Photoelastic measurements and computation of the stress field and contact pressure in a pneumatic lip seal

Abstract

This work regards the analysis of the structural behaviour of a typical elastomeric lip seal for pneumatic cylinders under actual working conditions. In situations of relative motion between the lip seal and the cylinder, coulombian friction is taken into account. The analysis has been carried out by means of both numerical and experimental methods. In particular, the behaviour of the seal with respect to the two contact zones, i.e. between seal and rod and between seal and mounting housing, has been studied. In order to describe the seal stress and strain fields, isoclinic lines and isochromatic fringes have been determined both by means of a two-dimensional finite element model and by reflection and transparent photoelastic methods. The contact pressure between the lip seal and the rod has been computed numerically, with the FEM model and analytically from photoelastic data. The comparisons between experimental and numerical data have permitted numerical model validation.