Damage evolution and forming limit predictions of an A12024-T3 aluminium alloy

In this paper, a plastic damage evolution equation for A12024-T3 sheets is proposed based on the Continuum Damage Mechanics (CDM) and an experimental stress-strain relationship. The forming limit strains of aluminium sheets are predicted based on a modified M-K model which includes the effect of material damage. The theoretical results show that the conventional over-estimations of limit strains in the balanced biaxial state are reduced significantly by taking the material damage into consideration. The predicted Forming Limit Curves are in agreement with the experimental curves even without the assumption of an initial groove on the sheet metal surface.