A PROBABILISTIC APPROACH FOR MODELLING OF FRACTURE IN MAGNESIUM DIE-CASTINGS

Abstract

Quasi-static tensile tests with specimens cut from a generic cast component are performed to characterise the
mechanical behaviour of the high-pressure die cast magnesium alloy AM60. The experimental data is used
to establish a probabilistic methodology for finite element modelling of thin-walled die castings subjected to
quasi-static loading. The cast magnesium alloy AM60 is described using an elastic-plastic constitutive model
consisting of a high-exponent, isotropic yield criterion, the associated flow law and an isotropic hardening rule.
A novel probabilistic approach for modelling of fracture in thin-walled magnesium die-castings using finite
element analysis is developed. The Cockcroft-Latham criterion for ductile fracture is adopted with the fracture
parameter assumed to follow a modified weakest link Weibull distribution. Comparison between the experimental
and predicted behaviour of the cast magnesium tensile specimens gives very promising results.