Dynamic Behaviour of EHD-contacts using a regularised, mass conserving Cavitation Algorithm

Abstract

The paper deals with the holistic simulation of systems supported in journal bearings, which is demonstrated using the example of a conrod’s big end bearing. For that purpose, primarily the interactions of multibody-, structureand hydrodynamics have to be described. Based on the time integration of the global equations of motions, the non-linear bearing forces in the fluid film and the elastic deformation of the bearings surfaces have to be modelled adequately concerning their mutual influence. The implementation of the elastic structure is carried out by means of a hierarchised, IRS–based1modal reduction in order to represent its eigenbehaviour as realistic as possible and to fulfil the requirement of low computational costs by reducing the number of degree of freedoms. Additionally, the journal bearing is considered by an online solution of the Reynolds equation, whereat the cavitation is handled by a transient acting, mass-conserving algorithm. This is based on the classical Elrod algorithm, but was extended by a regularisation, which enables a faster and more stable solution. Due to the general approach, both mechanical and tribological output quantities are accessible. This provides the possibility to draw a comparison with simpler approaches and to emphasize the benefit of the described procedure.