NEi Nastran Engine

The NEi Nastran Engine is a powerful, general purpose Finite Element Analysis solver used to analyze linear and nonlinear stress, dynamics, and heat transfer characteristics of structures and mechanical components. NEi Nastran represents the latest in FEA technology with one of the fastest iterative solvers on the market along with accurate solutions that have been trusted for over 15 years by companies in all industries. It is available on a wide variety of platforms including 32-bit and 64-bit Windows, Linux, and Unix operating systems.

Capabilities

Element Library • Tapered beam • Rod and bar • Tube • Pipe • Quadrilateral and triangular plates (6DOF/Node), membranes, shells, shear panels • Solids (four, five, and six-sided up to 20 nodes) • Shear panels • Plane stress, plane strain • Spring, mass, and damper • Coupled spring and damper • Cable element • Initial slack or tension • Failure (snap) • Contact elements (gap, slide line, surface-to-surface) • Surface-to-surface and edge-to-surface weld option for contact surfaces • Offset weld for contact surfaces with significant separation • Spot weld (CWELD) • Rigid general form, rigid rod, rigid bar, and rigid plate • Interpolation • Conduction • Capacitance • Boundary surface • Laminated solid elements (CHEXA, CPENTA) • General elements Solution Capabilities • Linear Static Analysis • Inertial Relief • Thermal Stress and Deflection Analysis • Nonlinear Static Analysis • Geometric nonlinear • Large displacement/rotation (updated Lagrangian) • Follower forces • Snap-through analysis • Displacement control • Material nonlinear • Elastic • Elastic-plastic • Perfectly plastic • Nonlinear elastic • Thermo-elastic • Creep   • Tension-only cables and shell elements with multiple loading condition • Gap, slide line, and surface-to-surface contact with friction • Temperature dependent materials in all solutions • Linear and Nonlinear Buckling Analysis • Natural Frequencies and Mode Shapes • Constrained, unconstrained, and rigid body • Modal participation factors • Modal reaction forces • Effective mass and percent effective mass • Extremely fast blocked Lanzcos and subspace methods • Linear and Nonlinear Direct Transient Response Analysis with adaptive time stepping • Linear Surface Contact Analysis • Direct Frequency Response • Modal Transient and Frequency Response • Modal Response and Shock Spectrum Generation • Dynamic Design Analysis Method, DDAM • Single and multi-phase DDAM operation capability • Modal Summation (NRL, SRSS, ABS, and CQC methods) • Random Vibration   • Correlated and uncorrelated input • Power spectral density • RMS • Autocorrelation input • Force, reaction, displacement, velocity, and acceleration output • Optional maximum and minimum principal stress/strain and von Mises results • Results output for bush elements • Multipoint constraint force output • Vibration Fatigue Analysis   • Life and damage results measures and biaxiality ration from vibration fatigue analysis • Response Spectra Generation • Complex Eigenvalue Analysis • Enforced Motion • Damping supported in all dynamic solutions   • Modal damping   • Equivalent viscous • Fraction of critical • Quality factor • Structural damping • Material damping • Discrete viscous damping elements: CBUSH, CVISC, CDAMP • Raleigh and proportional damping • Nonlinear and frequency dependent damping • Option to force modal damping to be treated as structural damping • Nonlinear shock and vibration mount • • Linear and Nonlinear Prestress   • Dynamic solutions • Static analysis • Buckling analysis • Modal analysis • Transient and frequency response analysis • Random vibration • Response/shock spectrum generation • Modal summation • Linear and Nonlinear Steady State Heat Transfer • Linear and Nonlinear Transient Heat Transfer • Composite laminate materials supported in all solutions • Mass Properties Analysis • Direct Matrix Import and Export (DMIG) for all solutions • Craig-Bampton and Guyan Reduction • Static condensation • Automated Surface Contact Generation (ASCG) • Automated Impact Analysis (AIA) Element Features • Material properties include: temperature and stress dependent isotropic, orthotropic, anisotropic, and laminated composite material models • Robust shell and solid elements give accurate results even with high skew angles, large aspect ratios, and when used in a coarse mesh • Both element and grid point stresses can be output in any coordinate system with one simple command • Automatic mid-side edge node option for solid elements • Automatic vertex drill degree of freedom for shell elements • Automatic correction for improperly defined rigid and interpolation elements • Automatic correction of improperly defined parabolic solid elements • Extensive checkout procedures • Automated internal superelement generation • Automated surface contact and surface weld generation Solution Features • Model size limited by available disk space only • Extremely fast sparse direct and iterative (PCGLSS) equation solvers reduces solution times from hours to seconds • Automatic mass and stiffness singularity detection and correction • Decomposition mechanism detection and correction • Solution error measure for static solutions, orthogonality loss and error norms for eigenvalue solutions • User definable restart capability for nonlinear static analysis

Material Properties • Isotropic • 2D and 3D Orthotropic • 2D and 3D Anisotropic • Temperature-dependent • Stress-dependent  • Creep  • Large strain hyperelastic  • Large strain isotropic  • 2D and 3D composite laminate  • Isotropic and orthotropic plane strain Performance and Control Features • Uses the most current advances in finite element technology • Written in fast, optimized 32-bit Visual Fortran 95 and C/C++ • Complete program control is provided allowing user definable program execution sequence • Multiple model initialization files can be created, each customized for a particular job • Extensive error checking at all stages of execution • Program execution can be tailored to system resources for optimum performance • Support for model input files over 10 million lines in size Output Features • Direct support for results import using either ASCII or Binary neutral file interface • Results import support for other FEA and CAD applications using the NASTRAN Output 2 or PATRAN 2.5 neutral file interface • Support for NASTRAN XDB results neutral files • A detailed tabular model data/results file eliminates the cryptic nature of standard NASTRAN output files by explaining all entities in the model database • Results measures include • Energy • Stresses • Strains • Forces • Reactions • Displacements • Velocities • Accelerations • Heat fluxes • Thermal gradients • Temperatures • Enthalpies • Grid point force balance • Global stiffness matrix • Global conductivity matrixes • Mass and damping matrixes • Solution and mesh error estimates • Element and grid point results • Nonlinear results include   • Equivalent stress • Effective plastic, nonlinear elastic, and creep strain • Gap, slide line, and contact surface displacement • Contact forces and stresses • Automatic and user definable measure sorting for handling multiple load case results • Powerful grid and element set generator for generating sets that can be used to control output, define measure coordinate systems, generate grid point temperatures, and define measure sort commands • Shell and solid element corner stress and strain output • Grid point weight generator with complete mass properties • Stress discontinuity/convergence error calculation • Element and grid point stress, strain, heat flux, and thermal gradients can be output in any coordinate system including: material, grid point, basic, and global • Intermediate bar and beam element output • von Mises stress output for bar, beam, shell, and solid elements • Composite failure index and strength ratio output • Composite sandwich material stability index • Strain energy output for composite shell elements • Von Mises strain output for linear solutions • Automatic generation of structural temperatures for direct modeler import or structural analysis • Element and grid point thermal gradients and heat flux • Heat flow into heat boundary elements • All directional results measures can be output in a user definable coordinate system either before or after an analysis is run • PUNCH file support for real element results data • Support for strain curvature output • Bush element linear strain output • Normalized mesh convergence error measures • Real-time grid point and element results x-y plotting and MS Excel Comma Separated Variable (.CSV) file generation • Inertia relief rigid body acceleration vector output • Thermal, mechanical and total strain output Loads and Boundary Conditions • Nodal forces and moments • Pressure loads • Gravity and centrifugal • Rotational acceleration and velocity • Single and multipoint constraints • Symmetric, antisymmetric, axisymmetric, cyclic symmetric boundary conditions • Multiple loading and boundary condition subcases • Thermal loading and stress recovery • Temperature dependent conductivity • Isotropic and anisotropic thermal conductivity • Temperature dependant internal heat generation • Temperature dependent heat transfer coefficient • Temperature gradient dependent heat transfer coefficient • Radiation and convection loads • Nonlinear functional forms • Surface normal heat flux • Grid point nodal power • 2D or 3D interpolation of input, temperature, displacements, forces, moments and pressure loads • Specified constant temperatures for steady state analysis • Specified time-dependent temperatures for transient analysis • Initial starting temperatures for nonlinear steady state analysis • Initial starting temperatures for all transient analyses • Inertial relief loading Accurate and proven answers • Over 15 years of use by industry • Comprehensive verification program and documentation set • Over 3000 test problems verified for each release • Extensive built-in diagnostics verify accuracy of each analysis Unparalleled support • Leader in outstanding customer support • Onsite and offsite training courses taught by experienced professional engineers • Phone and email support staffed by a team of FEA specialists • Optional consulting services available

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