Home
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.
Obsolete
Block Format Keyword Keywords that are still supported, but no longer maintained (*) are considered obsolete.
/FAIL/XFEM_TBUTC (Obsolete)
Block Format Keyword Describes a XFEM (eXtended Finite Element Method) failure model.

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.
  - 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.
    - /ARCH (Obsolete)
      Block Format Keyword Describes the architecture flag.
    - /CAA (Obsolete)
      Block Format Keyword Describes the computation Aero-Acoustic formulation for Eulerian or quasi-Eulerian simulations. Internal forces are computed with finite volume formulation. It improves results for under integrated elements. By default artificial viscosity is canceled, (qa,qb) default values are zero.
    - /FAIL/XFEM_FLD (Obsolete)
      Block Format Keyword Describes a XFEM (eXtended Finite Element Method) failure model.
    - /FAIL/XFEM_JOHNS (Obsolete)
      Block Format Keyword Describes a XFEM (eXtended Finite Element Method) failure model.
    - /FAIL/XFEM_TBUTC (Obsolete)
      Block Format Keyword Describes a XFEM (eXtended Finite Element Method) failure model.
    - /INTTHICK/V5 (Obsolete)
      Block Format Keyword Shell Thickness defined in /SHELL and /SH3N format not taken into account by interface types 7, 10, 11, 18, 19 and 20. This option is used to allow behavior of versions prior to 10.0.
    - /INTER/TYPE20 (Obsolete)
      Block Format Keyword This is a general single surface or surface to surface contact interface.
    - /INTER/TYPE22 (Obsolete)
      Block Format Keyword This interface uses a cartesian cut cell method to model the fluid structure interaction between a Lagrangian surface and a fluid domain.
    - /MADYMO/LINK (Obsolete)
      Block Format Keyword Describes the definition of links to MADYMO's bodies.
    - /MAT/LAW13 (RIGID) (Obsolete)
      Block Format Keyword This material law is used to model part(s) as rigid bodies.
    - /MAT/LAW51 (Iform = 0) (Obsolete)
      Block Format Keyword The material law is based on a diffusive interface technique.
    - /MAT/LAW51 (Iform = 1) (Obsolete)
      Block Format Keyword This material is able to handle up to three elasto-plastic materials (solid, liquid, or gas). The material law is based on a diffusive interface technique.
    - /MAT/LAW51 (Iform = 3) (Obsolete)
      Block Format Keyword This formulation handles Outlet conditions for Multi-Material ALE domain (formulation: I_form = 0, 1, 10 or 11).
    - /MAT/LAW51 (Iform = 10) (Obsolete)
      Block Format Keyword Able to handle up to four materials: Three elasto-plastic materials (solid, liquid, or gas), and one high explosive material (JWL EOS).
    - /MAT/LAW51 (Iform = 11) (Obsolete)
      Block Format Keyword Able to handle up to four materials: Three elasto-plastic materials with polynomial EOS, following the available yield criteria: Johnson-Cook or Drucker-Prager, and one high explosive material with JWL EOS.
    - /MONVOL/AIRBAG (Obsolete)
      Block Format Keyword Describes the airbag monitored volume type.
    - /MONVOL/COMMU (Obsolete)
      Block Format Keyword Describes the airbag with communications monitored volume type.
    - /MONVOL/FVMBAG (Obsolete)
      Block Format Keyword Describes the airbag with FVMBAG type. The input is similar to AIRBAG type.
    - /PERTURB (Obsolete)
      Block Format Keyword Multiply real values (following the defined normal distribution) to shell thicknesses of selected group of part.
    - /PROP/TYPE5 (RIVET) (Obsolete)
      Block Format Keyword Describes the rivet property set.
    - /RIVET (Obsolete)
      Block Format Keyword Describes the rivet or spotweld.
    - /SHFRA/V4 (Obsolete)
      Block Format Keyword Describes the shell formulation.
    - /SPMD (Obsolete)
      Block Format Keyword Sets SPMD parameters for Hybrid Massively Parallel Program (HMPP) computation.
    - /SURF/MDELLIPS (Obsolete)
      Block Format Keyword Defines the interfaces between Madymo ellipsoid surfaces and Radioss models (/INTER/TYPE14 or /INTER/TYPE15).
    - /TH/MODE (Obsolete)
      Block Format Keyword Describes the time history for flexible body local modes.
    - /UPWIND (Obsolete)
      Block Format Keyword Describes the upwind coefficient.
    - Modif Input File
- 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.

View All Altair HyperWorks Help

/FAIL/XFEM_TBUTC (Obsolete)

Block Format Keyword Describes a XFEM (eXtended Finite Element Method) failure model.

Format


(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/FAIL/XFEM_TBUTC/`mat_ID`/`unit_ID`
$γ$		`K`		$σ$ _r		`I`_{fail_sh}	`I`_duct
`a`		`b`

Optional Line


(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
`fail_ID`

Definition


Field	Contents	SI Unit Example
`mat_ID`	Material identifier (Integer, maximum 10 digits)
`unit_ID`	Unit identifier (Integer, maximum 10 digits)
$γ$	Exponent (Real)
`K`	Critical damage integral Default = 10³⁰ (Real)
$σ$ _r	Fracture stress Default = 10³⁰ (Real)	$[Pa]$
`I`_{fail_sh}	Shell failure flag = 1 (Default) Shell is cracked (not deleted), if D ≥ K for one integration point. = 2 For each integration point, the stress tensor is set to zero, if D ≥ K; and shell is cracked (not deleted), if D ≥ K for all integration points. (Integer)
`I`_duct	Ductile-brittle materials flag = 1 (Default) If a ductile material is used = 2 If a brittle material is used (Integer)
`a`	Material parameter (exponent) (Real)
`b`	Material parameter (exponent) (Real)
`fail_ID`	(Optional) Failure criteria identifier 5 (Integer, maximum 10 digits)

Comments

This failure model is available for Shell only.
An element fails once the Tuler-Butcher cumulative damage parameter is greater than the stated critical damage value, K. The damage parameter accumulation is calculated differently for ductile and brittle materials (I_duct = 1 or 2).
For ductile materials, the cumulative damage parameter is:
$D = \int_{0}^{t} {(σ - σ_{r})}^{λ} dt$
Where,

$σ$ _r

Fracture stress

$σ$

Maximum principal stress

$λ$

Material constant

t

Time when shell cracks for initiation of a new crack within the structure

D

Damage integral, another material constant
For brittle materials, the damage parameter is:

$\dot{D} = \frac{1}{K} {(σ - σ_{r})}^{a}$

$σ_{r} = σ_{0} {(1 - D)}^{b}$

$D = D + \dot{D} Δ t$
Current known limitations are:
- /PARITH/ON does not ensure results repeatability, if SPMD > 1; it works in SMP parallel mode only.
- XFEM is currently NOT compatible with either /ANIM/VECT or with /PARITH/OFF.
The fail_ID is used with /STATE/BRICK/FAIL and /INIBRI/FAIL. There is no default value. If the line is blank, no value will be output for failure model variables in the /INIBRI/FAIL (written in .sta file with /STATE/BRICK/FAIL option).