A three-dimensional finite element model for thermal effect of imperfect electric contacts

There are two phenomena that have significant influence on the behavior of the imperfect electric contacts (ImPEC) region, electric diffusion and thermal effects. This paper presents a three-dimensional (3-D) finite element (FE) model for simulating the thermal effect of ImPEC using contact-area-resistance and a surface heat flux source at the contact interface in terms of local variables. The dependence of the contact-area-resistance is investigated and incorporated into a numerical model used for simulations. A contact resistance experiment was performed to establish two constants that appear in the ImPEC model. The properties of the interface obtained from both the simulation and experimental studies are incorporated into numerical simulations of railgun experiments conducted at Eglin AFB using a C-type armature. The electromagnetic (EM) FE code EMAP3D was used for all of the simulations.