If a material property under the Materials branch has a temperature dependence, you have to input the temperature to be used in the Model Input section in the settings window for the node in the physics interface that references the property. It is possible that not all aspects of a material are defined in the same node in the Model Builder tree. For example, if a problem is run with thermal expansion and plasticity, then:

For each of these nodes, there is a Model Input section in the Settings window. Some of these sections may be empty if none of the properties given in that node have a temperature dependence. In general, you have to supply the temperature in all the Model Inputs sections.

As a default, the value of the temperature T is obtained from a Common model input. You can also select User defined to enter a value or expression for the reference temperature locally. This can be done either by explicitly giving a temperature or by selecting a temperature variable from another physics interface.

When the option Common model input is selected in a physics node, you can see or modify the value actually used by clicking the Go To Source button (). Doing that will move you the node in the Model Builder that is defining the value of the property. That location can be:

If you want to create a model input value which is local to your current selection, click the Create Model Input button . This will create a new Model Input node under Definitions->Shared Properties in the current component, having the same selection as in the current node.

The preservation of mass requires that the mass density is constant. In a structural mechanics problem this means that the mass density must not change. If you are using a material in which the density has a temperature dependence, you must specify a specific temperature at which the value is evaluated. This is the volume reference temperature. Conceptually, you can consider this as the temperature at which the domain has the size in which it is drawn. In practice, the choice of reference temperature is seldom an issue, unless your application requires extreme precision. The density of a solid material has a rather slow variation with temperature, so in most cases it is sufficient to use room temperature as reference.

If any material in the model has a temperature dependent mass density, the Volume reference temperature list will appear in the Model Input section of the material settings. As a default, the value of Tref is obtained from a Common model input. You can also select User defined to enter a value or expression for the reference temperature locally.