A constitutive description for casting aluminum alloy A104 based on the analysis of cylindrical and spherical void models

Casting aluminum alloys is a kind of materials containing numerous voids. Assuming these voids are cylindrical or spherical, a representative volume element of the material is isolated and investigated. Through the analysis of the velocity and strain fields of the cylindrical and spherical void-cell models and making use of a nonclassical elastoplastic constitutive relation, the microscopic stress fields of the two kinds of void-cell models are obtained, and it is further transformed to macroscopic stress using the principle of energy coincidence. Combining the evolution of void growth with that of void nucleation, the void evolution rule is obtained. The obtained expression of macroscopic stress and the void evolution rule are embedded in a simple mechanical model, an elastoplastic constitutive description is developed, which can take into account the effect of void evolution and large deformation. The corresponding numerical algorithm and finite element procedure are developed and applied to the analysis of the elastoplastic response and the porosity of casting aluminum alloy A104. The computed results show satisfactory agreement with experiments.