A contact model for electrical contact resistance between a rigid plane and a cylindrical surface

Studies show that the formation of stable electrical contact between a graphite cylinder and a copper electrode is essential for generating a stable heat source in penetration brazing of heating cables. In this regard, a novel numerical approach is developed to investigate the contact mechanics. In this regard, the fractal theory is applied to analyze the effect of different materials and geometrical properties on the contact parameters and obtain an appropriate contact model for the electrical contact resistance. Then the proposed mathematical model is validated through the experiment. Moreover, the heat diffusion process is analyzed. The pre-scale film is used in the experiment to record the contact area between the graphite cylinder and the copper electrode. Obtained results show that the common graphite cylinder is the best candidate to ensure a stable heat source for heating the cable welding. It is found that obtained results from the proposed model have excellent agreement with the experiment. Accordingly, it is concluded that the proposed model is capable of accurately predicting the dynamic characteristics of the contact between the graphite cylinder and the copper electrode in the welding cores of heating cables.