Constitutive model of die-cast light-alloy thin-walled parts considering geometric imperfection

Abstract

Replacing steel with aluminum and shifting from forging to casting have become important means of automotive lightweight. Large integrated die-cast parts are gaining popularity among original equipment manufacturers. Engineers often ignore the influence of geometric imperfection on mechanical properties when simulating strength of thin-walled parts, therefore causing a bias. To investigate the relation between geometric imperfections and mechanical properties of die-cast light alloy, quasi-static tensile tests are conducted on the specimens of JDA1b aluminum alloy and JDM1 magnesium alloy. The specimens exhibit varying geometric imperfection factors (from 0 to 90 %) achieved by introducing circular holes with different diameters. The results show that the strength and elongation of JDA1b and JDM1 alloys decrease significantly as the geometric defect factor increases. Even small holes can significantly affect tensile strength. A constitutive model that incorporates the stress limit value and geometric imperfection factors is proposed, which has higher accuracy than the J–C model. Experiments and simulations on a die-cast thin-walled part validated the idea and proposed constitutive model. These findings provide essential insights into the influence of structural holes on the mechanical properties of die-cast light-alloy materials. The proposed constitutive model offers high-precision computational support for simulating the mechanical performance of parts.