Analysis of the pressure distribution in spline couplings

Abstract

Spline couplings used in aerospace applications, supporting very high specific power, need an accurate design in order to reduce the weight and to avoid failure mechanisms as fretting fatigue. One of the influence parameters of this kind of phenomena is the pressure distribution on the teeth surface. In this article, the pressure distribution on spline coupling teeth has been investigated by means of analytical approaches and experimental techniques. In particular, the contact pressure distribution between the teeth in axial direction, obtained by means of analytical models available in literature, has been compared with both experimental data and finite element method models. The experimental pressure distribution has been obtained thanks to a special film, capable of changing colour intensity with the pressure variation, and a dedicated software relating the colour intensity to the pressure level. A dedicated workbench has been set-up and a special spline shaft has been created in order to well fit the pressure measurements.