Peridynamic micromechanical prediction of nonlocal damage initiation and propagation in DP steels based on real microstructure

Dual phase steels are the complex heterogeneous materials that are widely used in various automobile industries. It is important to develop numerical methods to enhance the capability of the damage mechanism prediction. Dual phase steels consist of soft ferrite and hard martensite phases and the grain boundaries play the main role as the important location with possible occurrence of damage in these materials. In this study, a microstructure-based approach using representative volume elements is utilized to evaluate the damage initiation and propagation. The material is modeled at the microscopic scale using real microstructural SEM images. A two-dimensional model is developed and the damage mechanisms of dual phase steels are simulated using a bond based peridynamic microstructural model. According to the peridynamic simulation, no mesh refinement is necessary, as damage is inherently characterized by bond breakages and the obtained damage patterns are compared with experimental SEM images. Finally, a sensitivity analysis is conducted to understand the effect of peridynamic discretization, real microstructure, horizon size and interface behavior on the damage pattern of the proposed model under tension static loading. It is shown that the obtained damage initiation and propagation patterns are in good agreement with the experimental results.