Papers »

Microvoid elongation and dilation based finite strain continuum damage model for ductile fracture

Damage in a metals occurs when there is an irreversible microstructural change that is detrimental to its mechanical properties. From a damage mechanics perspective, the local deterioration in mechanical properties due to ductile fracture in metals initiates with the nucleation of microvoids. This deterioration escalates during the void growth phase and ultimately reaches a maximum in the microvoid coalescence phase. The propensity of a microvoid to dilate or elongate during the void growth phase is governed by the state of stress, which in general defined by two variables: stress triaxiality and Lode parameter.

This study presents the formulation, implementation, calibration and validation of microvoid elongation and dilation based finite strain continuum damage model (MED-CDM). In this model, the damage evolution is derived from micromechanical analyses that can account for the microscopic damage due to microvoid elongation and dilation. The proposed model is implemented in Abaqus finite element program as a user-defined constitutive model. This model is calibrated and validated using existing experimental data. The proposed model is shown to accurately predict the load displacement behavior, fracture strains, fracture initiation locations and the underlying microscopic damage mechanisms that are responsible for the fracture initiation in ASTM A992 structural steels.

Author(s):

Ravi Kiran    
University of Notre Dame
United States

Kapil Khandelwal    
University of Notre Dame
United States