Experimental Study On Fretting Wear And Fatigue Relaxation Of Electrical Connector Contacts Under Vibration Environment

Electrical connectors are widely used in equipment systems as essential components for transmitting electrical signals.Their reliability is determined by the contact parts,which form the core component inside the connectors.However,the performance of these contacts is greatly influenced by vibration stress,which is one of the primary causes of contacts failure in electrical connectors.Therefore,analyzing the performance degradation of electrical connectors under vibration conditions is essential for improving the overall reliability,which can enhance the stability and safety of the equipment system in use.Based on theoretical analysis,simulation,and vibration test,the fretting wear and fatigue relaxation of socket springs in electrical connectors were analyzed under vibration conditions.Herein,the YXXP circular aerospace electrical connector was specifically selected as the research object.The findings provide valuable insights and a research methodology for the design and optimization of electrical connectors to enhance their reliability under vibration conditions.Firstly,the major and minor axis parameters of the elliptical contact surface are calculated using the Hertz contact theory.The deformation method of the semi-infinite plane subjected to distributed forces is employed,along with complete elliptic integral equations of the first and second kind and the contact deformation coordination equation,which are in good agreement with subsequent finite element simulations and experimental test results.Moreover,based on the Holm electrical contact theory and GW contact model,the roughness surface density and probabilistic columnar functions are introduced to establish a theoretical model of electrical contact resistance and analyze the influence of the variables in the model.And a socket spring cantilever beam model is introduced to establish the initial electrical contact resistance model of the initial closing amount(deflection)of the socket springs.Simulation by sine vibration were conducted to observe the relative displacement changes of the contacts under different amplitudes.Sine vibration tests were designed and conducted to analyze various parameters such as electrical contact resistance,socket springs diagonal distance(opening diameter),plug shell acceleration signals,and pin contact surface micromorphology.The goal was to understand the mechanism behind the changes in electrical contact resistance and fretting wear under vibration conditions.The findings revealed that the installation directions considerably impacted the performance degradation of the electrical connectors,particularly in transversely arranged joints where wear adversely compromised the electrical contact performance.Based on experimental test data and the initial electrical contact resistance model,the calculated optimal interval of the initial closing amount of the socket springs,which provides a reference for the reliable design of the contacts.The finite element model was developed considering the electrical connector assembly relationship and contact connection.This model enabled the determination of von Mises stress power spectral density at the root of the springs under varying levels of vibration through random vibration simulation analysis using Hyper Mesh and ANSYS.Subsequently,the time-domain load history at the root of the socket springs was calculated using a non-uniform discrete Fourier inverse transform.By employing the random load cycle counting method,a two-dimensional joint probability distribution function of stress mean and amplitude,along with an equivalent load model,was established considering the pre-stress imposed at the root of the socket springs.The cumulative fatigue damage variation of the socket springs with vibration time and different magnitudes was determined based on the Miner cumulative damage theory.Finally,through the design and implementation of random vibration tests on the electrical connector,the correlation between the diagonal distance of the springs and the accumulated fatigue damage value was analyzed.The examination of the metallographic tissue revealed plastic deformation near the root of the socket springs,as well as irregular peristalsis of the material at the edge of the root.Furthermore,the strength of the peristalsis gradually decreased from the outer edge to the inner side.These changes became more pronounced with increasing test duration.