Standards and legislation concerning valve stem leakage are becoming ever more rigorous in recent years. In the attempt to gain a better scientific understanding of valve packing behaviour a finite element (FE) model of exfoliated graphite packing rings is currently under development. Exfoliated graphite packing rings are porous and display pressure dependent yield behaviour. This behaviour is seen in geotechnical materials, i.e. sand and clay. Material testing to determine the input parameters required for FE modelling have been carried out and subsequent FE modelling is in progress using DIANA and ABAQUS.
展开▼
