Most assemblies rely on some form of contact for load transfer. The inclusion of contact within a model necessitates a changing status analysis. Contact analyses can be classified as either static or transient.
- In a static case the contact is always known and present but the contact pressure distribution must be determined through an iterative analysis procedure.
- In transient cases, the contact may or may not be present, requiring sweeps through the model to determine where contacts are present based on deformations and the pressure distributions at the contact locations. A shift boot in a car is an example of transient contact where the shape of the structure, and its contact state, is highly dependent on its position.
In either case, advanced solution methodologies must be employed to accurately capture the structure’s strain state. Proper mesh densities must be chosen so that the pressure distribution can be adequately resolved. Additionally, adaptive time steps usually must be employed during the times that contacts initiate or release to allow converged solutions. PMI has performed a wide range of contact analyses including accurately capturing the Hertzian contact stress between individual strands of wire rope.