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Reference Guide
This manual provides a detailed list of all the input keywords and options available in Radioss.
Starter Input
This manual provides a list of all the model definition keywords and options available in Radioss.
Groups(Sets)
Block Format Keyword Keywords in this group are used to define how to select a group of node, part, elements, lines, or surfaces.
Lines
Block Format Keyword
/LINE/SEG
Block Format Keyword Definition of the line segments.

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.
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 2024
  New and modified features in Radioss.
- Starter Input
  This manual provides a list of all the model definition keywords and options available in Radioss.
  - 2D and 3D Analysis Options
  - Starter Keywords Syntax
    Block Format Keyword
  - 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.
  - Computational Fluid Dynamics (CFD)
  - General Controls
    Block Format Keyword In this group, keywords are used to set default value, global parameter, analysis type, input/output print, damping and ALE and CFD treatment for the whole model. For default value, it is still possible to overwrite in each specific keywords.
  - Nodes
    Block Format Keyword In Radioss, two node types are available. They use Cartesian coordinate to describe the position of each node.
  - Elements
    Block Format Keyword
  - Component and Parts Organization
    Block Format Keyword In this group, keywords are used to combine material and property information (/PART), assemble model (/SUBSET) or define a separate model (//SUBMODEL).
  - Interfaces
    Block Format Keyword Interfaces solve the contact and impact conditions between two parts of a model. Several interface types are available in Radioss and use different contact treatments.
  - Materials
  - Properties
    Block Format Keyword
  - Monitored Volumes (Airbags)
    Block Format Keyword Monitored volumes can be used to model an airbag, tire, tank, or any closed volume.
  - Constraints
    Block Format Keyword Radioss supports several different kinematic constraints, which are mainly used to impose acceleration, velocity, displacement or temperature in structure or constraint the moving of structure. They are mutually exclusive for each degree-of-freedom (DOF). Two kinematic conditions applied to the same node may be incompatible.
  - Load Cases
    Block Format Keyword In Radioss the following load cases are available. Stress/strain as initial state could be considered by modeling, as well as pressure, gravity, and thermal load.
  - Tools
    Block Format Keyword In this group, tools like transformation, frames, skews, and curve are introduced.
  - Groups(Sets)
    Block Format Keyword Keywords in this group are used to define how to select a group of node, part, elements, lines, or surfaces.
    - /GRBEAM
      Block Format Keyword Beam Groups
    - /GRBRIC
      Block Format Keyword Brick Groups
    - /GRNOD
      Block Format Keyword Node Groups
    - /GRPART
      Block Format Keyword Describes the part groups.
    - /GRQUAD
      Block Format Keyword Describes the quad groups.
    - /GRSH3N
      Block Format Keyword Describes the 3 node shell groups.
    - /GRSHEL
      Block Format Keyword Describes the shell groups.
    - /GRSPRI
      Block Format Keyword Describes the spring groups.
    - /GRTRIA
      Block Format Keyword Describes a group of 3 node solid elements.
    - /GRTRUS
      Block Format Keyword Describes the truss groups.
    - /SET
      Block Format Keyword Defines a general entity set which can be referenced by other entities.
    - Boxes
      Block Format Keyword
    - Lines
      Block Format Keyword
      - /LINE/BOX or /LINE/BOX2
        Block Format Keyword Definition of lines inside the box.
      - /LINE/EDGE
        Block Format Keyword Selected edges from given surfaces as lines.
      - /LINE/GRBEAM
        Block Format Keyword Definition of the lines selected from beam groups.
      - /LINE/GRSPRI
        Block Format Keyword Definition of the lines selected from spring groups.
      - /LINE/GRTRUS
        Block Format Keyword Definition of the lines selected from truss groups.
      - /LINE/LINE
        Block Format Keyword Definition of the lines selected from other line groups.
      - /LINE/MAT
        Block Format Keyword Definition of the lines which belong to given materials.
      - /LINE/PART
        Block Format Keyword Definition of the lines which belong to given parts.
      - /LINE/PROP
        Block Format Keyword Definition of the lines which belong to given properties.
      - /LINE/SEG
        Block Format Keyword Definition of the line segments.
      - /LINE/SUBMODEL
        Block Format Keyword Definition of the lines which belong to given submodels.
      - /LINE/SUBSET
        Block Format Keyword Definition of the lines which belong to given subsets.
      - /LINE/SURF
        Block Format Keyword Definition of the lines which belong to given surfaces.
    - Surfaces
      Block Format Keyword
  - Adaptive Meshings
    Block Format Keyword Adaptive Meshing is used in metal forming to divide the element to better describe the geometry. /ADMESH/GLOBAL and /ADMESH/SET are not available for SPMD computation.
  - Output Database
    Block Format Keyword Time histories output for different element groups, section output, or gauge output are described in this group.
  - Obsolete
    Block Format Keyword Keywords that are still supported, but no longer maintained (*) are considered obsolete.
- 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.
- Optimization Keywords
  Optimization Keyword This manual contains the description of the keywords for the Radioss optimization. This manual is compatible with the version 2018 of Radioss.
- Multi-Domain
  This manual contains the description of the keywords for the Radioss Multi-Domain.
- 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.

/LINE/SEG

Block Format Keyword Definition of the line segments.

Format


(1)	(2)	(3)
/LINE/SEG/`line_ID`/`unit_ID`
`line_title`
`seg_ID`₁	`node_ID`₁	`node_ID`₂
`seg_ID`₂	`node_ID`₁	`node_ID`₂
etc	etc	etc
`seg_ID`_n	`node_ID`₁	`node_ID`₂

Definition


Field	Contents	SI Unit Example
`line_ID`	Line group identifier (Integer, maximum 10 digits)
`unit_ID`	Unit identifier (Integer, maximum 10 digits)
`line_title`	Line group title (Character, maximum 100 characters)
`seg_ID`₁, `seg_ID`₂, `seg_ID`_n,	List of segment identifiers (optional) (Integer)
`node_ID`₁	Node identifier 1 for segment (Integer)
`node_ID`₂	Node identifier 2 for segment (Integer)

Comments

Lines are used to define interfaces in 2D analysis and interface TYPE8, TYPE11 and TYPE20 in 3D analysis.
All nodes must belong to a shell, brick, triangular shell, truss, or beam element.