A Comprehensive Study on Optimizing Mechanical Stress, Contact Temperature, and Electrical Contact Resistance

In recent years, several electrical systems have been installed in modern cars in order to satisfy the needs of comfort, security, and performance and to reduce fuel consumption. Consequently, the demand for electrical power increases. One of the major difficulties of the use of power automotive connectors is the increase of their electrical contact resistance in the running time. This paper attempts to fill this gap and discloses the minimisation of the transient electrical contact resistance and contact temperature by experimental and numerical means. The tested contact samples have the sphere/plane contact shape in order to simulate the real contact in the power automotive connectors and were made with high copper alloys. These contact samples were submitted to high currents (100 A) and different contact forces (50 and 100 N ). Minimisation of electrical contact resistance, contact temperature and maximum stress of contact samples made of recent high-copper alloys under high contact forces and electric current was studied in this work with the help of experimental and numerical means. Experimental results showed that the lower transient values of electrical contact resistance and contact temperature correspond to the contact sample made with copper alloy C19210 which is submitted to the highest contact force (100 N). In order to minimize the electrical contact resistance of the contact sample made of copper alloy C19210, finite element models were developed with one contact point and multipoint contacts using a commercial code. The deformation of contact surfaces, numerical transient values of contact resistance and contact temperature were calculated based on the indirect coupling program which is developed by an APDL language. This program can make the coupling between the mechanical and thermoelectric fields and takes into account the elastoplastic behaviour of the material C19210 which is identified by tensile tests. Results showed that the sample with multipoint contact presents a transient value of contact resistance and contact temperature lower than the ones obtained with one contact point, also the maximum mechanical Von Mises stress obtained for the model with multipoint contacts is not only lower than the yield stress of the material C19210 but also lower than the one obtained for one contact point. Therefore, the gain for the model with multipoint contacts was triple.