This exercise involves doing the following:

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Exercise 4.1:
Step 1: Retrieve and view the RADIOSS fem model file from exercise 3.1 channel_brkt_assem_loading.fem. Step 2: Update the material properties to specify Density (RHO).
A material density is required for the normal modes solution sequences 1. From the toolbar, enter thematerial collectors 3. Click on yellow mats button. 4. Select steel and click on update/edit. 5. Click on RHO. The default value for steel is pre-defined. 6. Click return. 7. Click on the yellow mats button again and select aluminum. 8. Click on RHO and specify 2.7e-9. 9. Click return twice to go the main menu. panel.

2. Go to the update subpanel using the radio buttons on the left side of the panel.

Step 3: Create a load collector named EIGRL.
To perform a normal modes of analysis, a real eigenvalue extraction (EIGRL) card needs to be referenced in the subcase. 1. From the toolbar, enter the load collectors 3. For name = enter EIGRL. 4. Click on the toggle next to no card image and select card image. 5. Click on card image= and choose EIGRL from the extended selection menu.. 6. Click Create/edit. 7. Click ND. This allows you to set the number of modes you wish to request. 8. Enter 10 in the field. 9. Click Return twice to go to the main menu. panel. 2. Go to the create subpanel using the radio buttons on the left side of the panel.

Step 4: Create a loadstep named normal_modes.
1. From the main menu enter the loadsteps panel. 2. Enter the name normal_modes.

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3. Set the type to normal modes. 4. Check the box next to SPC and select constraints from the prior setup. 5. Check the box next to METHOD (STRUCT) and select the EIGRL load collector created earlier. 6. Click Create.

Step 5: Submit the FEM file to RADIOSS using the solver panel.
1. From the Applications pull-down menu select the RADIOSS to go to the RADIOSS panel. 2. For input file:, click on save as… 3. Enter the filename as channel_brkt_assem_modal.fem.and click on Save 4. Click RADIOSS to invoke RADIOSS and run the analysis. A command window appears. When the analysis is complete, the message “Processing complete” appears in the command window. The output files are located in the same folder containing the input file.

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Exercise 4.2: Postprocessing in HyperView
Review the normal modes
1. From the same panel click HyperView. 2. Click Ok to close the Warning! Dialog. 3. Click Close to close the Message Log window.

4. Toggle the Stoplight Icon 5. Go to the Deformed panel

to choose Modal from the toolbar.

6. Click on the Load Case and Simulation Selection dialog and choose Subcase 2 – normal modes. 7. Click OK to close the Load Case and Simulation Selection dialog. 8. Under Result Type: choose Eigen Mode (v) 9. Under Scale: choose Model Units 10. Leave Type: to Uniform 11. Enter a value of 10.0 for Value: This means that the maximum displacement will be 10 modal units for all other displacements will be proportional 12. Click Apply 13. Click on the Modal Icon to animate.

14. To control the animation speed use the Animation Controls accessed with the director’s chair toolbar button .

15. Click the Modal Icon again to stop the animation. You can also animate the other 9 modes. And the linear static results using the subcase selector in the bottom right corner. 16. Once you are finished viewing, select File from the pull-down menu and choose Exit to exit HyperView

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Exercise 4.3 Normal Modes Analysis of a Splash Shield
In this exercise, an existing finite element model of an automotive splash shield will be used to demonstrate how to set up and perform a normal modes analysis. HyperMesh postprocessing tools are used to determine mode shapes of the model. The following steps are included: ? ? ? ? Retrieving the RADIOSS input file Setting up the model in HyperMesh Submitting the job Viewing the results

Applying Loads and Boundary Conditions to the Model

The following file is needed to perform this tutorial:

Exercise 4.3:
Step 1: Launch HM and set the RADIOSS OptiStruct User Profile
1. Launch HyperMesh. (A User Profiles… GUI will appear.) 2. Choose RADIOSS, (Bulk Data Format) in the User Profile dialog and click OK. This loads the user profile. It includes the appropriate template, macro menu, and import reader, paring down the functionality of HyperMesh to what is relevant for generating models in Bulk Data Format for RADIOSS and OptiStruct. User Profiles… can also be accessed from the Preferences pull-down menu on the toolbar.

Step 2: Import a Finite Element Model file in HyperMesh
1. From the File pull-down menu on the toolbar, select Import…. An Import… tab is added to your tab menu. 2. Select the Import type: FE Model. 3. Choose the proper File type: RADIOSS (Bulk Data). 4. Select the Files: icon. 5. A Select RADIOSS(Bulk Data) file browser will pop up. 6. Browse for sshield.fem file. 7. Click Open 8. Click Apply 9. Click Close to close the Import tab menu

Setting up the problem in HyperMesh (Steps 3 - 4)
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Step 3: Review rigid elements
Notice there are two rigid "spiders" in the model. They are placed at locations where the shield is bolted down. This is a simplified representation of the interaction between the bolts and the shield. It is assumed that the bolts are significantly more rigid in comparison to the shield. The dependent nodes of the rigid elements have all six degrees of freedom constrained. Therefore, each "spider" connects nodes of the shell mesh together in such a way that they do not move with respect to one another. The following steps show how to review the properties of the rigid elements. 1. From the 1D page, select the rigids. 2. Click review. 3. Select one of the rigid elements in the graphics region. In the graphics window, HyperMesh displays the IDs of the rigid element and the two end nodes and indicates the independent node with an ' and the dependent node with a I' ' . HyperMesh also indicates the constrained degrees of freedom for the selected D' element, through the dof checkboxes in the rigids panel. All rigid elements in this model should have all dofs constrained. 4. Click return to go to the main menu.

Step 4: Setting up the material and geometric properties
The imported model has three component collectors with no materials. A material collector needs to be created and assigned to the shell component collectors. The rigid elements do not need to be assigned a material. Shell thickness values also need to be corrected. 1. Select the Material Collectors toolbar button 3. Click mat name = and enter steel. 4. Click card image = and select MAT1 from the pop-up menu. 5. Click create/edit. 6. The MAT1 card image pops up. 7. For E, enter the value 2.0E5. 8. For NU, enter the value 0.3. 9. For RHO, enter the value 7.85E-9. If a quantity in brackets does not have a value below it, it is off. To change this, click the quantity in brackets and an entry field will appear below it. Click in the entry field, and a value can be entered. 10. Click return. A new material, steel, has now been created. The material uses RADIOSS' linear s isotropic material model, MAT1. This material has a Young' Modulus of 2E+05, a s .

2. Select the create subpanel using the radio buttons on the left-hand side of the panel.

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Poisson' Ratio of 0.3 and a material density of 7.85E-09. A material density is required s for the normal modes solution sequence. 11. At any time, the card image for this collector can be modified using Card Editor. 12. Click return to exit the Materials: Create panel. 13. Select the Card Editor toolbar button .

14. Click the down arrow on the right of the entity shown in the yellow box, choose props from the extended entity list. 15. Click the yellow props button and then check the box next to design and nondesign 16. Click select. 17. Make sure card image= is set to PSHELL. 18. Click edit. 19. The PSHELL card image for the design component collector pops up. 20. Replace 0.300 in the T field with 0.25. 21. Click return to save the changes to the card image. 22. Click return to go to the main menu.

Applying Loads and Boundary Conditions to the Model (Steps 5 - 7)
The model is to be constrained using SPCs at the bolt locations, as shown in the following figure. The constraints will be organized into the load collector, ' constraints' . To perform a normal modes analysis, a real eigenvalue extraction (EIGRL) card needs to be referenced in the subcase. The real eigenvalue extraction card is defined in HyperMesh as a load collector with an EIGRL card image. This load collector should not contain any other loads.

Step 5: Create EIGRL card (To request the number of modes)
1. Click the Load collectors toolbar button 3. Click loadcol name = and enter EIGRL. 4. Click card image= and choose EIGRL from the pop-up menu. 5. Click create/edit. 6. For V2, enter the value 200.000. 7. For ND, enter the value 6. If a quantity in brackets does not have a value below it, it is off. To change this, click on the quantity in brackets and an entry field will appear below it. Click on the entry field, and a value can be entered. 8. Click return to save changes to the card image. .

2. Select the create subpanel, using the radio buttons on the left side of the panel.

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Step 6: Create constraints at bolt locations
1. Click loadcol name = and enter constraints 2. Click the switch next to card image and choose no card image 3. Click on color and pick a color of choice. 4. Click create 5. Click return. 6. From Analysis page, click the constraints panel and make sure that the create subpanel is active.

Selecting nodes for constraining the bolt locations (zoomed in from a top view).

7. Select the two nodes, shown in the figure above, at the center of the rigid spiders, by clicking on them in the graphics window. 8. Constrain all dofs. 9. Click on Load Type= and choose SPC. 10. Click create Two constraints are created. Constraint symbols (triangles) appear in the graphics window at the selected nodes. The number 123456 is written beside the constraint symbol, indicating that all dofs are constrained. 11. Click return to go the main menu.

Step 7: Create a Load Step to perform Normal Modes Analysis
1. From the Analysis page, select the loadsteps panel. 2. Click name = and enter bolted. 3. Click the type: switch and choose normal modes from the pop-up menu. 4. Check the box preceding SPC.
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An entry field appears to the right of SPC. 5. Click on the entry field and select constraints from the list of load collectors. 6. Check the box preceding METHOD(STRUCT). An entry field appears to the right of METHOD. 7. Click on the entry field and select EIGRL from the list of load collectors. 8. Click create. An RADIOSS subcase has been created which references the constraints in the load collector constraints and the real eigenvalue extraction data in the load collector EIGRL. 9. Click return to go to the main menu.

Submit the job
Step 8: Save the database
1. Click on the File pull-down menu from the toolbar. 2. Click save as… to set the directory in which to save the file and, in File name:, type sshield_complete.hm 3. Click Save.

Step 9: Running Normal Modes Analysis
1. From the Analysis page, select the RADIOSS panel 2. Click save as… following the input file: field A Save file… browser window pops up. 3. Select the directory where you would like to write the file and enter the name sshield_complete.fem in the File name: field. 4. Click Save 5. Note that the name and location of the sshield_complete.fem file shows in the input file: field. 6. Set the export options: toggle to all. 7. Click the run options: switch and select analysis. 8. Set the memory options: toggle to memory default. 9. Click RADIOSS. This launches the RADIOSS job. If the job was successful, new results files can be seen in the directory where the RADIOSS model file was written. The sshield_complete.out file is a good place to look for error messages that will help to debug the input deck if any errors are present.

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The default files written to your directory are:

sshield_complete.html

HTML report of the analysis, giving a summary of the problem formulation and the analysis results. RADIOSS output file containing specific information on the file set up, the set up of your optimization problem, estimates for the amount of RAM and disk space required for the run, information for each optimization iteration, and compute time information. Review this file for warnings and errors. Hyper 3D binary results file. Summary of analysis process, providing CPU information for each step during analysis process.

sshield_complete.out

sshield_complete.h3d sshield_complete.stat

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Exercise 4.4 Review the results using HyperView
Eigenvector results are output, by default, from RADIOSS for a normal modes analysis. This section describes how to view the results in HyperView.

Step 1: Load the model and result files into the animation window
In this section, you will load a HyperMesh .h3d file into the HyperView animation window. 1. Click the HyperView button in the RADIOSS panel. HyperView is launched and the sshield_complete.h3d file is loaded. 2. Click Close to exit the Message Log menu that appears.

Step 2: View Eigen Vectors
It is helpful to view the deformed shape of a model to determine if the boundary conditions have been defined correctly and also to check if the model is deforming as expected. In this section, use the Deformed panel to review the deformed shape for last Mode. 1. Click on the switch next to the traffic light signal 2. Select the Deformed toolbar button 4. Set Scale: to Model Units. 5. Set Type: to Uniform: and type in a scale factor of 10 for Value. This means that the maximum displacement will be 10 modal units and all other displacements will be proportional. Using a scale factor higher than 1.0 amplifies the deformations while a scale factor smaller than 1.0 would reduce them. In this case, we are accentuating displacements in all directions. . and choose Modal .

3. Leave Result type set to Eigen Mode(v).

6. Click Apply. 7. Set Show: under Undeformed shape: to Wireframe. (The point 2 has to come after the point 3) A deformed plot of the model overlaid on the original undeformed mesh is displayed in the graphics window.

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8. From the Graphics pull-down menu, choose Select Load Case to activate the Load Case and Simulation Selection dialog as shown below.

9. Select Mode 6 - F=1.496557E+02 from the list and click OK to view Mode 6. 10. To animate the mode shape, click the animation mode: modal .

11. To control the animation speed, use the Animation Controls accessed with the director’s chair toolbar button .

12. You could also review the rest of the mode shapes. 13. Once you are finished viewing, select File from the pull-down menu and choose Exit to exit HyperView

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Chapter 5: Inertia Relief Analysis

Chapter 5

Inertia Relief Analysis
Inertia Relief Analysis
This chapter gives you a basic understanding of inertia relief analysis. Inertia relief allows the simulation of unconstrained structures. Typical applications are an airplane in flight, suspension parts of a car, or a satellite in space. With inertia relief, the applied loads are balanced by a set of translational and rotational accelerations. These accelerations provide body forces, distributed over the structure in such a way that the sum total of the applied forces on the structure is zero. This provides the steady-state stress and deformed shape in the structure as if it were freely accelerating due to the applied loads. Boundary conditions are applied only to restrain rigid body motion. Because the external loads are balanced by the accelerations, the reaction forces corresponding to these boundary conditions are zero.

Exercises: Linear Static Analysis.............................................................................
Exercise 5.1: Control Arm.................................................................................................. Exercise 5.2: Post-processing in HyperView.....................................................................

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Inertia Relief
? Inertia Relief analysis allows the simulation of unconstrained structures ? Typical applications are: ? An airplane in flight ? Suspension parts of a car ? Satellite in space ? This provides the steady-state stress and deformed shape in the structure as if it were freely accelerating due to the applied loads

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Inertia Relief
? A few different ways of requesting for an Inertia Relief analysis
SUBCASE 6 $ Defines subcase number 6 LOAD = 6 $ references all static load cards with ID = 6 SUPORT1 = 8 $ references all SUPORT1 cards with ID = 8

SUBCASE 6 $ Defines subcase number 6 LOAD = 6 $ references all static load cards with SID = 6 … BEGIN BULK SUPORT, 10,6, $Grid ID, DOF’s Supported, …

SUBCASE 6 $ Defines subcase number 6 LOAD = 6 $ references all static load cards with ID = 6 … BEGIN BULK PARAM,INREL,-2 $Defines inertia relief without a suport point

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Inertia Relief
? Results of interest usually are :
? Displacements, Stresses and Strains

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Chapter 5: Inertia Relief Analysis

Exercise 5.1: 3-D Inertia Relief Analysis
An existing finite element model will be in this tutorial to demonstrate how HyperMesh may be used to set-up an inertia relief analysis. The analysis is then performed using RADIOSS and post-processed in HyperView. The figure illustrates the structural model used for this exercise.

Structural model with static loads and support constraints applied.

The following exercises are included: ? ? ? Setting up the problem in HyperMesh using SUPORT/SUPORT1 Submitting the job Viewing the results

Please note that beginning with 8.0, there is a parameter PARAM, INREL, -2 that can activate inertia relief analysis without the need for a SUPORT/SUPORT1 entry. You can activate that parameter by clicking on the PARAM field on the control cards panel. In this chapter, it was our intention to show the steps in creating SUPORT1 cards; hence the parameter was not used.

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Exercise 5.1:
Step 1: Launch HM, set the RADIOSS user profile and retrieve the HM model ie_carm.hm
1. Launch HyperMesh. 2. Choose RADIOSS, (Bulk Data Format) in the User Profile dialog and click OK. This loads the user profile. It includes the appropriate template, macro menu, and import reader, paring down the functionality of HyperMesh to what is relevant for generating models in Bulk Data Format for RADIOSS and OptiStruct. User Profiles… can also be accessed from the Preferences pull-down menu on the toolbar. 3. Select the File icon from the Standard toobar.

An Open file… browser window pops up. 4. Select the ie_carm.hm file and Click Open. 5. Click Open. The ie_carm.hm database is loaded into the current HyperMesh session, replacing any existing data. The database only contains geometric data. Note the location of ie_carm.hm now displays in the file: field.

Step 2 Create load collectors used to conduct the inertia relief analysis
In this section you will create two collectors one for static loads and the other for constraints. 1. Click the Load Collector Panel toolbar button 3. Click loadcol name = and enter static_loads. 4. Click color and pick a color from the palette. 5. Click the creation method switch and select no card image from the pop-up menu. 6. Click create. A new load collector, static_loads, is created. 7. Click loadcol name = and enter SPCs. 8. Click color and pick another color. 9. Click create. A new load collector, SPCs, is created. 10. Click return to go to the main menu. .

2. Select the create subpanel using the radio buttons on the left-hand side of the panel.

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Step 3: Create the SUPORT1 required in the analysis
1. Click Set Current Load Collector panel located at the right bottom corner of HM GUI. A list of load collectors pop up. 2. Select SPCs as the current load collector. You will see SPCs appears in the field as shown below.

Set current load collector

3. From the Analysis page, select constraints to enter the panel. 4. Go to create sub panel. 5. Verify the yellow entity selector is set to nodes. If not, click the switch to the left and choose nodes. 6. Select the node that sits in the middle of the multi-node rigid on the foremost attachment point of the control arm to the chassis. This can be seen in the following figure as 1st constraint. 7. Deselect the degrees of freedom dof4 through dof6 by clicking to uncheck the box beside each. 8. Click load type = and select SUPORT1 from the pop-up menu. The load type is modified to perform inertia relief analysis. 9. Click the create button. 10. Choose the node and the reward attachment point of the control arm of the chassis that can be seen in the figure as 2nd constraint applied. 11. Remove the dof1 and verify the nodes button remains active. 12. Click create.

Nodes to be selected for constraint boundary conditions.

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13. Create the third constraint by deselecting the dof 2 and choosing the top node in the rigid which would fasten the bottom of the shock assembly to the control arm. This can be seen in the next figure. 14. Click create.

Final constraint applied to control arm model.

15. Click return to go back to Analysis page.

Step 4: Create the static forces for the analysis
1. Select static_load as the current load collector by clicking the Set Current Load Collector panel. 2. From the Analysis page, select forces. 3. Verify the yellow entity selector is set to nodes. If not, click the switch and choose nodes. 4. Select the node on the top of the rigid at the end of the control arm. 5. Set magnitude = to -1e+05. 6. Click the switch beside N1N2N3 and choose x-axis. 7. Click create. 8. Choose the same node. 9. Set magnitude = to 3e+05. 10. Change the force orientation to the z-axis. 11. Click create. The forces can be seen in the next figure. 12. Click return and go back to Analysis panel.

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Application of static forces.

Step 5: Create the RADIOSS subcase
1. From the Analysis page, select loadsteps to enter the panel. 2. Click name = and enter linear. 3. Toggle the type: selection switch and select linear static. . 4. Check the box preceding LOAD. An entry field appears to the right of LOAD. 5. Click on the entry field and select static_loads from the list of load collectors. 6. Check the box preceding SUPORT1. An entry field appears to the right of SUPORT1. 7. Click on the entry field and select SPCs from the list of load collectors. 8. Click create. A RADIOSS loadstep has been created which references the inertia relief support points in the load collector SPCs and the forces in the load collector static_loads. 9. Click return to go to the main menu.

Step 6: Create the control cards necessary to conduct the inertia relief analysis
1. From the Analysis page, select control cards to enter the panel. 2. Click TITLE and enter a title for this inertia relief analysis. 3. Click PARAM and scroll down to turn on INREL.
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4. Under INREL_V1, toggle the selection to be -1. This requests that inertia relief analysis be performed. 5. Click return twice to go to the main menu.

Submitting the Job Step 7: Run the inertia relief analysis
The RADIOSS panel accomplishes two things: it saves the current model with its settings to create the input file RADIOSS will use, and allows you to select the type of analysis. 1. From the Analysis page, select the RADIOSS panel. 2. Ensure ie_carm.fem is in the field after input file:. If not, click save as….and type ie_carm.fem.. The file extension, .fem, is necessary for RADIOSS to recognize it as an input file. 3. Set the run options: switch to analysis. 4. Leave the toggle for memory options: set to memory default. 5. Click RADIOSS. This launches the RADIOSS job. If the job is successful, you should see new results files in the directory where HyperMesh was invoked. The ie_carm.out file is a good place to look for error messages that will help you debug your input deck if any errors are present. The default files that will be written to your directory are: ie_carm.html Web-based file which gives a summary of the input deck and simulation conducted. ie_carm.h3d Results file which contains everything from displacement to stress results that can be viewed in HyperView. HyperMesh binary results file. ASCII based output file of the model check run before the simulation begins and gives some basic information on the results of the run.

ie_carm.res ie_carm.out

ie_carm.stat Detailed breakdown on the CPU time used for each significant stage in the analysis.

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Chapter 5: Inertia Relief Analysis

Exercise 5.2: Post-processing in HyperView
Viewing the Results
RADIOSS provides contour information for all of the loadsteps that were run. This section describes the process for viewing those results in HyperView.

Step 1: View a deformed shape
1. From the RADIOSS panel, click the HyperView button. This automatically launches HyperView and reads in the .h3d file created in the previous step. 2. Verify that the Animate Mode Menu is set to Linear Static as shown below.

3. Click the Deformed panel toolbar button 4. Set Result Type: to Displacement(v).

.

5. Set Scale to Model units and enter a value of 10. This means that the maximum displacement will be 10 model units and all other displacements will be proportional. 6. Click Apply. 7. Set the toggle under Undeformed Shape to Wireframe and select Color as the Component. A deformed plot of the model should be visible, overlaid on the original undeformed mesh.

Step 2: View a deformed animation of the loading displacement
1. Verify that the Animate Mode Menu is set to Linear Static. 2. Click the cantilever beam icon 3. Click the director’s chair icon to start the animation. to go to the Animation Controls panel.

4. With the animation running, use the slider bar next to Speed: on the left side of the panel to adjust the speed of the animation. 5. Click the cantilever beam icon again to stop the animation.

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Step 3: View a von Mises stress contour of the static loadcase
1. Click the contour panel on the toolbar button 3D) as the Result type:. 2. The stress type should be set to vonMises. 3. Click Apply and notice the graphical display of stresses. 4. Once you are finished viewing, select File from the pull-down menu and choose Exit to exit HyperView. and select Element Stresses (2D &

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Chapter 6: Buckling Analysis

Chapter 6

Buckling Analysis
Buckling Analysis
This chapter gives you a basic understanding of buckling analysis. The problem of linear buckling in finite element analysis is solved by first applying a reference level of loading, , to the structure. A standard linear static analysis is then carried out to obtain stresses which are needed to form the geometric stiffness matrix . The buckling loads are then calculated by solving an eigenvalue problem:

is the stiffness matrix of the structure and is the multiplier to the reference load. The solution of the eigenvalue problem generally yields n eigenvalues , where n is the number of degrees of freedom (in practice, only a subset of eigenvalues is usually calculated). The vector x is the eigenvector corresponding to the eigenvalue. The eigenvalue problem is solved using a matrix method called the Lanczos method. Not all eigenvalues are required. Only a small number of the lowest eigenvalues are normally calculated for buckling analysis. The lowest eigenvalue is associated with buckling. The critical or buckling load is:

Exercises: Buckling Analysis ...................................................................................
Exercise 6.1: 3-D Buckling Analysis .................................................................................. Exercise 6.2: Post-processing in HyperView.....................................................................

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Chapter 6: Buckling Analysis

Linear Buckling Analysis
? Structures are said to "buckle" when a certain combination of loads causes the structure to continue to deflect without an increase in the magnitude of the load The critical load at which buckling occurs is the product of the critical buckling factor and the applied reference load The buckling factor is an eigenvalue and has no dimension Generally speaking, the lowest buckling load is usually of the most interest to engineers, since a structure will fail prior to reaching any higher buckling loads

?

? ?

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Linear Buckling Analysis
? The problem of linear buckling is solved in two stages: ? ? ? A standard linear static analysis is carried out to obtain stresses, which form the geometric stiffness matrix . The buckling loads are then calculated by solving the eigenvalue problem.
$$------------Case Control Cards ------------ $ $ SUBCASE 1 SPC = 2 LOAD = 3 $ SUBCASE 2 SPC = 2 METHOD = 1 STATSUB = 1 $ BEGIN BULK EIGRL 1 2 FORCE 3 82 01.0 0.0 0.0 SPC 2 1 123 0.0

Requires STATSUB card for a Buckling Analysis:

MASS -1000.0

$
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Chapter 6: Buckling Analysis

Linear Buckling Analysis
? Results of interest usually are :
? von Mises Stress for the static load and the deformed buckling shape.

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Chapter 6: Buckling Analysis

Exercise 6.1: 3-D Buckling Analysis
Overview
In this tutorial you will learn the steps required to perform a buckling analysis using RADIOSS. The figure below illustrates the structural model used for this tutorial.

Structural model with static loads and constraints applied.

This tutorial will use the following steps to set up the structural model for a buckling analysis: ? ? Create boundary conditions for buckling analysis Post-process results

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Chapter 6: Buckling Analysis

Exercise 6.1:
Step 1: Launch HM, set the RADIOSS user profile and retrieve the file buckling.hm
1. Launch HyperMesh 2. Choose RADIOSS, (Bulk Data Format) in the User Profile dialog and click OK. This loads the user profile. It includes the appropriate template, macro menu, and import reader, paring down the functionality of HyperMesh to what is relevant for generating models in Bulk Data Format for RADIOSS and OptiStruct. The User Profiles… GUI can also be accessed from the Preferences pull-down menu on the toolbar. Select the optimization panel on the Analysis page 3. From the File pull-down menu on the toolbar, select Open…. An Open file… browser window pops up. 4. Find the bucking.hm file. 5. Click Open The structural model has already been set up to contain the necessary elements, parts, property, and material data.

Step 2: Create load collectors
Create three load collectors (SPC, Static load and Buckling load) and assign each a color. Follow these steps for each load collector. 1. Right click inside the Model Browser window and activate the menu over Create and click LoadCollector 2. In the Name: field type SPC. 3. Leave Select type: field to None. 4. Select a suitable color. 5. Leave Card image: field to None. 6. Click on Create 7. Similarly create a LoadCollector called Static load 8. Create a LoadCollector with the Name: Buckling loads. 9. Set the Card image: EIGRL 10. Select a suitable color. 11. Click on Create/Edit. 12. Click V1 and leave the default value of 0.0 13. Click ND to edit the field, type in a value of 2 in the text box, and press enter. This tells RADIOSS you would like to extract the first two buckling modes.

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14. Click return to leave the panel

Step 3: Create loads and boundary conditions for the model
For the nodes in the following figure that show constraints, we need to create these constraints and assign them to the spc load collector as outlined in the following steps. 1. From Model Browser expand LoadCollectors, right click on SPC, and click on Make Current

2. From the Analysis page enter the constraints panel. 3. Select all of the nodes on the bottom face of the beam as shown in the following figure. (nodes: on Plane)

Nodes to be selected for constraint boundary conditions.

4. Deselect the degrees of freedom dof4 through dof6. 5. Make sure the load types is set to SPC. 6. Click the green create button to create the necessary boundary constraints. 7. Click return 8. From Model Browser expand LoadCollectors, right click on Static_Load, and click on Make Current 9. From the Analysis page enter the forces panel. 10. Select all of the nodes on the top face of the beam as indicated in the figure below.

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Nodes selected for application of static forces.

11. Set magnitude= to -10000. 12. Click the selector beside N1, N2, N3 and choose z-axis. 13. Make sure the load types is set to FORCE. 14. Click create. the forces should appear. 15. Click return.

Step 4: Create a RADIOSS loadstep (Also sometimes called subcase)
The last step in establishing boundary conditions is the creation of a subcase. 1. From the Analysis page, click loadsteps to enter the panel. 2. Click name=, type Linear, and press ENTER. 3. Set the type: as linear static. 4. Check the box preceding SPC. 5. An entry field appears to the right of SPC 6. Click on the entry field and select SPC from the list of load collectors. 7. Check the box preceding Load and select Static Load from the list of load collectors. 8. Click Create. A RADIOSS subcase has been created which references the SPC in the load collector SPC and the forces in the load collector Static_load. 9. Click name=, type Buckling, and press ENTER. 10. Select type as linear buckling. 11. Check the box preceding SPC. 12. An entry field appears to the right of SPC 13. Click on the entry field and select SPC from the list of load collectors.

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14. Check the box preceding METHOD(STRUCT) and select Buckling_ Load from the list of load collectors. 15. Check the box preceding STATSUB and select Linear from the list of load collectors.
A STATSUB card allows for the selection of a linear static subcase for buckling analysis.

16. Click Create. 17. Click return to go back to the Analysis page.

Step 5: Run both the linear and buckling analysis
1. Select the RADIOSS panel on the Analysis page. 2. Click save as… following the input file: field. A Save file… browser window pops up. 3. Select the directory where you would like to write the RADIOSS model file and name your input file (buckling.fem, for example) and click Save. 4. Set the export options: toggle to all. 5. Click the run options: switch and select analysis. 6. Set the memory options: toggle to memory default. 7. Click RADIOSS to launch your job. This launches the RADIOSS job. If the job is successful, you should see new results files in the directory where HyperMesh was invoked. The buckling.out file is a good place to look for error messages that will help you debug your input deck if any errors are present. The default files that will be written to your directory are: buckling.h3d HyperView binary results file. buckling.res Results file which contains everything from displacement to stress results that can be viewed in the Post page within HyperMesh. buckling.out ASCII based output file of the model check run before the simulation begins and gives some basic information on the results of the run. buckling.sta Detailed breakdown on the CPU time used for each significant t stage in the analysis.

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Exercise 6.2: Post process the results in HyperView
RADIOSS will give you contour information for all of the loadsteps that were run. This section describes the process for viewing those results in HyperView.

Step 1: View results of Linear Loadstep: von Mises contour stress
1. From the RADIOSS panel, click on HyperView. HyperView launches with the buckling.h3d file which contains the model and the results. 2. Click in the bottom of the GUI to activate the Load Case and Simulation Selection dialog. 3. Select Subcase 1 – linear, listed under Load Case (shown below) and click OK.

4. From Graphics pull down menu click on Contour. Choose Element Stresses (2D and 3D) as the Result type and select the sub type to von Mises. 5. Click Apply. This should show the contour of von Mises stress.

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Step 2: View results of Buckling Loadstep: Deformed shape and Animating Results
1. Click Clear Contour from Display Control panel 2. Click on the” >” at the bottom of the Load Case and Simulation Selection to activate the Subcase 2 – Buckling and make sure the simulation is for Mode 1

3. Click the Deformed panel toolbar button 4. Under Result Type: select Buckling mode (v) 5. Under Deformed shape:, enter a value of 10 6. Under Undeformed shape:, for Show:, select Wireframe from the drop down list

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7. Toggle the Stoplight Icon 8. Click the Modal Icon to view the animation

to choose Modal

Similarly we could check the results for the 2nd mode 9. Click the Modal Icon again to stop the animation.

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