Material Laws

A large variety of materials is used in the structural components and must be modeled in stress analysis problems. For any kind of these materials a range of constitutive laws is available to describe by a mathematical approach the behavior of the material.

The choice of a constitutive law for a given material depends at first to desired quality of the model. For example, for standard steel, the constitutive law may take into account the plasticity, anisotropic hardening, the strain rate, and temperature dependence. However, for a routine design maybe a simple linear elastic law without strain rate and temperature dependence is sufficient to obtain the needed quality of the model. This is the analyst design choice. On the other hand, the software must provide a large constitutive library to provide models for the more commonly encountered materials in practical applications.

Radioss material library contains several distinct material laws. The constitutive laws may be used by the analyst for general applications or a particular type of analysis. You can also program a new material law in Radioss. This is a powerful resource for the analyst to code a complex material model.

Theoretical aspects of the material models that are provided in Radioss are described in this chapter. The available material laws are classified in the table below. This classification is in complementary with those of Radioss input manual. The reader is invited to consult that one for all technical information related to the definition of input data.
Table 1. Material Law Descriptions
Group Model Description Law Number in Radioss (MID)
Elasto-plasticity Materials Johnson-Cook (2)
Zerilli-Armstrong (2)
von Mises isotropic hardening with polynomial pressure (3)
Johnson-Cook (4)
Gray model (16)
Ductile damage for solids and shells (22)
Ductile damage for solids (23)
Aluminum, glass, etc. (27)
Hill (32)
Tabulated piecewise linear (36)
Cowper-Symonds (44)
Zhao (48)
Steinberg-Guinan (49)
Ductile damage for porous materials, Gurson (52)
Foam model (53)
3-Parameter Barlat (57)
Tabulated quadratic in strain rate (60)
Hänsel model (63)
Ugine and ALZ approach (64)
Elastomer (65)
Visco-elastic (66)
Anisotropic Hill (72)
Thermal Hill Orthotropic (73)
Thermal Hill Orthotropic 3D (74)
Semi-analytical elasto-plastic (76)
Yoshida-Uemori (78)
Brittle Metal and Glass (79)
High strength steel (80)
Swift and Voce elastio-plastic Material (84)
Barlat YLD2000 (87)
Hyper and Visco-elastic Closed cell, elasto-plastic foam (33)
Boltzman (34)
Generalized Kelvin-Voigt (35)
Tabulated law (38)
Generalized Maxwell-Kelvin (40)
Ogden-Mooney-Rivlin (42)
Hyper visco-elastic (62)
Tabulated input for Hyper-elastic (69)
Tabulated law - hyper visco-elastic (70)
Tabulated law - visco-elastic foam (77)
Ogden material (82)
Simplified hyperelastic material with strain rate effects (88)
Tabulated law - visco-elastic foam (90)
Arruda-Boyce Hyperelastic Material (92)
Yeoh hyperelastic material (94)
Bergstrom-Boyce Nonlinear viscoelastic material (95)
Composite and Fabric Tsai-Wu formula for solid (12)
Composite Solid (14)
Composite Shell Chang-Chang (15)
Fabric (19)
Composite Shell (25)
Fabric (58)
Concrete and Rock Drucker-Prager for rock or concrete by polynominal (10)
Drucker-Prager for rock or concrete (21)
Reinforced concrete (24)
Drucker-Prager with cap (81)
Honeycomb Honeycomb (28)
Crushable foam (50)
Cosserat Medium (68)
Multi-Material, Fluid and Explosive Material Jones Wilkins Lee model (5)
Hydrodynamic viscous (6)
Hydrodynamic viscous with k-ε (6)
Boundary element (11)
Boundary element with k-ε (11)
ALE and Euler formulation (20)
Hydrodynamic bi-material liquid gas material (37)
Lee-Tarver material (41)
Viscous fluid with LES subgrid scale viscosity (46)
Solid, liquid, gas and explosives (51)
Connections Materials Predit rivets (54)
Connection material (59)
Advanced connection material (83)
Other Materials Fictitious (0)
Hooke (1)
Purely thermal material (18)
SESAM tabular EOS, used with a Johnson-Cook yield criterion (26)
Superelastic Law for Shape Memory Alloy (71)
Porous material (75)
GAS material GAS (-)
User material (29~31)