AC Signal Modulation on Electrical Contacts due to Vibration Induced Fretting Corrosion

摘要

Fretting degradation is commonly recognized as a major failure mechanism in electrical connectors subjected to severe environmental vibration. Repeated micro-scale motion at the contact interface leads to material displacement, transfer and oxidation of noble metals. As a result, the contact resistance rapidly increases and higher resistance values are found at two ends of the fretting track due to the non-uniform oxide accumulation at the contact area. In addition, the buildup of the insulating layer of corrosion products brings about a capacitance effect between contact surfaces. The impact of the impedance of a stationary fretted contact on signal integrity is mainly observed at the low frequency range. This study focuses on the effects of the dynamics of fretting motion on an AC signal passing through the contact interface. A series of experiments were performed to investigate the characteristics of the contact impedance and the signal distortion at the duration of fretting motion. A simple model was developed to relate the loss and distortion of AC signals to the vibration profile, the fluctuation of contact resistance, and the buildup of contact capacitance. Good correlation between the experimental and modeling data was obtained.