时间：2019-06-06 10:00
地点：九里1号综合楼240
报告人：Qingda Yang
个人简介：
Dr. Qingda Yang is a full professor of the Department of Mechanical and Aerospace Engineering at the University of Miami (Coral Gables, FL). He obtained his B.S. (Engineering Mechanics, 1991) and M. S. (solid mechanics, 1994) from Zhejiang University, China, and a PhD (Mechanical Engineering, 2000) from University of Michigan at Ann Arbor. Prior to joining University of Miami, Dr. Yang worked for Rockwell Scientific Company (formerly known as Rockwell Science Center) as a solid mechanics scientist from 2000 to 2006.
Dr. Yang joined the faculty of the Department of Mechanical and Aerospace Engineering at the University of Miami in 2006. Dr. Yang’s recent research has focused mainly on developing multi-scale methodologies that can lead to realistic virtual testing and designing of complex heterogeneous materials and structures under general and/or extreme thermal-mechanical loading environments. His research has attracted funding from many federal agencies and industrial companies. Dr. Yang is an author/coauthor of more than 90 peer-reviewed journal publications, 4 book chapters, and 30 refereed conference proceedings. He is an editorial board member for the Journal of Applied Composite Materials and the journal of Multifunctional Composites.
讲座内容：
Advanced composites have been increasingly used as primary load-bearing structures or structural members. While they offer many excellent properties, significant concerns regarding their long term durability and safety remain. One particular unsolved challenge is to quantify the uncertainty associated with the service life. Typical composites exhibit complex, multiple damage events including multiple crack initiation events within and between plies/tows from pristine materials, through their coupled growth, involving multiple bifurcation, coalescence, and ply-jumping, to eventual failure. These damage events occur at different length scales but are usually nonlinearly coupled during their evolution. How to account for such complicated, multiscale failure process in a structural model is extremely challenging.
This study will present a multiscale simulation platform based on our newly developed A-FEM framework. The multiscale approach is based on a series of hierarchical modeling and homogenization at three important length scales. It starts from microscopic length scale with models including explicit representation of fibers and matrix. The validated cohesive and nonlinear properties at laminar scale are then used in sub-laminar models which focuses on the nonlinear interaction of ply cracking and interface delamination. Finally, it will be shown that, by applying the homogenized elastic properties, failure descriptions of various failure modes, coupled with necessary ply-level nonlinearity that are obtained from the three scales, high fidelity prediction of the multiple, arbitrary damage evolution processes in composite structures can be achieved.
