应航天学院国际应用力学中心刘子顺教授的邀请，加利福尼亚州立大学李妍博士将来我校学术交流并做报告。

时间：2017年12月29日（周五）上午10：00

地点：教一楼南第二会议室

报告题目：Microstructure-based Material Sensitive Design Framework

Dr. Yan Li

Assistant Professor

Department of Mechanical and Aerospace Engineering

California State University, Long Beach

Microstructure determines fracture toughness of materials through the activation of different fracture mechanisms. To tailor the fracture toughness through microstructure design, it is important to establish relations between microstructure and fracture toughness. To this end, systematic characterization of microstructures, explicit tracking of crack propagation process and realistic representation of deformation and fracture at different length scales are required. A cohesive finite element method (CFEM) based multiscale framework is proposed for analyzing the effect of microstructural heterogeneity, phase morphology, texture, constituent behavior and interfacial bonding strength on fracture toughness. The approach uses the J-integral to calculate the initiation/propagation fracture toughness, allowing explicit representation of realistic microstructures and fundamental fracture mechanisms.

Both brittle and ductile materials can be analyzed using this framework. For two phase Al₂O₃/TiB₂ ceramics, the propagation fracture toughness is improved through fine microstructure size scale, rounded reinforcement morphology and appropriately balanced interphase bonding strength and compliance. This method allows competition between material deformation and fracture as well as competition between transgranular and intergranular fracture to be quantified. The methodology developed in this thesis is potentially useful for both the selection of materials and tailoring of microstructure to improve fracture resistance.

Bio-sketch:

Dr. Yan Li joined the Department of Mechanical and Aerospace Engineering at California State University, Long Beach as an Assistant Professor in Fall 2014. She received her PhD degree in Mechanical Engineering from Georgia Institute of Technology in 2014. Dr. Li's primary research interests are in the area of mechanics of advanced materials, involving multiscale/multiphysics modelling, integrated computational/experimental approaches for next generation material design, and application of material science and solid mechanics in advanced manufacturing. Dr. Li has worked on research projects supported by the U.S. Army Research Laboratory, Sandia National Laboratories, NSF CCMD (Center for Computational Materials Design) and collaborated with industry partners including Boeing, Gulfstream and GE.