MSC.Nastran 2003 - Department of Aerospace Engineering at METU

735 Pages·2004·12.1 MB·English

MSC.Nastran 2003
Linear Static Analysis
User’s Guide
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C O N T E N T S
MSC.Nastran Linear Static Analysis User’s Guide
MSC.Nastran Linear Static Analy-

sis User’s Guide
Preface (cid:1) About This Book, xii
(cid:1) List of MSC.Nastran Books, xiii
(cid:1) Technical Support, xiv
(cid:1) Internet Resources, xvii
(cid:1) Permission to Copy and Distribute MSC Documentation, xix
1
Introduction (cid:1) Introduction, 2
(cid:1) Scope, 3
(cid:1) Using the Finite Element Method, 4
(cid:1) A Simple Problem, 11
2
Organization of (cid:1) Introduction to Organization of MSC.Nastran Files, 20
MSC.Nastran Files
(cid:1) Overview of the MSC.Nastran Input Files, 21
❑ The NASTRAN Statement, 23
❑ File Management Section, 23
❑ Executive Control Section, 23
❑ Case Control Section, 23
❑ Bulk Data Section, 24
(cid:1) Overview of the MSC.Nastran Output Files, 27
(cid:1) The Executive Control Section, 32
(cid:1) The Case Control Section, 34
(cid:1) The Bulk Data Section, 41
3
Grid Points, Scalar (cid:1) Introduction to Degrees of Freedom, 48
Points, and
(cid:1) Grid Points, 49
Coordinate
Systems (cid:1) Scalar Points, 51
(cid:1) Coordinate Systems, 52
❑ User-Defined Coordinate Systems, 54
❑ CORD1R and CORD2R Bulk Data Entries, 54
❑ CORD1C and CORD2C Bulk Data Entries, 58
❑ CORD1S and CORD2S Bulk Data Entries, 59
❑ The Element and Material Coordinate System, 62
4
MSC.Nastran (cid:1) Introduction to MSC.Nastran Elements, 66
Elements ❑ Scalar Elements, 66
❑ One-Dimensional Elements, 66
❑ Two-Dimensional Elements, 67
❑ Three-Dimensional Elements, 68
(cid:1) Scalar Elements, 69
(cid:1) One-Dimensional Elements, 73
❑ The CROD Element, 73
❑ The CBAR Element, 77
❑ PBARL -- An Alternate and Convenient Method for Defining Bar Cross
Sections, 87
❑ The CBEAM Element, 103
❑ PBEAML-- An Alternate and Convenient Method for Defining CBEAM
Cross Sections, 113
(cid:1) Two-Dimensional Elements, 127
❑ The CQUAD4 and CTRIA3 Elements, 127
❑ The CQUAD8 and CTRIA6 Elements, 139
❑ Shell Element Force, Stress, and Strain Output in the Material Coordinate
System, 140
❑ Input, 141
❑ Output, 141
❑ Guidelines and Limitations, 142
❑ The CQUADR and CTRIAR Elements, 142
❑ The Shear Panel Element (CSHEAR), 143
❑ Two-Dimensional Crack Tip Element (CRAC2D), 145
(cid:1) Three-Dimensional Elements, 148
❑ The CHEXA, CPENTA, and CTETRA Elements, 148
❑ The CTRIAX6 Element, 152
❑ Three-Dimensional Crack Tip Element (CRAC3D), 153
(cid:1) CBUSH Elements, 156
(cid:1) The GENEL Element, 160
(cid:1) CWELD Connector Element, 165
❑ Introduction, 165
❑ Connectivity Definition, 165
❑ Property Definition, 168
❑ Finite Element Representation of the Connector, 169
❑ Results Output, 170
❑ Example (CWELD101a-b.DAT), 171
❑ Guidelines and Remarks, 174
5
Material Properties (cid:1) Introduction to Material Properties, 178
and Composites
(cid:1) Isotropic Material (MAT1), 179
(cid:1) Two-Dimensional Anisotropic Material (MAT2), 181
(cid:1) Axisymmetric Solid Orthotropic Material (MAT3), 182
(cid:1) Two-Dimensional Orthotropic Material (MAT8), 183
(cid:1) Three-Dimensional Anisotropic Material (MAT9), 187
❑ Part 1 -- Develop the Material Matrix, 189
❑ Part 2 -- Verify the Material Matrix, 190
❑ Part 3 - Use the Anisotropic Material in the Actual Structure, 193
(cid:1) The PSHELL Entry, 197
(cid:1) The Composite Element (PCOMP), 199
(cid:1) Equivalent Composite Honeycomb Section, 208
6
Static Loads (cid:1) Introduction to Static Loads, 218
(cid:1) Loads on Grid Points and Scalar Points, 219
(cid:1) Distributed Loads on Line Elements, 223
(cid:1) Distributed Loads on Surfaces, 230
(cid:1) Gravity and Centrifugal Force (GRAV, RFORCE), 234
❑ Defining Mass in Your Model, 236
(cid:1) Initial Strains (DEFORM), 241
(cid:1) Load Combinations, 245
(cid:1) Thermal Loads, 249
❑ Using the SUBCOM with Thermal Loads, 249
7
Constraints (cid:1) Introduction to Constraints, 259
(cid:1) Single-Point Constraints, 260
(cid:1) Automatic Application of Single-Point Constraints (AUTOSPC), 263
(cid:1) Enforced Displacements at Grid Points (SPCD, SPC), 267
(cid:1) Multipoint Constraints, 271
(cid:1) Contact Problem Using Linear Static Analysis, 275
❑ Introduction, 275
❑ Input, 275
❑ Output, 276
❑ Limitations, 276
❑ Examples, 277
8
R-Type Elements (cid:1) Introduction to R-Type Elements, 286
(cid:1) Description of the R-Type Elements, 287
(cid:1) The RBAR Element, 290
(cid:1) The RBE2 Element, 297
(cid:1) The RBE3 Element, 301
9
Modeling (cid:1) Introduction to Modeling Guidelines, 312
Guidelines
(cid:1) Choosing the Right Element, 313
❑ General Guidelines, 313
❑ Zero-Dimensional Elements, 313
❑ One-Dimensional Elements, 314
❑ Two-Dimensional Elements, 314
❑ Shell Normals, 316
❑ Remarks and Recommendations, 318
❑ Three-Dimensional Elements, 318
❑ R-Type Elements, 319
(cid:1) Mesh Density, 320
(cid:1) Mesh Transitions, 327
❑ Transition from a Coarse Mesh to a Fine Mesh, 327
❑ Mesh Transition Between Dissimilar Element Types, 336
❑ Shell-to-Solid Transition Element (RSSCON), 338
(cid:1) Grid Point Stresses, 349
❑ Description of the Grid Point Stress Method, 351
❑ Topological Method - Plate Elements and Solid Elements, 352
❑ Treatment of Exception Points, 356
❑ Grid Point Stress User Interface, 357
(cid:1) Consistent Loading, 360
(cid:1) Symmetry, 363
❑ User Interface, 365
10
Model Verification (cid:1) Introduction to Model Verification, 370
(cid:1) Preprocessor Checks, 371
❑ Shrink Plot, 371
❑ Hidden Line/Shaded Plots, 372
❑ Free Edge/Face, 373
❑ Zipper Effect, 374
❑ CBAR/CBEAM Orientation and Offset Check, 375
❑ Duplicate Grid Points/Elements, 375
❑ Properties/Material Plots, 375
❑ Consistent Plate Normals, 375
(cid:1) Strain Energy Output, 379
(cid:1) Diagnostic Tools, 386
❑ Element Summary Output, 387
❑ Element Geometry Checks, 387
❑ Weight Center of Gravity and Moment of Inertia Check, 395
❑ Mechanisms and Singularities, 397
❑ Applied Loads Check, 400
❑ Reaction Load, 402
❑ 1g Load, 403
❑ Output of Maximum, Minimum Grid Point-Based Responses, 403
❑ Unconstrained Equilibrium Check, 409
❑ Automatic Identification of Unintentional Grounding, 410
❑ Thermal Equilibrium Check, 412
❑ Grid Point Force Balance, 412
(cid:1) Stress Error Estimators, 418
❑ Grid Point Stress Discontinuities, 419
❑ Element Stress Discontinuities, 423
❑ Discussion of Error Measures, 425
❑ User Interface, 426
(cid:1) Postprocessor Checks, 428
❑ Summary, 433
11
Inertia Relief (cid:1) Introduction to Inertia Relief, 436
(cid:1) Description of Inertia Relief Using PARAM,INREL,-1, 437
(cid:1) Implementation of Inertia Relief in MSC.Nastran Using PARAM,INREL,-1, 438
(cid:1) Automatic Inertia Relief, 451
❑ Limitations for the Automatic Inertia Relief Method, 452
12
Matrix Operations (cid:1) Introduction to Matrix Operations, 456
(cid:1) Set Definition, 457
❑ The Global Displacement Set, 457
❑ Subsets of the Global Displacement Set, 457
(cid:1) Static Condensation (Guyan Reduction), 462
❑ User Interface, 463
(cid:1) Direct Matrix Input, 471
❑ DMIG, 472
❑ DMIG Bulk Data User Interface, 472
❑ DMIG Case Control User Interface, 474
❑ Stiffness Matrix Using DMIG, 475
❑ Mass Matrix Using DMIG, 481
❑ Load Matrix Using DMIG, 481
13
Linear Buckling (cid:1) Introduction to Linear Buckling, 486
(cid:1) Finite Element Approach, 487
(cid:1) Eigenvalue Extraction Method, 493
❑ Inverse Power Method (INV), 493
❑ Enhanced Inverse Power Method (SINV), 493
❑ Lanczos Method, 494
❑ Comparison of Methods, 494
❑ User Interface, 494
(cid:1) Assumptions and Limitations of Linear Buckling Analysis, 497
(cid:1) Examples, 498
❑ Example 1 -- Classical Euler Beam Buckling, 498
❑ MSC.Nastran Results for Example 1, 499
❑ Theoretical Results for Example 1, 502
❑ Example 2 -- Lateral Buckling, 503
❑ MSC.Nastran Results for Example 2, 503
❑ Theoretical Results for Example 2, 507
❑ Example 3 -- Planar Frame Buckling, 508
❑ MSC.Nastran Results for Example 3, 509
❑ Theoretical Results for Example 3, 510
❑ Example 4 -- Buckling of a Stiffened Panel with Transverse Shear
Flexibility, 510
❑ MSC.Nastran Results for Example 4, 511
❑ Theoretical Results for Example 4, 513
❑ Example 5 -- Buckling of a Cylinder Under Uniform Axial Load, 514
❑ MSC.Nastran Results for Example 5, 515
❑ Theoretical Results for Example 5, 517
❑ Example 6 -- Multiple Buckling Analyses in a Single Run, 518
14
Restarts (cid:1) Introduction to Restarts, 522
(cid:1) Types of Restarts, 523
(cid:1) Structure of the MSC.Nastran Input File, 524
(cid:1) User Interface for Read-Write Restart, 525
❑ Cold Start Run, 525
❑ Restart Run, 525
(cid:1) Determining the Version for a Restart, 535
(cid:1) Read-Only Restarts, 537
(cid:1) Mini-Database Restarts, 538
(cid:1) Miscellaneous Applications, 539
❑ Bulk Data Listing, 539
❑ Summary, 539
15
Database (cid:1) Introduction to Database Management, 542
Management
(cid:1) Definitions, 543
(cid:1) MSC.Nastran Database, 544
(cid:1) File Management Section, 545
❑ INIT, 545
❑ ASSIGN, 547
❑ EXPAND, 548
❑ RESTART, 549
❑ DBCLEAN, 550
❑ DBDIR, 551
❑ INCLUDE, 552
(cid:1) Guidelines for Large Problems, 553
❑ BUFFSIZE, 555
16
Cyclic Symmetry (cid:1) Introduction to Cyclic Symmetry, 560
(cid:1) Description of Geometric Symmetry in MSC.Nastran, 561
(cid:1) Mathematical Description of Structural Symmetry, 567
❑ Reflective Symmetry, 567
❑ Axisymmetry, 570
❑ Rotational Symmetry, 572
❑ Dihedral Symmetry, 577
(cid:1) Bulk Data Entries for Cyclic Symmetry, 582
❑ LOADCYN, LOADCYH, and LOADCYT Bulk Data Entries, 585
(cid:1) Case Control Section for Cyclic Symmetry, 589
(cid:1) Axisymmetric Example, 594
A
Glossary of Terms
B
Grid Point Weight (cid:1) Introduction to Grid Point Weight Generation, 614
Generator
(cid:1) Commonly Used Features, 615
(cid:1) Example with Direction-Dependent Masses, 618
C
Summary of Basic
Case Control
Commands
D
Summary of Basic
Bulk Data Entries
E
Output Listing (cid:1) Examples List, 640
F
Parameters
G
Resource
Estimation
H
Generating the (cid:1) Procedures, 682
Cylinder in
MSC.Patran
I
References