In the PMD system, thermal contact resistance is modeled using a fictitious connector element with zero volume (a foil), which is inserted between isoparametric elements. This type of element can only be used in heat transfer problems.

Thermal contact resistance is defined by the heat flux $\dot q$ across an infinitesimal layer with a temperature difference $\Delta T$ as $$\dot q=\beta\Delta T,$$ where $\beta~[\text{W}/\text{m}^2\text{K}]$ is the reciprocal of the thermal contact resistance of the material (i.e., the thermal contact conductance).

Elements modeling thermal contact resistance are first defined in the name.i1 file, and the value $\beta$ is then assigned to them in the name.iB file. The assignment must be made in the first load case, in the same way as the assignment of other material properties: