  The design and development of cutting-edge light materials for extreme
conditions including high-speed impact remains a continuing and significant
challenge in spite of steady advances. Magnesium (Mg) and its alloys have
gained much attention, due to their high strength-to-weight ratio and potential
of further improvements in material properties such as strength and ductility.
In this paper, we adopt a recently developed computational framework to
quantify the effects of material uncertainties on the ballistic performance of
Mg alloys. The framework is able to determine the largest deviation in the
performance measure resulting from a finite variation in the corresponding
material properties. It can also provide rigorous upper bounds on the
probability of failure using known information about uncertainties and the
system, and then conservative safety design and certification can be achieved.
We specifically focus on AZ31B Mg alloys, and assume that the material is
well-characterized by the Johnson-Cook constitutive and failure models, but the
model parameters are uncertain. We determine the ordering of uncertainty
contributions for model parameters and the corresponding behavior regimes where
those parameters play a crucial role. Finally, we show that how this ordering
provides insight on the improvement of ballistic performance and the
development of new material models for Mg alloys.
