Finite element analysis of elasticplastic solids under Vickers indentation: surface deformation

Finite element modeling has been used to study the development of surface deformation during indentation with a Vickers indenter. A wide range of materials with different elastic modulus and yield stresses are examined. Results show that in a pyramidal indentation process, for a perfectly plastic material, sinkingin during loading can change to pileup in unloading. This phenomenon depends on the elastic modulus to yield stress ratio. Results also show that the amount of pileup cannot be related solely to the strainhardening exponent, as often assumed. Rather, after initially sinkingin at small depths of penetration, the pileup for many materials evolves and increases gradually as the indenter is driven into the material. It is shown that the ratio of the plastic volume radius to the indentation depth is nearly constant during loading and it is a function of the yield stress and the Young modulus. Experimental verification in loading and unloading is carried out with the results of Alcala et al.