A COMPARATIVE ANALYSIS OF TWO APPROACHES TO NONLOCAL DUCTILE DAMAGE MODELING

A new nonlocal version of Gurson–Tvergaard–Needleman model is presented, which includes a new scheme of delocalization of constitutive relations. The delocalization scheme has the eff ect of trapping the damage, which makes it possible to increase the accuracy of modeling the processes of destruction and to avoid excessive diff usion of material damage. As an alternative approach, a nonlocal thermodynamically consistent model of damage accumulation developed earlier is considered. For both models, effi cient schemes of integrating constitutive relations are presented. Using the problem of the destruction of a strip with a hole as an example, the results obtained by both models are compared. Despite the fact that the models under consideration are based on fundamentally diff erent hypotheses, the predicted integral characteristics and distributions of plastic deformations coincide with high accuracy. The coincidence of the predictions by two diff erent models greatly complicates the choice of model hypotheses based on integral characteristics. It is established, however, that for the two models there is a signifi cant discrepancy in the predictions of the local evolution of the porosity of the material. Thus, in the presence of reliable experimental data on local material damage, this eff ect can be used as the basis for new protocols for selecting and calibrating models.
   
Author:  V. S. Klyuchantsev, A. V. Shutov
Keywords:  nonlocal damage mechanics, large deformations, Gurson–Tvergaard–Needleman model, fi nite element method
Page:  1634