Numerical Simulation of Nanoindentation Process on Pre-stressed Ti6Al4V Alloy for Residual Stresses Evaluation

Finite Element analysis can be a valid alternative to expensive, time consuming and destructive experimental tests. However, the reliability of a numerical model needs to be properly verified by a robust calibration and validation method, able to demonstrate the effectiveness of the proposed technique. A topic of considerable scientific interest is the estimation of residual stresses in the engineering field, since the available experimental techniques present a limited range of applications, because of the complexity of measurement as well as problems associated with measurement accuracy and applicability to a broad range of materials. This paper presents the development of a numerical model able to calculate residual stresses due to the effects of machining, using the nanoindentation method. Numerical simulations of indentation tests on stressed and stress-free samples were carried out, calibrated and validated using experiments. Results concerning the presence of residual stresses are presented with a good agreement with the experimental evidences.