BY R.VIKAS GAUTHAM NO-2009109037

NASTRAN

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. 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.

The

MSC Nastran is the world's most widely used Finite Element Analysis (FEA) solver that helped MSC Software become recognized in 2011 as one of the "10 Original Software Companies". When it comes to solving for stress/strain behavior, dynamic and vibration response and thermal gradients in real-world systems, MSC Nastran is recognized as the most trusted multidiscipline solver in the world. MSC Nastran is built on work done by NASA scientists and researchers, and is trusted for the design of mission critical systems in every industry. Nearly every spacecraft, aircraft, and vehicle designed in the last 40 years has been analyzed using MSC Nastran. In recent years, several extensions to its capabilities have resulted in a single multidisciplinary solver providing users with a trusted solution to simulate everything from a single component to complex assemblies under diverse conditions.

MSC Nastran offers a complete set of linear static and dynamic analysis capabilities along with unparalleled support for superelements enabling users to solve large, complex assemblies more efficiently. MSC Nastran also offers a complete set of implicit and explicit nonlinear analysis capabilities, thermal and interior/exterior acoustics, and coupling between various disciplines such as thermal, structural, and fluid interaction. New modular packaging that enables you to get only what you need makes it more affordable to own Nastran than ever before.

capabilities include: Structural Solutions Efficient Dynamic Analysis Composites Analysis to Validate Materials High performance FEA for Fast Results Multidiscipline Optimization Multiphysics Multidiscipline Solution

MI/NASTRAN is accessed through a standard Windows based interface called MI/Tools. This interface is easy to use with analyses being run with a single click of the mouse. MI/NASTRAN can also be accessed through the command line within a DOS window.

A screen shot of the basic MI/Tools interface is shown below.

NASTRAN is written primarily in FORTRAN and contains over one million lines of code. NASTRAN is compatible with a large variety of computers and operating systems ranging from small workstations to the largest supercomputers. NASTRAN was designed from the beginning to consist of several modules. A module is a collection of FORTRAN subroutines designed to perform a specific taskprocessing model geometry, assembling matrices, applying constraints, solving matrix problems, calculating output quantities, conversing with the database, printing the solution, and so on. The modules are controlled by an internal language called the Direct Matrix Abstraction Program (DMAP). Each type of analysis available is called a solution sequence.

101 - Linear Static 103 - Modal 105 - Buckling 106 - Non-Linear Static 107 - Direct Complex Eigen-value 108 - Direct Frequency Response 109 - Direct Transient Response 110 - Modal Complex Eigen-value 111 - Modal Frequency Response 112 - Modal Transient Response 129 - Nonlinear Transient 144 - Static Aeroelastic Analysis

145 - Flutter / Aeroservoelastic analysis 146 - Dynamic Aeroelastic Analysis 153 - Non-Linear static coupled with heat transfer 159 - Nonlinear Transient coupled with Heat transfer 187 - DDAM 200 - Design Optimization and Sensitivity analysis 400 - Non-Linear Static and Dynamic (implicit) (MSC.NASTRAN native, supersedes 106, 129, 153 and 159 - part of MD.NASTRAN) 600 - Non-Linear Static and Dynamic (implicit) (front end to MSC.Marc - part of MD.NASTRAN) 601 - Implicit Non-Linear (ADINA for NX Nastran) 700 - Explicit Non-Linear (LS Dyna plus MSC.Dytran - part of MD.NASTRAN) 701 - Explicit Non-Linear (ADINA for NX Nastran)

System resources can have a profound impact on the type and size of analyses that can be performed with MSC.Nastran. Resources that are too low can result in excessive time to complete a job or even cause a fatal error. The current resource limits on the local computer are obtained with the following command: On UNIX, the resource limits on a remote computer that has MSC.Nastran installed are obtained with:

msc2004 nastran limits msc2004 nastran limits node=remote_computer

MSC.Nastran execution is controlled by a variety of parameters, either keywords or special MSC.Nastran statements, both required and optional. The MSC.Nastran parameters may be specified on the command line, in a command initialization (INI) file, in runtime configuration (RC) files and, for some parameters, from environment variables. The information from these sources is consolidated at execution time into a single set of values. Much of this information is passed to analysis processing in a "control file", built using the templates.

This file is used to define keywords that are to be set whenever the nastran command is executed. Typical keywords in the unconditional sections include the installation base directory and the version of MSC.Nastran. Conditional sections and subsections might include keywords such as "rcmd" and "rsdirectory" in sections that are conditional upon the value of the "node" keyword. UNIX: install_dir/msc2004/arch/nastran.ini At installation time, this name is linked to install_dir/bin/nast2004.ini Windows: install_dir\msc2004\i386\nastran.ini or install_dir\bin\nastran.ini The file used is the first one found.

This file is used to define parameters that are applied to all MSC.Nastran jobs using this installation structure. Many of the parameters that might be specified in the INI file could, alternatively, be specified in this file. UNIX: install_dir/conf/nast2004rc Windows: install_dir\conf\nast2004.rcf Below these,you have architecture,node,user and local RC files.

In addition to the internally defined keywords MSC.Nastran allows users to define their own keywords. There are two classes of user-defined keywords: General keywords. These are intended for use in INI file or RC file conditional section clauses, in user modifications to the run template files (nastran.dmp, nastran.lcl, nastran.rmt or nastran.srv) and, for UNIX, in customized queue commands (submit keyword). PARAM keywords. These are keywords associated with a PARAM name.Using descriptive keywords to set a PARAM value may be more convenient than specifying the PARAM statement in an RC file. Also, keywords are not limited to a maximum of eight characters, as PARAM names are, and may be more descriptive of the action being affected or requested.

NASTRAN is primarily a solver for finite element analysis.It does not have functionality that allows for graphically building a model or meshing. All input and output to the program is in the form of text files. However, multiple software vendors market pre- and postprocessors designed to simplify building a finite element model and analyzing the results. These software tools include functionality to import and simplify CAD geometry, mesh with finite elements, and apply loads and restraints. The tools allow the user to submit an analysis to NASTRAN, and import the results and show them graphically. In addition to pre- and post-processing capabilities, several Nastran vendors have integrated more advanced nonlinear capabilities into their Nastran products.

The following software options, based on NASTRAN original source code are available: MSC.Nastran and MD.Nastran NASTRAN-xMG (acquired by MSC Software) NEi Nastran (A PC/Linux-based version of the original NASTRAN source code) NX NASTRAN (acquired by Siemens PLM) Nastran distributed by the Open Channel Foundation

Currently there are numerous commercially available FEA products, some of them being able to read the NASTRAN input format although not bearing the name NASTRAN. Many of them are listed on CAE and FEA page.(ex: Ansys) NEi Nastran V10.0 was released in May 2010. It incorporates over 85 customer driven enhancements including the following additions: nonlinear composite Progressive Ply Failure Analysis (PPFA), concrete material model, direct enforced motion, bolt preload, enhanced rigid element features, visualization support for various entities, automatic dynamic plots during nonlinear analysis, transparent max/min, and a new look and feel for its Editor tool.