Finite Element Analysis of a Valve Stem Seal

As a precursor to a full leakage study on Valve Stem Seals (VSS), Finite Element (FE) Analyses were carried out using ANSYS 5.2. Two dimensional axisymmetric static models were developed, with the Mooney-Rivlin strain energy function used to describe the nonlinear behaviour of the rubber. For each analysis, elasto-hydrodynamic lubrication was assumed during valve stem reciprocation. Each model featured an alteration to a ‘standard’ design of valve stem seal (known to give excellent performance over its life cycle), the effect of these differences was then investigated. Where possible, physical measurements were made for comparison with the FE results. This research gives a first order approximation, revealing magnitude and direction of seal lip to valve stem contact.