Experimental and theoretical investigation of the asperity flattening process under large bulk strain
In this paper, the flattening of the model asperities under large bulk strain has been experimentally and theoretically investigated. The specimens with two types of model asperities (pyramid-shaped asperity and ridge-shaped asperity) on the top surface are compressed by a flat punch. The measured contact ratios are used to validate the theoretical model. The rigid-plastic finite-element method model is developed to analyse the asperity flattening processes under bulk straining. The results show that the contact ratio increases with bulk strain and the contact pressure for both types of asperities. The ridge-shaped asperity exhibits a higher contact ratio than the pyramid-shaped asperity. The contact ratio also increases with the asperity angles in the presence of large bulk deformation.