Research On Fretting Wear Characteristics And Failure Mechanism Of Contact Material Induced By High Frequency Vibration

Electrical connector is a kind of crucial port component. It is often affected byits working circumstance and condition, especially those used in aerospace system,and these connectors suffer from high frequency vibration which can lead to frettingwear even failure. Previously researches mainly aimed at fretting wear induced bylow frequency from0.01Hz to80Hz. According to this reason, this paper mainlystudied high frequency fretting wear characteristics of contact material of connector,moreover, the effect of current (2A) on the high frequency fretting wearcharacteristics was also taken into account.Contact material of electrical connector fretting test system was built up. Highfrequency vibration between contacts was provided by an electro dynamic shaker.And the signals of contact force and sliding friction force, contact resistance,relative motion during fretting were acquired. These signals were transferred intothe upper computer via signal acquisition circuit to be displayed, saved andanalyzed by the computer.Fretting wear of connector’s contact material induced by high frequencyvibration was tested and studied using this test system. The change laws of frettingwear characteristics with fretting cycles were investigated, and the characteristics ofhigh frequency and low frequency fretting wear were compared. Contacts wereworn with load (2A current) and without load, and the impact of differentfrequencies, amplitudes, initial contact forces of fretting and coating thicknesses onhigh frequency fretting wear characteristics were studied under these two conditionsrespectively.ABAQUS, a nonlinear finite element software, was used to simulate frettingwear of contact material. Contact characteristics of contact pair were simulated andfriction force between two contacts during high frequency fretting was calculatedwith this software in briefly. And then fretting wear was simulated. In thissimulation, dynamic wear process was equivalent to a static contact problem to besimulated, and related mechanical parameters were obtained with the ABAQUS userdefined subroutine UMESHMOTION. Archard’s wear model was used to calculatewear depth. Followed, finite element model was updated by changing position ofthe nodes using the adaptive mesh adjust technique according to the calculatedresults. The effects of amplitude, contact force and frequency of fretting on wearlose were researched in the simulation method mentioned above. At the same time,the mathematical relationships between wear depth and related variables were established.Integrating the results of test and simulation, the failure mechanisms of contactmaterial induced by high frequency fretting wear were studied. The surfacemorphology of fretting spot under different fretting conditions was investigated, andfretting friction mechanism was clarified, then, the differences between frettingfriction force and classic sliding friction force were interpreted. Basis on theseanalyzed results, electrical contact performance degradation process caused by highfrequency fretting was explained. Where after, impact of current on fretting failurewas studied. Summarize all the conclusions, the process models of fretting wearfailure were established.