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User Guide
This manual provides details on the features, functionality, and simulation methods available in Altair Radioss.
Design Optimization
Optimization in Radioss was introduced in version 13.0. It is implemented by invoking the optimization capabilities of OptiStruct and simultaneously using the Radioss solver for analysis.
Implementation
The optimization functionality in Radioss requires an extra input file apart from the usual Starter and Engine input files.
Run Optimization
The -radopt run option is used to run the <name>.radopt Radioss optimization input file in OptiStruct. OptiStruct then looks for the Radioss Starter and Engine files within the same working directory.

Welcome
What's New
View new features for Radioss 2024.1.
Overview
Radioss^® is a leading explicit finite element solver for crash and impact simulation.
Tutorials
Discover Radioss functionality with interactive tutorials.
User Guide
This manual provides details on the features, functionality, and simulation methods available in Altair Radioss.
- Run Radioss
  The Radioss solver can be executed using different methods described here.
- Explicit Structural Finite Element Analysis
  In this section, available explicit features for different explicit analyses are presented.
- Implicit Structural Finite Element Analysis
- Fluid and Fluid-Structure Simulation
  In this section, fluid and fluid-structure simulation is presented.
- Smooth Particle Hydrodynamics (SPH)
  The Smooth Particle Hydrodynamics method formulation is used to solve the equations of mechanics, when particles are free from a meshing grid.
- Multi-Domain Technique
  The objective of the Multi-Domain technique (also referred to as RAD2RAD) is to optimize the computing performances of large scale Radioss models.
- Design Optimization
  Optimization in Radioss was introduced in version 13.0. It is implemented by invoking the optimization capabilities of OptiStruct and simultaneously using the Radioss solver for analysis.
  - Implementation
    The optimization functionality in Radioss requires an extra input file apart from the usual Starter and Engine input files.
    - Set Environment Variables
      The number of cores used by Radioss during the optimization can be defined using the OptiStruct script options -rnt and -rnp options.
    - Run Optimization
      The -radopt run option is used to run the <name>.radopt Radioss optimization input file in OptiStruct. OptiStruct then looks for the Radioss Starter and Engine files within the same working directory.
    - Optimization Process
      Radioss parses all three decks (optimization, Starter and Engine decks) to construct an optimization model. For each optimization iteration, an updated/optimized Starter file (<name>_rad_s#_i###_0000.rad) and Engine file (<name>_s#_i###_0001.rad) will be written out, where ### is the optimization iteration number.
- Error Message Database
  This section is comprised of error messages in ascending numerical order.
- Engine Error Messages
- Warning Message Database
  This section is comprised of warning messages in ascending numerical order.
Reference Guide
This manual provides a detailed list of all the input keywords and options available in Radioss.
Example Guide
This manual presents examples solved using Radioss with regard to common problem types.
Verification Problems
This manual presents solved verification models.
Frequently Asked Questions
This section provides quick responses to typical and frequently asked questions regarding Radioss.
Theory Manual
This manual provides detailed information about the theory used in the Altair Radioss Solver.
User Subroutines
This manual describes the interface between Altair Radioss and user subroutines.

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Run Optimization

The -radopt run option is used to run the <name>.radopt Radioss optimization input file in OptiStruct. OptiStruct then looks for the Radioss Starter and Engine files within the same working directory.

Use Solver GUI

Set <name>.radopt as Input files and use "-radopt" as option.

To specify the number of SMP cores used by OptiStruct use the -nt option. For Radioss, specify the cores using -rnt and -rnp which are the same as the -np and -nt options when running a Radioss simulation.

Using Solver Scripts (Linux machines): [optistruct@host~]$ $ALTAIR_HOME/scripts/optistruct <name>.radopt -radopt
Using OptiStruct Solver Scripts (Windows machines): [optistruct@host~]$ $ALTAIR_HOME/hwsolvers/scripts/optistruct.bat <name>.radopt -radopt
Using Radioss Solver Scripts (Windows machines): [optistruct@host~]$ $ALTAIR_HOME/hwsolvers/scripts/radioss.bat <name>.radopt -radopt
Using Direct Calls to Executable (Linux machines): [optistruct@host~]$ $ALTAIR_HOME/hwsolvers/optistruct/bin/linux64/<optistruct_executable> <name>.radopt -radopt
Using Direct Calls to Executable (Windows machines): [optistruct@host~]$ $ALTAIR_HOME/hwsolvers/optistruct/bin/win64/<optistruct_executable> <name>.radopt -radopt

The Starter and Engine files (<name>_0000.rad and <name>_0001.rad) should be located in the same directory as <name>.radopt.

For MMO (Multi-Model Optimization) which with MMOCID=1 in /DTPL, then run with the command shown here.

[optistruct@host~]$ $ALTAIR_HOME/hwsolvers/optistruct/bin/win64/<optistruct_executable> -mmo <name>.fem

For example:

Two Load cases need be considered in optimization. Then create Radioss Optimization file <name>.radopt for each load case and create an .fem file (in this example is mmo_topo.fem) as shown below to define MMO. Run MMO with:

[optistruct@host~]$ $ALTAIR_HOME/hwsolvers/optistruct/bin/win64/<optistruct_executable> -mmo –mpi –np 3 –rnt 2  mmo_topo.fem

dtpl_example_mmo_topo — Figure 2.