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Reference Guide
This manual provides a detailed list of all the input keywords and options available in Radioss.
Engine Input
This manual provides a list of all the solution definition keywords and options available in Radioss.
Initial State
Engine Keyword In this group, keywords are used to output different info (like stress, strain, orthotropy direction, temperature, and so on) in a state file (STA-File).
/STATE/SPHCEL/FULL
Engine Keyword Describes the stress state for Smooth Particle Hydrodynamic (SPH).

Welcome
What's New
View new features for Radioss 2025.
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.
Reference Guide
This manual provides a detailed list of all the input keywords and options available in Radioss.
- File Extensions and Formats
  Current Radioss format uses the 12x extension format.
- Single File Input
  This format allows running either Starter or Engine with the same file.
- New Keywords in 2025
  New and modified features in Radioss.
- Starter Input
  This manual provides a list of all the model definition keywords and options available in Radioss.
- Engine Input
  This manual provides a list of all the solution definition keywords and options available in Radioss.
  - Engine Keywords Syntax
  - General Controls
    Engine Keyword In this group keywords are used to generally define the output style, control of computation, damping and ALE setup during the computation.
  - Deletion/Input Modifications
    Engine Keyword In this group, keywords are used for modification (deletion or add options) in Engine.
  - Animation and Post-processing Output Files
    Generates animation files containing results according to the keywords specified. The keywords are specified in the topics within Animation and Post-processing Output Files.
  - Implicit Solution
    Engine Keyword In this group keywords are used for implicit solution. Different implicit solver methods (linear, nonlinear, buckling or quasi-static), different options to control the implicit computation, different implicit time step method and implicit output messages are introduced.
  - Kinematics and Loading
    Engine Keyword In this group, keywords are used to define the kinematic condition (constrain/release rotation or translation DOF) and initial condition (rotational/translational velocity).
  - Time Step
    Engine Keyword In this group, keywords are used to define different time step control (STOP, KILL, CST or DEL, and so on) for different entities (shell, brick, beam, airbag, interface, and so on) during the computation.
  - Initial State
    Engine Keyword In this group, keywords are used to output different info (like stress, strain, orthotropy direction, temperature, and so on) in a state file (STA-File).
    - /DYNAIN/DT
      Engine Keyword Define time output frequency and parts to be written to the state file.
    - /DYNAIN/SHELL/STRAIN/FULL
      Engine Keyword Describes the strain state for shell in LS-DYNA format.
    - /DYNAIN/SHELL/STRESS/FULL
      Engine Keyword Describes the stress state for shell in LS-DYNA format.
    - /STATE/BEAM/AUX
      Engine Keyword Describes the internal variable state for beam.
    - /STATE/BEAM/FULL
      Engine Keyword Describes the internal variable state for beam.
    - /STATE/BRICK
      In this group, keywords are used to output different info (like stress, strain, orthotropy direction, temperature…) for solid element in state file (STA-File).
    - /STATE/DT
      Engine Keyword Define time output frequency and parts to be written to the state file.
    - /STATE/INIMAP1D/Keyword3
      Engine Keyword A state file is written with mapping data as functions (/FUNCT) or generated into a binary file.
    - /STATE/INIMAP2D/Keyword3
      Engine Keyword A state file is written with mapping data as functions (/FUNCT) or generated into a binary file.
    - /STATE/NO_DEL
      Engine Keyword Writes the state file for only non-deleted elements.
    - /STATE/NODE/BCS
      Engine Keyword Boundary conditions for Node. The boundary conditions applied to nodes be written to the state file.
    - /STATE/NODE/TEMP
      Engine Keyword Describes the temperature for nodes.
    - /STATE/NODE/VEL
      Engine Keyword The velocity of a node is written to the state file.
    - /STATE/SHELL
      In this group, keywords are used to output different info (like stress, strain, orthotropy direction, temperature…) for shell element in state file (STA-File).
    - /STATE/SPHCEL/FULL
      Engine Keyword Describes the stress state for Smooth Particle Hydrodynamic (SPH).
    - /STATE/SPRING/FULL
      Engine Keyword Describes the internal variable state for spring elements.
    - /STATE/STR_FILE
      Engine Keyword When writing the state file, /INISHE, /INISH3 and /INIBRI will be written in a separate file which can be asked for being compressed (using GZIP) or not. The state file will then resume to the nodes coordinates and element connectivity.
    - /STATE/TRUSS/FULL
      Engine Keyword Describes the internal variable state for truss.
- LS-DYNA Input
  This manual provides a list of LS-DYNA input files available in Radioss.
- Multi-Domain
  This manual contains the description of the keywords for the Radioss Multi-Domain.
- Obsolete Keywords
  Keywords that are still supported, but no longer maintained (*) are considered obsolete.
- Other Files
- Definition
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.

/STATE/SPHCEL/FULL

Engine Keyword Describes the stress state for Smooth Particle Hydrodynamic (SPH).

Format

/STATE/SPHCEL/FULL

Comments

A block /INISPHCEL/FULL is written into each state file, for each part declared into /STATE/DT.