Effect of vibration on axisymmetric indentation of a model elasto-viscoplastic material

In this study, a series of axisymmetric indentation simulations was carried out for a model elasto-viscoplastic material, plasticine, using the finite element method in order to gain insight into the bulk mechanical now of the material and the interface frictional characteristics for rigid spherical indenters. Experiments were conducted to obtain selected data as a basis for successful validations of the numerical simulations. Subsequently, a validated study of superimposed vibration loading on standard indentation measurements is described, which investigates the effect on interfacial conditions. The results show that the reduction in indentation load by superimposed oscillations may be explained by a combination of stress superposition and friction reduction.