Fretting in Electrical Connectors Induced by Axial Vibration

A series of experiments were performed to investigate fretting behavior of electrical connectors subjected to axial vibration input. A random vibration test used to study vibration behavior of the connector systems revealed that multiple transverse modes were excited by the axial input. Through tests with single-frequency vibration inputs, the threshold behaviors at various frequencies for the onset of fretting corrosion were identified. It is demonstrated that the threshold amplitudes are at micrometer scale for these types of connectors. The results also exhibit that the thresholds vary with vibration frequencies, and at the frequency of one mode, the threshold is lowest over the testing spectrum. Threshold amplitudes at this mode of the connector systems with various wiring tieoff lengths were also tested. Based on the understanding of the dynamics of the connector systems, a discrete vibration model was developed to predict the threshold behavior at this mode. The estimated threshold amplitudes correlate well with the experimental results through a parametric best fit of the vibration transfer functions.