A sand surface element for efficient modeling of residual stress in castings

This article describes a method to efficiently predict residual stresses in foundry castings. We replace explicit modeling of the sand mold during stress analysis by using a locally applied boundary condition element. Methods are given for assigning appropriate values to the individual elements, and we present several example problems. In these test problems, we also evaluate several constitutive models for the sand. We find that plastic strains and displacements in the casting do not depend strongly on the sand constitutive model. Further, the stress states produced, when using the new surface elements, are generally in good agreement with those found using a full mold. The computational advantages of the new element are demonstrated.