About the material library

The material library in Abaqus is intended to provide comprehensive coverage of both linear and nonlinear, isotropic and anisotropic material behaviors. The use of numerical integration in the elements, including numerical integration across the cross-sections of shells and beams, provides the flexibility to analyze the most complex composite structures.

This section describes how to define materials in Abaqus and contains brief descriptions of each of the material behaviors provided. Further details of the more advanced behaviors are provided in the Abaqus Theory Guide.

Defining materials

Materials are defined by:

A local coordinate system can be used for material calculations (Orientations). Any anisotropic properties must be given in this local system.

Available material behaviors

Material behaviors fall into the following general categories:

  • general properties (material damping, density, thermal expansion);

  • elastic mechanical properties;

  • inelastic mechanical properties;

  • thermal properties;

  • acoustic properties;

  • hydrostatic fluid properties;

  • equations of state;

  • mass diffusion properties;

  • electrical properties; and

  • pore fluid flow properties.

Some of the mechanical behaviors offered are mutually exclusive: such behaviors cannot appear together in a single material definition. Some behaviors require the presence of other behaviors; for example, plasticity requires linear elasticity. Such requirements are discussed at the end of each material behavior description, as well as in Combining material behaviors.

Using material behaviors with various element types

There are no general restrictions on the use of particular material behaviors with solid, shell, beam, and pipe elements. Any combination that makes sense is acceptable. The few restrictions that do exist are mentioned when that particular behavior is described in the pages that follow. A section on the elements available for use with a material behavior appears at the end of each material behavior description.

Using complete material definitions

A material definition can include behaviors that are not meaningful for the elements or analysis in which the material is being used. Such behaviors will be ignored. For example, a material definition can include heat transfer properties (conductivity, specific heat) as well as stress-strain properties (elastic moduli, yield stress, etc). When this material definition is used with uncoupled stress/displacement elements, the heat transfer properties are ignored by Abaqus; when it is used with heat transfer elements, the mechanical strength properties are ignored. This capability allows you to develop complete material definitions and use them in any analysis.

Defining spatially varying material behavior for homogenous solid continuum elements using distributions in Abaqus/Standard

In Abaqus/Standard spatially varying mass density (Density), linear elastic behavior (Linear elastic behavior), and thermal expansion (Thermal expansion) can be defined for homogeneous solid continuum elements using distributions (Distribution definition). Using distributions in a model with significant variation in material behavior can greatly simplify pre- and postprocessing and improve performance during the analysis by allowing a single material definition to define the spatially varying material behavior. Without distributions such a model may require many material definitions and associated section assignments.