.. _materials: Materials =========== General information -------------------- The definition of materials happens in the section ``MATERIALS``. A material model defines its constitutive behavior, which may consist of several terms; however, there is always *one* material assigned to each element. This material can be an explicit material definition on its own, or a collection of behaviours consisting of a number of material models to be defined subsequently. The explicit definition of a material model is in general given by a single line of the form :: MAT One may also define a material by summation of several potentials. A collection of material behaviors, on the other hand, looks like this: :: MAT NUMMAT MATIDS ... Here, the terms of the ```` constitutive behaviors have to follow with their own number, which must correspond to `` ... ``. Structural Material Models -------------------------- A material model in structural mechanics defines the connection between deformation (usually strain) and stress. Many material models are available, including (hyper-)elastic, elasto-plastic, visco-elastic, visco-plastic, and even damage models. If you wish to implement a new material model, this is of course also possible, it is an in-house code after all. You'll find more information on implementing material models in the :ref:`material section` of the developer guide. Fluid Material Models --------------------- Other Material Models --------------------- Coupling Material Models for Various Physics on a Single Discretization ----------------------------------------------------------------------- One may use a single (multiphysics) element type for a multiphysics simulation with matching discretizations. However, since each discretization belongs to a single physics representation and can thus only be connected to a single material, the other material has to be connected to the same discretization by cloning the discretization to the other physics. In |FOURC|, we use a material mapping section, which connects two material models to a single representation. One can see it here in for a simple Thermo-Structure-Interaction problem: :: ----------------------------------------------------------MATERIALS MAT 1 MAT_Struct_ThermoStVenantK YOUNGNUM 1 YOUNG 2.1e08 NUE 0.3 DENS 7.85e-06 THEXPANS 1.1e-05 CAPA 6.445 CONDUCT 1031.2 INITTEMP 273.15 MAT 2 MAT_Fourier CONDUCT_PARA_NUM 1 CAPA 6.445 CONDUCT 1031.2 -----------------------------------------------CLONING MATERIAL MAP SRC_FIELD structure SRC_MAT 1 TAR_FIELD thermo TAR_MAT 2 -------------------------------------------------STRUCTURE ELEMENTS 1 SOLIDSCALAR HEX8 1 2 3 4 5 6 7 8 MAT 1 KINEM nonlinear TECH fbar .. ToDo:: Here we should have a list of the discretizations that can be coupled