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Radioss Reference Guide
This manual provides a detailed list of all the input keywords and options available in Radioss.
LS-DYNA Input
This manual provides a list of LS-DYNA input files available in Radioss.
*PART
LS-DYNA Input Interface KeywordDefines a part, which combines material and property information.
*PART_SENSOR
LS-DYNA Input Interface KeywordDefine a sensor (*ELEMENT_SEATBELT_SENSOR) to activate or deactivate a discrete beam element part.

Welcome
What's New
View new features for Radioss 2026.
Radioss Overview
Radioss is a leading explicit finite element solver for crash and impact simulation.
Tutorials
Discover Radioss functionality with interactive tutorials.
Radioss User Guide
This manual provides details on the features, functionality, and simulation methods available in Altair Radioss.
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 2026
  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.
- LS-DYNA Input
  This manual provides a list of LS-DYNA input files available in Radioss.
  - *AIRBAG
  - *BOUNDARY
  - *CONSTRAINED
  - *CONTACT
  - *CONTROL
  - *DAMPING
  - *DATABASE
  - *DEFINE
  - *ELEMENT
  - *EOS
  - *HOURGLASS
    LS-DYNA Input Interface KeywordDefine solid and hourglass formulation for 8-node solid elements.
  - *INCLUDE
  - *INITIAL
  - *INTEGRATION_SHELL
    LS-DYNA Input Interface KeywordDefine user-defined through the thickness integration rules for the composite shell element.
  - *INTERFACE_SPRINGBACK
    LS-DYNA Input Interface KeywordDescribes the variables to output in an initial state file or DYNAIN file at the end of the analysis.
  - *KEYWORD
    LS-DYNA Input Interface KeywordThis keyword should always be the first card of the input file. Optionally used with *CONTROL_UNITS card to specify model units.
  - *LOAD
  - *MAT
  - *NODE
    LS-DYNA Input Interface KeywordDefines a node number and nodal coordinates in the global coordinate system.
  - *PART
    LS-DYNA Input Interface KeywordDefines a part, which combines material and property information.
    - *PART_COMPOSITE
      LS-DYNA Input Interface KeywordDefines a part for composite application that contains material and ply information.
    - *PART_SENSOR
      LS-DYNA Input Interface KeywordDefine a sensor (*ELEMENT_SEATBELT_SENSOR) to activate or deactivate a discrete beam element part.
  - *RIGIDWALL
  - *SECTION
  - *SET
- 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
Radioss Example Guide
This manual presents examples solved using Radioss with regard to common problem types.
Radioss Verification Problems
This manual presents solved verification models.
Radioss Frequently Asked Questions
This section provides quick responses to typical and frequently asked questions regarding Radioss.
Radioss Theory Manual
This manual provides detailed information about the theory used in the Altair Radioss Solver.
Radioss User Subroutines
This manual describes the interface between Altair Radioss and user subroutines.

*PART_SENSOR

LS-DYNA Input Interface KeywordDefine a sensor (*ELEMENT_SEATBELT_SENSOR) to activate or deactivate a discrete beam element part.

Format


(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)
*PART_SENSOR
`part_ID`	`SID`	`ACTIVE`

Definition


Field	Contents	SI Unit Example
`part_ID`	Part identifier. (Integer)
`SID`	Sensor identifier. (Integer)
`ACTIVE`	Sensor flag. = 0 Spring element activated when `SID` activates and cannot be deactivated. = 1 Spring element deactivated when `SID` activates and cannot be activated. (Integer)

Comments

The sensor identifier sens_ID and its behavior (ACTIVE) is mapped to the corresponding spring property /PROP/TYPE23 (SPR_MAT).