Numerical and Experimental Analysis of Potential Causes Degrading Contact Resistances and Forces of Sensor Connectors for Vehicles

Faults in vehicle sensor connectors are crucial to the safety of a vehicle. Once the connector is loosened according to the reduction of its contact forces, its electrical contact resistance may be increased, causing unexpected errors in sensor systems. However, such error mechanisms have enormously diverse causes that have not yet been identified. This study proposes a process to analyze the causes influencing the connector contact force and resistance by employing a combination of numerical and experimental methods. Specifically, the causes of variation of contact force are numerically analyzed and their influence on the electrical contact resistance is experimentally studied. Precise 3D models of a commercial vehicle sensor connector are developed based on a 3D tomography, and a 3D finite element (FE) simulation is employed to estimate the connector contact force, considering plastic deformation. After classifying potential causes into three categories, two major factors are selected: manufacturing tolerance occurring during the connector manufacturing process and plastic deformation occurring during the vehicle maintenance process. The factors are observed to substantially reduce the contact force (by ~14.6 or 19%). The impact of the reduced contact force is validated in sequential experiments, and exhibits a nonlinear relationship between the contact force and corresponding contact resistance. In addition, the experiments also consider simulated manufacturing and maintenance factors, and demonstrate an increased contact resistance by the functions of the decreased contact force with minor measurement errors (<; 7.5%).