Multiscale Modeling of Rough Contact Interfaces with Trapped Compressive Liquid Pockets

We introduce a novel numerical model that integrates a Boundary ElementMethod (BEM) code in Fourier space to solve the problem of lubricated fric-tional contact between rough surfaces. This model accounts for scenarios wherethe lubricant quantity is significant yet discontinuous, leading to the formationof trapped compressible lubricant pockets at the contact interface. Additionally,it incorporates the plastic behavior of solid surfaces through a simple plasticsaturation method, enabling comprehensive analysis of contact area, pressure dis-tribution, and variations in friction coefficient across a wide range of conditions,such as lubricant type, density, and surface roughness. Comparison with experiments demonstrates that the developed model can esti-mate the influence of partial lubrication on the friction coefficients duringaluminum sheet deep-drawing with a good level of precision. Notably, the studyreveals the substantial impact of even minor adjustments in lubricant distributionand volume on the friction behavior of aluminum during forming processes.