Simulation and experimental verification of electrical contact resistance of heavy-duty connectors with axially canted coil springs socket assembly

Minimizing electrical contact resistance is key to enhancing current-carrying capacity and reducing power loss of heavy-duty connectors. In this work, the electrical contact resistance (ECR) of heavy-duty connectors with axially canted coil springs socket assembly is numerically calculated by the commercial finite element simulation software of COMSOL Multiphysics in conjunction with experimental validation. Firstly, the theoretical calculation model of the ECR for heavy connectors is presented. The mechanical contact stress distribution, the contact area profile, and the electrical potential distribution are further obtained based on the electro-mechanical coupled simulation. The simulation results show that the contact spot remains elliptical during insertion with the aspect ratio increasing from 1.77 to 2.97 as the insertion displacement increases. Furthermore, a custom-developed test rig enabling in situ visualization of the contact area, and measurement of ECR and axial mechanical force is designed. Meanwhile, a dedicated image processing algorithm for extracting contact area profile is proposed. Typical variations in the insertion/withdrawal force and the ECR, as well as the contact area profile as a function of insertion displacement are illustrated explicitly. Experimental validation demonstrates good agreement with the numerical model, with deviations of 3.6% for the insertion force, 4.7% for the image-processed contact width, and 2.3% for the calculated contact resistance. These quantitative results confirm the accuracy and feasibility of the proposed simulation and experimental methodology.