关于举办University of Minnesota乐嘉梁学术讲座的通知
发布时间: 2017-12-21

题 目:准脆性断裂随机计算力学研究新进展/Recent Progress in Stochastic Computation of Quasibrittle Fracture

时 间:201712279001100

地 点:7号楼二楼报告厅

报告人:University of Minnesota, Associate professor, 乐嘉梁 (Jia-Liang Le

欢迎广大师生参加

                        土木与交通学院

                        20171221

报告人简介:

Dr. Jia-Liang Le is currently an associate professor of Civil, Environmental, and Geo- Engineering at the University of Minnesota. He earned his B. Eng. (First Class Honors) and M. Eng. from the National University of Singapore, and a Ph.D. in structural mechanics from Northwestern University. He is a registered professional engineer. His research interests include fracture mechanics, probabilisticmechanics, scaling, computational mechanics and structuralreliability. He received the Best Paper Award of the 48th U.S. Rock Mechanics/Geomechanics Symposium, the Young Investigator Award from the U.S. Army Research Office, and the 2017 EMI Leonardo da Vinci Award from the American Society of Civil Engineers. He is currently serving on the editorial boards of Journal of Engineering Mechanics ASCE, and Science China: Technological Sciences. He has authored one research monograph (Probabilistic Mechanics of Quasibrittle Structures published by Cambridge University Press) and over 50 journal papers.

报告摘要:

Failure and damage of quasibrittle structures are often accompanied by various localization phenomena, which give rise to spurious mesh dependence of finite element (FE) simulations. Though extensive efforts have been devoted to developing computational approaches for suppressing the mesh dependence issue, the existing efforts largely focused on deterministic analysis. In this talk, I will discuss the mesh dependence issue in stochastic computation of quasibrittle fracture. I will first present a new probabilistic crack band model, which is anchored by a probabilistic treatment of damage initiation, localization, and propagation. This model regularizes the energy dissipation of a single material element for the transition between damage initiation and localization. Meanwhile, the model also takes into account the random onset of damage localization inside the finite element for the case where the element size is larger than the crack band width. The random location of the localization band is related to the random material strength, whose statistics is described by a finite weakest-link model. The second part of the talk will discuss the extension of the model to dynamic loading. To this end, I will present a rate-dependent finite weakest-link model, which describes the combined rate and size effects on the strength distribution of material elements. This model is validated by a set of stochastic discrete element simulations of aluminum nitride as a model system.The present results demonstrate that the rate-dependent finite weakest-link model provides an analytical link between the discrete element simulation and continuum FE simulation, which leads to a promising multiscale stochastic computational framework for quasibrittle fracture.