A simplified fretting test methodology for complex shaft couplings

A methodology is offered for the experimental simulation of fretting conditions in complex shaft couplings, using a simple representative specimen/test rig. The geometry and loading conditions of the representative specimen are designed to simulate the contact traction and slip at arbitrary positions along the length of engagement of the spline coupling, as predicted by detailed finite element modelling of the coupling. The representative specimen/test rig design is achieved via an iterative finite element process with feedback from preliminary measurements. The cyclic behaviour of the representative specimen correlates well with the results from a reduced scale aeroengine-type spline coupling. The representative specimen approach can facilitate investigation of damage mechanisms in spline, and other, couplings, particularly fretting fatigue and wear within the contact regions, as well as plain fatigue due to tooth bending along the tooth fillet, thus offering an economical approach to the development and testing of spline couplings.