A multilayer nodes update method in FEM simulation of large depth fretting wear

A multilayer nodes update method (MLNUM) is proposed to simulate the fretting wear that goes deeper than the first surface layer of the mesh. In addition to the update of the nodes on the contact surface, the nodes under the surface in a self-defined expanded region will be updated as well. After the wear depth is calculated by using Archard's model, every node in the region will be moved inward along the normal load direction with a distance proportional to the wear depth of its corresponding surface node and linearly decreases from the contact surface. A two-dimensional cylinder-on-flat fretting model is examined in some details. The numerical results indicated clearly that MLNUM is a rather convenient and efficient mesh update method that is capable to obtain fretting wear depths much larger than the characteristic size of the initial mesh. Moreover, as the fretting wear goes deeper, the wear volumes calculated according to two implementation of the work-rate can be quite different. The one using the contact normal pressure leads to larger wear volumes than the one using the contact shear stress. Finally, an example of three-dimensional cylinder-cross-cylinder fretting wear is presented as well to demonstrate how to implement MLNUM in three-dimensional cases.