Fretting in Electrical/Electronic Connections: A Review

In recent years, there has been considerable interest in investigating the effects of fretting, a common problem of significant practical importance that can affect a wide range of electrical equipment incurring costly component replacement and expensive equipment downtime. Fretting is defined as accelerated surface damage occurring at the interface of contacting materials subjected to small oscillatory movements. Two basic conditions for fretting to occur are relative movement or slip and amplitude of motion sufficient to cause the damage. Experimental evidence shows that amplitudes of the order of 10−8 cm (<100 nm) are sufficient to produce fretting [1]. Thus, from a practical standpoint, there appears to be no minimum surface slip amplitude below which fretting will not occur. Although there may be argument as to the upper limit which may still qualify the process as fretting, there is no doubt that in situations where micro-slip prevails, i.e. where slip occurs over only part of the contacting surface, the movement is entirely characteristic of fretting. This problem has been studied by Mindlin [2] who has shown that the minimum slip amplitude for fretting to occur is given by