Beginning with MSC NASTRAN

What is Nastan and Why is it used?

       Nastran is MSC high end solver. Earlier there was no software like Patran to create Structure Condition and Engineers would type text files known as decks/input files/.bdf/.dat and that would contain all the FEM information of your model that needs to be solved.

       Now we use Patran or Altair HypreMesh  to make these input files. Patran would write a .bdf, send it to MSC Nastran to have solve, MSC Nastran makes result files, and then Patran imports the results for post processing.

       Understand these input codes are necessary in order to handle FEA problems. These codes are the language Nastran uses to solve the problem.

Basic of Nastran Input .pdf

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MSC Nastran Documentation

        


       A list of all the MSC Nastran documentation I know of. Each document is linked below. The Release Guides are marked if they have information on the newest SOL 400 updates for that particular release.

1. MSC Nastran 2012 Release Guide
2. MSC Nastran 2012 Installation and Operations Guide
3. MSC Nastran 2012 Quick Referece Guide
4. MSC Nastran 2012 Getting Started with MSC Nastran User's Guide
5. MSC Nastran 2012 Dynamic Analysis User's Guide
6. MSC Nastran 2012 Linear Static Analysis User's Guide
7. MSC Nastran 2012 Demonstration Problems
8. MSC Nastran 2012 User Define Services
9. MSC Nastran 2012 Design Sensitivity and Optimizatin User's Guide
10. MSC Nastran 2012 Explicit Nonlinear (SOL 700) User's Guide
11. MSC Nastran 2012 Implicit Nonlinear (SOL 600) User's Guide
12. MSC.Nastran 2002 Thermal Analysis User's Guide
13. MSC.Nastran Version 68 Aeroelastic Analysis User's Guide
14. MSC.Nastran 2001 Superelement User's Guide
15. MSC Nastran 2012 DMAP Programmer's Guide
16. MSC.Nastran 2004 Reference Manual
17. MSC Nastran 2012 PAA User's Guide (Pre-Release)
18. MSC Nastran 2012 Loads Management User's Guide (Pre-Release)
19. MSC.Access User's Manual Version 2004
20. MSC.Nastran 2001 Numerical Methods User's Guide
21. MSC.Software EFEA 2012 User's Guide
22. MSC.Software EFEA 2012 Tutorial
23. MSC.Software EBEA 2012 User's Guide
24. MSC.Nastran 2001 Release Guide
25. MSC.Nastran 2004 Release Guide                                    SOL 400
26. MSC.Nastran 2004 r3 Release Guide
27. MSC.Nastran 2005 Release Guide                                    SOL 400
28. MSC.Nastran 2005 r2 Release Guide
29. MSC.Nastran 2005 r2 Release Guide Addendum
30. MSC.Nastran 2005 r3 Release Guide
31. MSC Nastran 2007 r1 Release Guide
32. MSC Nastran 2008 r1 Release Guide
33. MSC Nastran 2010 Release Guide                                     SOL 400
34. MD Nastran 2006 Release Guide                                       SOL 400
35. MD R2 Nastran Release Guide                                           SOL 400
36. MD Nastran R2.1 Release Guide                                        SOL 400
37. MD Nastran R3 Release Guide                                           SOL 400
38. MD Nastran 2010 Release Guide                                        SOL 400
39. MD Nastran 2011 & MSC Nastran 2011 Release Guide      SOL 400
40. MSC Nastran 2012 Release Guide                                      SOL 400

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Capabilities of MSC Nastran

Some of the capabilities in MSC Nastran 

There are numerous, and fortunately this I found this Capability Matrix lists some of the capabilities.

Structural Linear
 ·         Linear Statics

 ·         Normal Modes

Structures Nonlinear
·         Large Strains

·         Large Displacement
·         Nonlinear Materials
·         Buckling
·         Global Adaptive Meshing

Structures Dynamics
·         Direct or Modal Frequency Response
·         Direct or Modal Transient Response
·         Direct or Modal Complex Eigenvalue
·         Linear or Nonlinear Transient
·         Random
·         Aeroelasticity I
·         Aeroelasticity II
·         Flight Loads
·         Rotordynamics

Structures Explicit
·         Crash, Drop Test, and Impact
·         Fluid Structure Interaction
·         SPH
·         LS/Dyna Solver

Thermal
·         Steady-state
·         Transient
·         Conduction
·         Convection
·         Radiation
·         Radiation Superelement
·         Orbital Heating
·         Thermal Contact
·         Coupled Advection
·         Thermo-mechanical coupling

Optimization
·         Design of Experiment (Requires A/Insight)
·         Sizing
·         Shape
·         Topology
·         Topometry
·         Topography

Assembly
·         Linear Contact
·         Nonlinear Contact
·         Glue Contact
·         Bolt Modeling
·         Spot Welds
·         Seam Welds
·         Gaskets

Composites
·         Laminate
·         Honeycomb
·         Textile, Filament, and UD Tape
·         Delamination
·         Failure Criteria
·         Fracture Mechanics
·         Virtual Crack Closure Technique
·         Progressive Failure Analysis (PFA)

Advanced Structures
·         Interior Acoustics
·         Advanced Acoustics (EFEA/EBEA)
·         Exterior Acoustics
·         Open FSI
·         MpCCI Interface
·         Dynamic Design Analysis Method
·         ACMS
·         Superelements
·         Rezoning (Structural Zooming)
·         Creep and Relaxation
·         Adams Integration
·         Shared Memory Parallel
·         Distributed Memory Parallel
·         Symmetry (Cyclic, Plain Strain or Stress)

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Analysing Cantilever Beam 1D & 2D

       The .pdf link given below discuss about the two different method to handle the Cantilever Beam in 1D and 2D meshing.

1D & 2D .pdf

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FEA (Chap 101)

       
       Basic understanding on the Finite Element Method, necessary to handle daily NASTRAN academic Problems

       FEA consists of a computer model of a material or design that is stressed and analyzed for specific results. Modifying an existing product or structure is utilized to qualify the product or structure for a new service condition. In case of structural failure, FEA may be used to help determine the design modifications to meet the new condition.

 How Does Finite Element Analysis Work?

       FEA uses a complex system of points called nodes which make a grid called a mesh. This mesh is programmed to contain the material and structural properties which define how the structure will react to certain loading conditions. Nodes are assigned at a certain density throughout the material depending on the anticipated stress levels of a particular area. Regions which will receive large amounts of stress usually have a higher node density than those which experience little or no stress. Points of interest may consist of: fracture point of previously tested material, fillets, corners, complex detail, and high stress areas. The mesh acts like a spider web in that from each node, there extends a mesh element to each of the adjacent nodes. This web of vectors is what carries the material properties to the object, creating many elements.

Stephin

FEA Note I.pdf

FEA Note II.pdf

NORMAL MODES ANALYSIS

       The Modal Analysis (Normal Mode Analysis; SOL 103) of a Rectangular Plate

• While performing Modal Analysis Make sure you define Material>Density
• And if you want to analyse for a particular frequency Go for "Frequency Response"

Example Problem: Rectangular Plate

       Wiki Says > A normal mode of an oscillating system is a pattern of motion in which all parts of the system move sinusoidally with the same frequency and with a fixed phase relation. The motion described by the normal modes is called resonance. The frequencies of the normal modes of a system are known as its natural frequencies or resonant frequencies. A physical object, such as a building, bridge or molecule, has a set of normal modes that depend on its structure, materials and boundary conditions.

       When relating to music, normal modes of vibrating instruments (strings, air pipes, drums, etc.) are called "harmonics" or "overtones".

       The most general motion of a system is a superposition of its normal modes. The modes are normal in the sense that they can move independently, that is to say that an excitation of one mode will never cause motion of a different mode.

       The concept of normal modes also finds application in wave theory, optics, quantum mechanics, and molecular dynamics.

       A mode of vibration is characterized by a modal frequency and a mode shape, and is numbered according to the number of half waves in the vibration. For example, if a vibrating beam with both ends pinned displayed a mode shape of half of a sine wave (one peak on the vibrating beam) it would be vibrating in mode 1. If it had a full sine wave (one peak and one valley) it would be vibrating in mode 2.

Normal Mode Analysis 1 .pdf

Normal Mode Analysis 2 .pdf

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VERIFYING THE MESH QUALITY

        Now try verifying the mesh quality of the of an object using simple TET mesh.

• You will notice that varying the Mesh size varies the ELEMENT QUALITY.
• If u run a analysis you would also find that the result value keep changing for diff element size.This is due to convergence of the result value

 Example: Mesh Quality Checking 

               

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CREATING SOLID FROM SURFACE (.iges > solid)

       During my preliminary days of work i had this great difficulty to tackle the conversion of .iges file (Initial Graphics Exchange Specification) to Solid , because i use to work much with .model file in my training days.       until i got much familiar with the B-rep option.

       GEOMETRY:: CREATE>SOLID>B-REP

Example problem for B-rep Anchor Geometry

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WHAT, WHO, WHEN

MSC Nastran and Patran is a finite element analysis (FEA) program that was originally developed for NASA in the late 1960s under United States government funding for the Aerospace industry. The MacNeal-Schwendler Corporation (MSC) was one of the principal and original developers of the public domain NASTRAN code. NASTRAN source code is integrated in a number of different software packages, which are distributed by a range of companies.

(courtesy: Wikipedia)

Haii

       The blog is meant to HELP beginners, student and advanced users to tackle daily issues and problem faced while using MSC Nastran & Patran.

       Soon I will attach reliable links and file to simplify your working with MSC Nastran & Patran.

       Stephin