The macroscopic properties of materials and structures that we observe and exploit in engineering applications result from complex interactions between physics at multiple length and time scales: electronic, atomistic, defects, domains, etc. Multiscale modeling seeks to understand the interactions between these physics across scales. However, assessing such interactions can be challenging due to the complex nature of material properties and the prohibitive computational cost of integral calculations. This talk will focus on how to quantify the propagation of material uncertainties across multiple scales. To this end, we exploit the multiscale and hierarchical nature of material response and develop a framework to quantify the overall uncertainty of material response induced by the uncertainties at finer scales without the need for integral calculations. Specifically, we rigorously bound the uncertainty at each scale and then combine the partial uncertainties in a way that provides a rigorous bound on the overall or integral uncertainty. The bound provides a conservative estimate on the uncertainty. Importantly, this approach does not require integral calculations that are prohibitively expensive and is able to quantify the propagation of uncertainties through different paths across scales. Finally, the developed framework has been employed to investigate how material uncertainties in the single-crystal properties of magnesium affect the ballistic performance of armor structures.

Dr. Xingsheng Sun is a tenure-track Assistant Professor in the Department of Mechanical and Aerospace Engineering at the University of Kentucky (UK). Prior to joining UK, he was a Postdoctoral Scholar in Aerospace at California Institute of Technology from 2018 to 2021. His main research interest lies in long-term atomistic modeling and simulations, multiscale quantification of material uncertainties, mechanics of materials in extreme conditions, and application-driven materials by design. Dr. Sun holds a Ph.D. degree in Aerospace Engineering from Virginia Tech, a M.S. degree in Mechanical Engineering from Hunan University (China), and a B.S. degree in Mechanical Engineering from Dalian University of Technology (China).