Specific wear rates of tribosystems always rely on the data obtained from wear experiments. Nonetheless, the events taking place during an experiment may often lead to wide variations and low repeatability of the results. In this work, the authors attempt to take a closer look into the dynamic contact conditions of a dry linearly reciprocating block-on-flat wear experiment. The finite element method and Archard’s wear model are used through COMSOL Multiphysics^® 5.2a and LiveLink^™ for MATLAB^® software to model the wear and study the influence of different conditions of the block surface and alignment of the sample. Changes of the geometry of the block and the contact pressure are quantified for several back and forth motions, using an extrapolation scheme in the wear modelling methodology. The tracking of such changes allow a dynamic overview of how the block contact area and the contact pressure distribution change throughout time. The results show how the assumption of a constant contact area and use of a nominal contact pressure in calculating the wear rate in such experiments can be inappropriate, especially in the presence of roughness and misalignments of the block.

The contact between solids in metal-forming operations often involves temperature-dependent viscoplasticity of the workpiece. In order to estimate the real contact area in such contexts, both the topography and the deformation behaviour should be taken into account. In this work, a deterministic approach is used to represent asperities in appropriately shaped quadratic surfaces. Such geometries are implemented in indentation finite element simulations, in which the indented material has thermo-viscoplastic properties. By creating a database of simulation data, investigations in terms of contact load and area for the specifically shaped asperities allow for an analysis on the influence of the material properties on the load–area relation of the contact. The temperature and viscoplasticity greatly define how much load is supported by a substrate due to an indenting asperity, but the description of the deformation behaviour at small values of strain and strain rate is also relevant. The pile-up and sink-in regions are very dependent on the thermo-viscoplastic conditions and material model, which consequently affect the real contact area calculation. The interplay between carried load and contact area of a full surface analysis indicates the role that different sized asperities play in the contact under different thermomechanical conditions.