The Center for Predictive Integrated Structural Materials Science (PRISMS Center) is creating a unique framework for accelerated predictive materials science and rapid insertion of the latest scientific knowledge into next-generation ICME tools. There are three key elements of this framework. The first is a suite of high-performance, open-source integrated multi-scale computational tools for predicting microstructural evolution and mechanical behavior of structural metals. Specific modules include statistical mechanics, phase field, crystal plasticity simulation and real-space DFT codes. The second is the Materials Commons, a collaboration platform and information repository for the materials community. The third element of the PRISMS framework is a set of integrated scientific ''Use Cases'' in which these computational methods are linked with experiments to demonstrate the ability for improving our predictive understanding of magnesium alloys, in particular, the influence of microstructure on monotonic and cyclic mechanical behavior. This paper reviews progress toward these goals and future plans.

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In this paper, we study fatigue failure using the variational multiscale method (VMM). In the VMM, displacement jumps are represented using finite elements with specially constructed discontinuous shape functions. These elements are progressively added along the crack path during fatigue failure. The stiffness of these elements changes non-linearly in response to the accumulation of damage during cyclic loading. The evolution law for stiffness is represented as a function of traction and the number of loading cycles since the initial onset of failure. Numerical examples illustrate the use of this new methodology for modeling macroscopic crack growth under mode I loading as well as microscopic crack growth under mixed mode loading within the elastic regime. We find that the discontinuous elements can consistently predict the mode I stress intensity factor (SIF) and the micro-structurally short crack growth paths, and that the computed Paris law for steady crack growth is controlled primarily by two parameters in the decohesion law.

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We develop a finite element methodology to characterize the effects of silicone coating on Shape Memory Alloy (SMA) actuators during continuous actuation cycles. Slow cooling rates of thermally actuated SMA actuators have long been a hurdle for their widespread adoption. The use of a thermally conductive silicone coating provides a potential solution that improves cooling rates without much impact on the actuator thermal performance under single actuation. However, the effects of the coating on the thermal performance under cyclic actuation is unexplored. To verify the finite element model results, various thicknesses between 0.2 mm to 2.5 mm of the coating material were applied to 0.5 mm diameter SMA wires using a specially fabricated coating machine. The results of finite element models were first compared with and calibrated against experimentally measured thermal performance for single actuation cycle. Next, the actuation responses of the numerical models of these coated SMA wires are determined for multiple actuation cycles.