Material properties are made temperature-dependent by specifying them at several different temperatures or by specifying a polynomial curve that describes material values versus temperature. In some cases, a material property can be defined as a function of variables calculated by the app; for example, to define a work-hardening curve, stress must be given as a function of equivalent plastic strain. Material properties can also be dependent on "field variables" (that is, user-defined variables that can represent any independent quantity and are defined at the nodes, as functions of time). For example, material moduli can be functions of weave density in a composite or of phase fraction in an alloy. The initial values of field variables are given as initial conditions and can be modified as functions of time during an analysis. This capability is useful if, for example, material properties change with time because of irradiation or some other precalculated environmental effect. Any material behaviors defined using a distribution in your simulation (such as mass density, linear elastic behavior, or thermal expansion) cannot be defined with temperature or field dependence. However, material behaviors defined with distributions can be included in a material definition with other material behaviors that have temperature and/or field dependence. | ||||||||||||