LayeredMaterialInterface

Layer IDs

Foremost, this interface relies on the concept of layer ids, which in Mastodon are defined by a field variable, which is typically an AuxVariable that defines regions within the domain that represent areas where material properties vary (e.g., due to changing soil type). The LayeredMaterialInterface must be supplied the layer id field variable, via the "layer_variable" parameter.

Layer Parameters

When defining a Material object it is often desired to vary the value of a property according to the layer id. This connection between layer id and property value occurs in the input file using the "up-and-down" syntax that is ubiquitous throughout MOOSE.

Firstly, using this interface adds a "layer_ids" parameter, which contains a list that will linked one-to-one with other input parameters. For example, in the input file snippet below two parameters ("shear_modulus" and "density") are to be connected to the corresponding value in the "layer_ids" parameter.

[Materials<<<{"href": "../../syntax/Materials/index.html"}>>>]
  [./linear]
    type = LinearSoilMaterial<<<{"description": "Material for computing the shear wave speed and minimum element size as a function of shear modulus and density.", "href": "../materials/LinearSoilMaterial.html"}>>>
    layer_variable<<<{"description": "The variable providing the soil layer identification."}>>> = layer
    layer_ids<<<{"description": "Vector of layer ids that map one-to-one with the 'shear_modulus' and 'density' input parameters."}>>> = '1980   1949'
    shear_modulus<<<{"description": "Vector of shear modules values that map one-to-one with the number 'layer_ids' parameter."}>>> = '1.35e6 4.25e8'
    density<<<{"description": "Vector of density values that map one-to-one with the number 'layer_ids' parameter."}>>> = '1500   1700'
    outputs<<<{"description": "Vector of output names where you would like to restrict the output of variables(s) associated with this object"}>>> = exodus
  [../]
[]

Within the code layer parameters should be accessed using the "getLayerParam" method that is defined in the LayeredMaterialInterface class. This method returns a reference to a container that is sized according to the number of quadrature points, in similar fashion to MooseVariable for MaterialProperty types, allowing the usage of these layer parameters to be trivial. When the parameters are utilized within the computeQpProperties method they are updated automatically to contain the correct values based on the values of the layer variable at the quadrature points.

The LinearSoilMaterial should be used as a guide for creating new Material objects that require the use of layer parameters. In general, there is a three step process for defining layer parameters. First, the parameter is defined in the validParams function of the object being created.

params.addRequiredParam<std::vector<Real>>("shear_modulus",
"Vector of shear modules values that map one-to-one "
"with the number 'layer_ids' parameter.");
params.addRequiredParam<std::vector<Real>>(
"density",
"Vector of density values that map one-to-one with the number "
"'layer_ids' parameter.");

Second, the parameters are stored as member variables (const MooseArray<Real> &) in the initialization list using the getLayerParam method.

_layer_shear_modulus(getLayerParam<Real>("shear_modulus")),
_layer_density(getLayerParam<Real>("density"))

Finally, the layer parameters are utilized to compute a material property.

_shear_wave_speed[_qp] = std::sqrt(_layer_shear_modulus[_qp] / _layer_density[_qp]);

Documentation

To ensure that documentation for the "layer_ids" parameters is accurate it is required that the documentation string be modified by the parent class using the setDocString. This is done to ensure that some reference to the corresponding parameters is defined. For example, the following is found in the LinearSoilMaterial validParams function.

params.setDocString("layer_ids",