Scratch-tip-size effect and change of friction coefficient in nano/micro scratch tests using XFEM

Compared to the experimental studies, numerical studies on scratch test have been limited due to the difficulty of numerical modeling. Here, we experimentally investigate the scratch-tip-size effect (STSE) based on coefficient of friction (COF) change to make extended finite element (XFE) models considering STSE, COF change, failure modes, yielding strength, shear strength, elastic recovery and pile-up. XFE models are then validated through nano/micro scratch tests on soda-lime glass. Finally, components of COF are extracted and then effects of tensile cracks and parameters of Drucker-Prager model on COF are investigated. We expect that proposed XFE models contribute to the understanding of damage characteristics during the scratch test.