The Dc Electrical Potential Method for the Measumment of Fretting Cracks

Abstract

As fretting fatigue cracks are initiated at an early stage of life, the fretting fracture process is dominated by the stable growth of cracks. Hence the measurement of crack length is very important. This paper demonstrates the suitability of the DC potential drop technique for the measurement of fretting cracks. A calibration has been established for monitoring crack growth in BS L65 copper aluminium alloy and an example of fretting crack measurements is presented in the form of crack length versus number of cycles and also crack growth rate versus crack length. The former shows that 80% of the specimen life is spent in crack growth.