Nonlinear Dynamics and Contact Mechanics of Electrical Chatter

Electrical chatter, characterized by intermittent spikes in electrical contact resistance (ECR) due to mechanical vibration, presents a significant challenge in engineering applications. Electrical chatter is a perplexing problem because its occurrence can be seemingly unpredictable, and it is often difficult to troubleshoot in engineering applications. A key challenge in understanding electrical chatter is the absence of robust modeling approaches. This study employs three mod- els of increasing complexity to investigate different aspects of electrical chatter. The first model examines a hemispherical Hertzian contact, analyzing ECR varia- tions within a single contact. A 32 full-factorial DOE analysis demonstrates that increasing the damping and stiffness of the structure around the hemispherical contact reduces the number of electrical chatter events that occur in the transient portion of its dynamics. The second model adds complexity by containing multi- ple asperities on an oscillating surface and introducing soft impact and geometric nonlinearities. Non-periodic, non-contact and periodic, contact regimes of chatter are observed, and these are expanded upon with the third model. This final model uses beam elements to describe the flexion of a pin-receptacle contact pair and a modified multiscale rough surface description to generate a new equivalent contact function. This model is statistically compared to experimental data, which is in good agreement for some tests. A key finding is that modal amplification from the electrical connector housing plays a significant role in chatter occurrence.