High frequency signal transmission across contact interface subjected to vibration induced fretting corrosion

Fretting corrosion is considered to be one of the most common failure mechanisms in electrical contacts for many applications. Micro-scale motion at the contact surface is the major driver of fretting degradation and produces material displacement and transfer. As a result, the buildup of an insulating oxide layer at the contact interface leads to a rapid substantial increase in contact resistance, which is the most common measure for contact performance. However, with regard to the high frequency applications, impedance rather than simply resistance is a more comprehensive and descriptive measure of contact performance. Prior work by the authors has investigated the capacitive characteristics of impedance in degraded contacts, with the observed behavior modeled as resistor capacitor network in parallel. Correlation of the experimental results with simulation studies demonstrated a decreasing level of the contact capacitance as fretting degradation proceeds. In the present work, an experimental study was performed using a simplified connector configuration in order to investigate the impact of contact degradation on high frequency signal integrity. A network model incorporating transmission line and capacitive coupling parameters was developed which relates the contact impedance to the signal loss and distortion. The results are presented and discussed. A high level of consistency between this model and the experimental data was demonstrated.