Implementation and applications of a finite-element model for the contact between rough surfaces

Due to the rough nature of real mechanical surfaces, the contact between elastic bodies occurs at several size-scales. Statistical and fractal contact models can take a wide range of roughness wavelengths into account, without additional computational cost. However, deterministic models are more straightforward to understand and easier to extend to more complex cases like contacting bodies that demonstrate elasto-plastic behavior. This paper presents a finite-element model for studying the frictionless contact between nominally flat rough surfaces. Apart from a description of the model implementation, results from a series of calculations corresponding to theoretical and real life applications are included. Numerically generated surface topographies but also roughness measurements from a stylus instrument are used as input for the model. Elastic and perfectly elastic–plastic materials are included in the examples. Among the presented results one can find the distribution of the contact pressure at the interface and diagrams of the real area of contact as a function of the nominal contact pressure.