Indentation Characteristics Using Various Indenters: A Study Based on Laboratory and Numerical Tests

Laboratory and numerical indentations, using wedge-shaped, spherical and blunt indenters, were performed. The laboratory and numerical results agreed well that fluctuations of the indentation force occurred after the peaks. In addition, indentations by the wedge-shaped indenter generated median cracks whereas, for the spherical and blunt indenters, median and lateral cracks formed. We inferred from the numerical study that the fluctuations correlate to the crack propagation. In addition, the subsequently concentrated tensile stress zones are responsible for the generation of the median and lateral cracks, caused by spherical and blunt indenters. However, for the wedge-shaped indenter, the tensile concentrated zone, forming at the early indentation stage, can cause the median crack.