Abstract: In view of the problems of stress relaxation and fretting wear  caused by metal contacts of electrical connectors under alternating  vibration stresses, the contact reliability of electrical connectors might  be reduced.Firstly, the mathematical model of electrical connector  contacts was established.Secondly, vibration test scheme of electrical  connectors and testing circuit were designed,and the tests were carried  out subsequently.During the tests, the contact resistances of the test  specimen increased slowly with the increases of the vibration frequency,  and the fluctuation of the contact resistances was related to the  vibration amplitude and frequency.After the tests, the pore sizes of jacks  increasess and the values of insertion and withdrawal forces increased or  decreased.It is concluded that the stress relaxation phenomenon in the  jacks and fretting wear phenomenon between the contacts of the electrical  connectors are two main factors leading to the contact performance  degradation of the electrical connectors.In addition, the decreases of the  crystal sizes and the increases of the slip line density are the  fundamental reasons for the stress relaxation phenomenon in the jacks of  the electrical connectors.

Key words: electrical connector；vibration；fretting wear；stress relaxation；contact performance degradation mechanism；metallographic , analysis

摘要： 针对电连接器金属接触件在交变振动应力作用下易产生应力松弛及微动磨损现象，从而降低电连接器接触可靠性的问题，建立了电连接器接触件数学模型；设计了 电连接器振动试验方案和测试电路并进行了试验；分析了电连接器的接触性能退化机理。试验中，试品接触件接触电阻随振动次数的增加而缓慢增大，接触电阻的波动量与振幅和频率相关。试验后，电连接器的插孔孔径增大，插拔力有增有减。由此可知：应力松弛和微动磨损现象是导致电连接器接触性能退化的两个主要因素，插孔中晶粒尺寸减小及滑移线密度的增加是插孔出现应力松弛的根本原因。

关键词: 电连接器, 振动, 微动磨损, 应力松弛, 接触性能退化机理, 金相分析