Modeling early stage fretting of electrical connectors subjected to random vibration

Fretting corrosion induced by vibration is a topic of major concern for automotive applications, often leading to increased contact resistance and connector failure. Presently, modeling of the behavior of connectors during fretting corrosion is a difficult matter, requiring many parameters, and is generally highly nonlinear in nature. Experimental testing of sample connectors is currently the only practical method of evaluating connector performance; however, testing can be a time-consuming and inexact task. Prior work by the authors studied the fretting behavior of connectors subjected to single frequency vibration. Correlation of experimental results with simulated behavior showed that, for the primary mode of connector interface motion observed (rocking-type motion), the relative moment at the interface was a good indicator of the observed fretting rate. It was also shown that the moment applied as the result of a given excitation level and frequency could reasonably be predicted via simulation. The current work extends this approach to random vibration profiles, which are a more realistic representation of the connector application environment. A simple model is developed which relates the early stage fretting corrosion rate to the threshold vibration levels for the connector, the dynamic characteristics of the connector/wiring configuration, and the vibration profile. A high degree of consistency between this model and the experimental data was demonstrated. Interestingly, regardless of the excitation profile applied to the overall system the existence of a characteristic vibration threshold at the connector interface was observed.