A reliability model for connector contacts

Connector contacts have a typical end-of-life behavior during accelerated life testing. A model that predicts the change in resistance (ΔR) for an aging contact is developed based on that behavior. The model shows that the duration of accelerated life tests can sometimes be reduced by up to 50%, resulting in substantial time and cost savings. Analysis of the model leads to several unexpected conclusions. For example, the evaluation of contact reliability, using ΔR as a parameter, does not agree with a time-to-failure approach in which each individual contact is assumed to have a specific failure time. The agreement is restored by the use of change in conductance (ΔG) ratios. The use of ΔG by itself leads directly to the conclusion that contact reliability evaluated at some point in a contact´s life explicitly depends on the resistance of the contact when it was put into use