Materials and contact shape studies for automobile connectors development

In automobile contacts, nominal contact resistance is required with low-cost materials such as copper alloys working in a wide range of currents (1 μA to 50 A) and forces (1 N to several tens of newtons). The contact resistance of materials is studied in the initial state versus load, both in the inserting phase and during fretting motion. A specific test machine has been developed which allows statistical measurements under different initial conditions: base materials, contact shapes, and loads. The main results are the contact resistance law versus load: R_c=k_cF_c ^-n and the insertion force law F_i=k _iF_c^m where the constants k_c, k_i, n, and m are correlated with material resistivity and contact shape characteristics