Effect Of Vibration To Electrical Contact Performance Of Connectors

Vibration is a major external environmental factor which is harmful to reliability of signal connectors and cause fretting fatigue failure. Communication system uses a lot of signal connectors, so the faults happened on connect surface of connectors would directly influent reliability of the system. Between two connector contacts there is not only sliding wear but also fretting wear. Connectors usually use gold-plating as protective plating for the contact surface. So abrasion endurance of gold plating directly determines reliability of contacts. Previous researches always pay attention to the distortion of shape and structure, but ignore the internal contacts failure that caused by vibration. The wearing distance of the surface of some disabled connectors are usually between 200μm and lmm. Amplitude which can affect to contact reliability are always under 200μm or about lmm. But few researches about amplitude which can affect to contact reliability are between 200μm and 1mm. Therefore, in order to improve contact capabilities and increase the reliability of connectors, it's necessary to analyze the invalidation causations, invalidation mechanism and infection factors of disabled connectors which caused by vibration.In this thesis, fretting experiments of different amplitude are completed using Au-Au contact pair (probe and coupon are coated with thin gold-plating) and Ni-Au contact pair (one contact body is gold-plating and the other side is nickel-plating) in several repeating times. Then the paper analyzes and compares the contact resistance and the contact surfaces of different experiment groups. It can be concluded that the influence of amplitude is not a monotonous function to contact resistance and wear degree. There is critical fretting amplitude for causing invalidation most easily. The critical amplitude for Au-Au contact pair is 500μm, but the amplitude for Ni-Au contact pair is 800μm, at which the plating wear is the most serious and Au element in the wear track is the least. The trend is as the similar as invalidation times of contact resistance. Choosing contact material according to real using procedure is better for slowing down fretting wear and increasing contact performance.In study of vibration of pin connectors, outside vibration could cause fretting wear of metal matching inside connectors. The gold-plating contact wearing degree gets the most serious at the average scratch length of 500μm. When outside vibration frequency equals to the natural frequency of connector, the contact performance is the worst. In the same frequency, the larger amplitude the more easily affect to contact performance, so the performance of connector would be worse.Coaxial connector has outer fastening thread protection structure to decrease vibration, so this kind of protective action is researched through vibration environment in this paper. The result is that the outer fastening thread can prove effective protection to reduce the inner fretting fatigue failure. The above research results provide some advices for service life evaluation and reliability analysis in actual vibration environment.