Application Field
Present guidelines define modeling and validation requirements for numerical airbag models in Radioss with Finite Volume Method (FVM).
- FVM - Finite Volume Method
- FV - Finite Volume
- UP - Uniform Pressure
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Radioss® is a leading explicit finite element solver for crash and impact simulation.
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This manual provides details on the features, functionality, and simulation methods available in Altair Radioss.
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.
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.
A monitored volume is defined with one or more shell (3-node or 4-node) parts.
An "AIRBAG1" time step is estimated into the Engine, but this time step will never control the time step during the run. If that is the case, it means there is a non-physical airbag definition in the input deck.
Present guidelines define modeling and validation requirements for numerical airbag models in Radioss with Finite Volume Method (FVM).
Airbag numerical models are created for the numerical simulation of crash events related to occupant safety problems. Airbag models may differ in the amount of detail and accuracy depending on their intended application.
The reference geometry definition consists of the undeformed element size for all the elements in the airbag. When reference geometry is used, no stress occurs in the material until the element is the same size as its reference size.
The gas generator model should represent all details available in CAD data: gas generator, injector openings, and retainers.
Material for the air inside of the airbag should be specified either through /MAT/GAS/MASS, /MAT/GAS/MOLE or /MAT/GAS/PREDEF.
The nonlinear anisotropic material LAW58 used be used as the airbag material.
In Radioss the standard method for airbag calculation is the Finite Volume Method (FVM).
Each vent hole should be represented as a separate component in the same position as in the CAD geometry.
Porosity of airbag material is modeled by the addition of a porosity card /LEAK/MAT to /MAT/LAW58 card.
External and internal airbag components including inter-chamber voids and void components used for vents should not have any geometrical intersections.
The airbag housing should represent all details available in CAD data.
A folded airbag model with the correct material, property, contact definition, and specified reference geometry should not move before activation of injector.
A uniform pressure run should be performed to make sure that gas dynamic data, injector input, fabric materials, and contacts give physical results.
By using data from a tank test output, it is possible to obtain the temperature and the mass flow of the gas supplied, which can be used as input to Radioss.
The objective here is to provide some guidelines on how to troubleshoot a simulation where the airbag does not deploy properly or crashes because of the airbag.
The Smooth Particle Hydrodynamics method formulation is used to solve the equations of mechanics, when particles are free from a meshing grid.
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.
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This manual provides a list of all the model definition keywords and options available in Radioss.
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This manual provides details on the features, functionality, and simulation methods available in Altair Radioss.
Airbags are modeled as monitored volumes /MONVOL in several different ways.
Present guidelines define modeling and validation requirements for numerical airbag models in Radioss with Finite Volume Method (FVM).
Present guidelines define modeling and validation requirements for numerical airbag models in Radioss with Finite Volume Method (FVM).
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