The models consist of two bodies lying next to each other. Heat transfer and current flow across the gap between the two bodies can take place via gap conductance, gap heat generation, gap radiation, or gap electrical conductance.

We initiate heat and current flow in the first step by applying different constant temperature and electrical potential fields to each solid body. The steady-state fields along both sides of the interface are used to verify the numerical solutions. The gap closes due to thermal expansion of the two bodies. In the second step the top block is displaced relative to the bottom block to generate heat due to frictional sliding. In addition, heat transfer occurs due to gap conductance and gap radiation; and the current flow occurs due to gap electrical conductance. The upper body is displaced back to its original position in the third step. The fourth step is a linear perturbation step, wherein a load of sufficient magnitude to open the gap is applied. In addition, the *CONTACT PAIR, TIED option is verified by defining one of the deformable bodies with this feature. The *SECTION FILE and *SECTION PRINT options are used to output the total force and the total heat and current fluxes across the contact surfaces; the results match the output of similar output quantities obtained using the *CONTACT FILE option.

Young's modulus	30 × 106
Poisson's ratio	0.3
Gap friction	0.01
Density	7700.
Thermal expansion coefficient	10 × 10–6
Conductivity	43.0
Electrical conductivity	43.0
Joule heat fraction	0.0
Specific heat	600.
Gap conductance	1.0
	0.034664
	0.034664
	1.0
	–273.16
	0.5
	0.5
Gap electrical conductance	1.0