Altair OptiStruct™

Optimization-enabled Structural Analysis

New Features

Altair OptiStruct continues to grow rapidly as a comprehensive solution for structural analysis and optimization. With a strong focus on accuracy, speed and scalability, and ease-of-use, Altair OptiStruct 2019 adds significant new functionality for nonlinear analysis, detailed output options for improved diagnostics, large scale parallelization through GPU support, and new design criteria and approaches for optimization.


Highlights of the OptiStruct 2019 release include: 


Nonlinear Analysis

  • Nonlinear axisymmetric analysis, including support for elasto-plasticity and large displacement nonlinearity.
  • Combination joints and joint motion via JOINTG.
  • Detailed convergence summary output via the new MONITOR feature.
  • On-the-fly output of composite results for small and large displacement nonlinear analysis.
  • Thinning and thickness output from large displacement nonlinear analysis.
Axisymmetric analysis of a ball joint

Rotor Dynamics

  • Static Analysis: Rotor effect (RGYRO) can be included in static analysis with centrifugal force.
  • Mode tracking is available for rotor dynamics with complex eigenvalue analysis.
  • Rotor Energy from a complex eigenvalue analysis can be requested via the RENERGY output.
Complex mode of an aircraft engine rotor

Vibrations and Acoustics

  • Modal results output from PFMODE: Displacement and strain/kinetic energy results on eigenvectors with large participation identified by PFMODE are directly available in modal frequency response.
  • SPCD can be defined on fluid grids for modal frequency response analysis.
  • Multiple modal spaces are now supported with FASTFR, Altair’s fast frequency response solver.
  • Support for frequency dependent bushings (PBUSHT) has been extended to FASTFR.
  • Virtual fluid (MFLUID) mass is included in the mass summary in the grid point weight generator output.
  • Sound pressure level (SPL) can be output in punch format from a radiated sound (RADSND) analysis.

Fatigue Analysis

  • Default structural SN curves are available for seam welds and spot welds.
  • SN curve for spot weld can be defined based on input stress ratio “R”.


  • New GRID-based free-shape optimization with more flexible shape changes for shells and solids, enabling the nodes to move normal to the surface.
  • Powerflow is available as an optimization response for topology, topography, sizing, and shape optimization.
  • Principal stress/strain responses from frequency response analysis are available for optimization.
  • Multi-Model Optimization (MMO) can now be run using the global search option (DGLOBAL) to improve chances of finding a global optimum. Additionally, the restart option can be applied to an MMO run.
  • Advanced beam cleaning algorithm during lattice sizing optimization to minimize discrepancy between the optimization and re-analysis of lattice structures.
  • Auto-normalization of weighted compliance responses (DOPTPRM,AUTOWGHT,YES): User-defined weights are normalized with the corresponding compliance values at Iteration 0 for each subcase to determine the new weights for each subcase, which are then utilized for the entire optimization.
Surface (grid) based free shape optimization of an oil pan cover

General Enhancements

  • Symbolic substitution: Provides flexibility to modify the input file to use parameterized input to define various data fields across the model.
  • An alternative, Lanczos eigenvalue EIGRL-based inertia relief analysis is now available.
  • Restart is supported for random response analysis to avoid rerunning the frequency response subcase.
  • RBE2GS is now available to define a rigid connection.

Solver Performance

  • GPU support for PCG iterative solver: Providing significant speedup when the PCG solver is recommended, for instance, for linear static analysis with compact solid models, and compliance-based optimization.
  • Multiple GPU support for PCG iterative solver (via -ngpu # run option): Helpful for very large models which otherwise cannot be solved using a single GPU card.

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