Meso-mechanics and damage evolution of AA5182-O aluminum alloy sheet Based on the GTN model

Abstract

According to meso-damage mechanics, the evolution of the volume of micro-voids is an important factor that contributes to damage and fracture. Improving the prediction accuracy of plastic deformation of aluminum alloy sheet is an important endeavor for studying the influence of various factors on plastic meso-damage evolution. Based on the GTN (Gurson-Tvergaard-Needleman) model, the meso-mechanics and damage evolution of AA5182-O rolled aluminum alloy sheet were studied in this paper. The mechanical properties were obtained through uniaxial tensile tests for studying the effect of the strain rate and sampling direction on each GTN damage parameter. Using the response surface method, the GTN model of each strain rate specimen at R00° was calibrated by the finite element method, and the influence of each damage parameter on the stress–strain and void volume evolution curves are studied. The results show that the strain rate has no effect on the initial void volume fraction and critical void volume fraction but has a significant effect on nucleation void volume fraction and fracture void volume fraction. An increase in the initial void volume fraction will cause the fracture point of the material stress–strain curve to occur earlier but has no obvious effect on the slope of the void volume evolution. As the void nucleation volume fraction increases, the highest point of the true stress–strain curve will decrease, the fracture point will advance, and the slope of the curve will increase in the uniform deformation stage of the void volume evolution. However, increasing the critical void volume fraction and fracture void volume fraction will delay the fracture point of the stress–strain curve.