An effective experimental-numerical procedure for damage assessment of Ti6Al4V

A numerical model relying on triaxial and deviatoric levels of stress is used to describe ductile damage accumulation in the Ti6Al4V alloy. To this purpose, an experimental campaign is carried out on a reasonably limited set of tests: tensile tests on smooth and notched cylindrical bars, plane strain tensile tests on flat specimens, and torsion tests. For all of them, FEA analysis is used to get information about the states of stress and strain anywhere in the critical section. Moreover, the comparison between experimental evidence and numerical simulation provides the strain to fracture for each test. The geometries of the specimens are studied, to reduce the number of different tests needed for an effective tuning of the model. Outcomes of this optimization are detailed in the paper. Tuning of material constitutive law, and of damage model, is achieved by means of inverse techniques, starting from global load-deflection experimental data. The damage model is implemented in a commercial FEM code as user subroutine. Eventually, the accuracy of the elasto-plastic description and damage prediction of the adopted formulation is investigated