Developing a new experimental set up to study fretting fatigue behavior under cyclic contact loading

Abstract

The disk slot and blade attachment in the gas turbine engines are operated under both cyclic axial and contact loads simultaneously. In this investigation, a new coupon scale testing apparatus is designed and manufactured to study the fretting fatigue behavior of materials under cyclic contact loads. In this cyclic contact load fretting fatigue device (CCLFFD), a simple synchronized electro-mechanical system is used for generating cyclic contact loads with frequency of 0–200 Hz and magnitude of 0–10 kN. The CCLFFD is well instrumented for adjusting, measuring and online monitoring the contact load frequency, contact load graph, and rotation speed of the servomotors. Repeatability and reliability of the test rig were examined by experiment. The performance of the CCLFFD was verified using the experimental results reported in the literature and also by conducting a number of fretting fatigue tests on Al7075-T6 at different contact load frequencies in this work. The results showed that fretting fatigue was significantly affected by the contact load frequency particularly for high cycle fatigue regime. However, the effect was less important for low cycle fatigue regime and totally insignificant for frequencies higher than 80 Hz.