Experimental and numerical analysis of micromechanical damage for DP600 steel in fine-blanking process

In fine-blanking process, metallographic inspection shows that highly elongated and densely packed grains extend along the shear direction within a narrow large deformation region, meanwhile micro-cracks initiate and grow up. By taking the effect of shear loading into account, the recent modified GTN model proposed in 2014 is implemented and validated. The shear damage model combines the damage mechanics concept with the porous plasticity model and is applied to simulate fine-blanking process to verify its accuracy in predicting material damage and tearing fracture. The formation and propagation of shear band in fine-blanking process are studied. Both numerical results and experimental observations reveals that the effect of shear damage plays a significant role in inducing tearing, which eventually leads to fracture failure in the fine-blanking process.