Experimental evaluation of pressure dependent tangential contact stiffness

摘要

The modelling of nonlinear dynamic behaviour of interfaces is of great interest, with one of the main challenges being the provision of reliable friction interface parameters. One of these parameters is the tangential contact stiffness which represents the in-plane compliance at the interface. It is traditionally assumed to be constant, but recent findings in the literature indicate a dependence of the tangential contact stiffness on the normal load. To investigate this behaviour in detail, the 1D friction rig at Imperial College London was fitted with a High-Speed Camera and Digital Image Correlation system to initially validate its accuracy and then investigate the relationship between tangential contact stiffness and contact pressure. A strong increase of contact stiffness at low contact pressure was observed, followed by a saturation of the contact stiffness at higher values. An increase in contact stiffness due to wear was also present, indicating that current modelling approaches may need to be refined.