Numerical simulation and experimental validation of the microindentation test applied to bulk elastoplastic materials. http://dx.doi.org/10.1088/0965-0393/20/4/045007

Abstract

The main objective of this work is to compare numerically simulated load–indentation depth curves together with deformation and stress fields underneatha sharp indenter for a set of mystical materials. Firstly, a numericalsimulation and experimental validation of the microindentation test appliedto three different bulk elastoplastic materials (copper, stainless steel and purealuminium) using two indenters (Berkovich and spherical) are presented. Thesimulation of these microindentation tests is carried out using the finite elementlarge strain elastoplastic and contact models. The corresponding results areparticularly aimed at addressing the following aspects: the influence of theindenter geometry on both the load–indentation depth curve and range of plasticstrains involved in the test, the comparison of the 3D results for the sharpindenter with those of the 2D approximation, the capabilities of the modellingthrough experimental validation of the numerical predictions and, in addition,an assessment of the indentation size effect. Secondly, the numerical results ofBerkovich indentation applied to a set of mystical materials are exhaustivelydiscussed. Although it is effectively shown that these mystical materials exhibitindistinguishable load–penetration depth curves during the loading phase, animportant aspect that has not been previously addressed is that some cleardifferences in their responses are obtained for the unloading stage. Finally, thedeformation and stress contours at the maximum indentation force and afterunloading are particularly analysed.