2024

This manual provides details on the features, functionality, and simulation methods available in Altair Radioss.

In this section, available explicit features for different explicit analyses are presented.

View new features for Radioss 2024.

Radioss^{®} is a leading explicit finite element solver for crash and impact simulation.

Discover Radioss functionality with interactive tutorials.

The Radioss solver can be executed using different methods described here.

An explicit is solved by calculating results in small time increments or time steps. The size of the time step depends on many factors but is automatically calculated by Radioss.

Solids hexahedron and tetrahedron with linear and quadratic interpolation functions are available in Radioss.

The elements HA8, HEPH and BRICK20 can be transformed to solid-shell elements by setting constant the normal stress through the thickness.

The two beam elements available in Radioss are used on one-dimensional structures and frames. It carries axial loads, shear forces, bending and torsion moments (contrary to the truss that supports only axial loads).

The stiffness of the spring can be defined multiple ways with each degree of freedom defined differently.

Isotropic, kinematic or uncoupled spring hardening options can be defined by the hardening flag $\mathrm{H}$ .

Spring TYPE4 is a simple physical spring, physical dashpot or parallel spring and dashpot.

Spring TYPE8 is a six degrees of freedom spring: three translations and three rotations.

Spring TYPE12 is used to model a pulley. When used in a seat belt model, it is defined with three nodes.

Kinematic joints are declared by /PROP/KJOINT. Joints are defined by a spring and two local coordinate axes, which belong to connected bodies.

In Radioss, property TYPE45 is the joint type spring.

This spring is a simplification of spring TYPE13; in which the properties of the spring cross-section are considered to be invariable with respect to Y and Z.

Mesh recommendations in crash worthiness and in Implicit Analysis are covered.

Under-integrated elements are very familiar in crash worthiness. In these elements, a reduced number of integration points are used to decrease the computation time. This simplification generates zero energy deformation modes, called hourglass modes.

Different material tests could result in different material mechanic character.

Composite materials consist of two or more materials combined each other. Most composites consist of two materials, binder (matrix) and reinforcement. Reinforcements come in three forms, particulate, discontinuous fiber, and continuous fiber.

In Radioss, a kinematic condition is a nodal constraint applied to a set of nodes.

Several interfaces are available in Radioss, this section deals with contact interfaces only. Each interface is distinguished with a type number.

Airbags are modeled as monitored volumes /MONVOL in several different ways.

In this section, fluid and fluid-structure simulation is presented.

The Smooth Particle Hydrodynamics method formulation is used to solve the equations of mechanics, when particles are free from a meshing grid.

The objective of the Multi-Domain technique (also referred to as RAD2RAD) is to optimize the computing performances of large scale Radioss models.

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.

This section is comprised of error messages in ascending numerical order.

This section is comprised of warning messages in ascending numerical order.

This manual provides a detailed list of all the input keywords and options available in Radioss.

This manual presents examples solved using Radioss with regard to common problem types.

This manual presents solved verification models.

This section provides quick responses to typical and frequently asked questions regarding Radioss.

This manual provides detailed information about the theory used in the Altair Radioss Solver.

This manual describes the interface between Altair Radioss and user subroutines.

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