Surface characterization of spline coupling teeth subjected to fretting wear

Splined couplings are mechanical components subjected to fretting phenomena above all when they are working in misalignment conditions and so the teeth surface morphology may change according to the corresponding working parameters (misalignment amplitude, presence of lubrication, etc). Aim of this work is to use the surface roughness to identify the fretting wear damage on spline coupling teeth. Experimental tests have been performed by means of a dedicated test rig, using steel made specimens. Teeth roughness has been measured before and after tests. In order to emphasize the different surfaces status, the measured roughness values have been processed considering both traditional and sophisticated parameters as kurtosis and skewness. The effect of transmitted torque and angular misalignment have been investigated. Preliminary results show that roughness values may change according to the working conditions.