STUDY ON CONSTITUTIVE MODEL AND FRACTURE CRITERION OF HIGH PRESSURE CAST ALUMINUM ALLOY

High pressure cast aluminum alloy is one of the most commonly used lightweight alloy materials to realize structural lightweight. Its constitutive relation and fracture criterion are key to structural safety design. To explore the constitutive model and fracture criterion of high-pressure casting aluminum alloy ZTHJ01 under quasi-static state, six experimental specimens of high-pressure casting aluminum alloy, including standard tensile, R5 notch tensile, central hole tensile, plane shear, butterfly shear and three-point bending, were designed and tested in combination with Digital Image Correction (DIC). According to the stress-strain curve, two different mixed hardening criteria are extrapolated, and the strain hardening characteristics of high-pressure cast aluminum alloy are accurately described. The finite element simulation model is proposed, and the relationship between fracture strain and stress triaxiality and Lode angle parameters under different stress states is obtained. The Modified Mohr-Coulomb (MMC) fracture criterion and Hosford-Coulomb (HC) fracture criterion parameters are constructed and calibrated. The effectiveness of the fracture model under different hardening criteria is verified by cupping test and finite element simulation. The results show that the MMC and HC fracture criteria under two different hardening criteria can better predict the fracture failure of high-pressure cast aluminum alloy, and the MMC fracture model under swift voce hardening criteria shows higher accuracy.