报告题目Cyclic Plasticity and Multiaxial Fatigue
报告人：Prof. Yanyao Jiang
时 间：2008年6月24日，星期二下午 2：00~3：30
地 点:第四教学楼102室
联系人：化工机械研究所叶笃毅教授，电话87951216
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报告内容简介
Plastic deformation is difficult to avoid in many design situations. Quite in contrast to the common sense of the engineers, it will be demonstrated with experiments that most of the mechanical components subjected to repeated loading experience cyclic elastic-plastic deformation. While cyclic plasticity may occur in localized areas in the machine and structural components, it should be noted that it is these areas where failures are initiated. Therefore, this presentation will begin with an introduction to the concepts and experimental phenomena of cyclic plasticity with a particular emphasis on the cyclic ratcheting phenomenon. A concentration will be placed on the theoretical modeling of the experimentally observed stress-strain behavior. Several theories will be presented and the characteristics of the models will be pointed out. A newly developed cyclic plasticity model will be discussed in detail.
A major result of cyclic plastic deformation is fatigue. Fatigue failure has been the most important concern in the design of aircraft and ground vehicles. In this presentation, an innovative fatigue damage model will be introduced. The model incorporates the critical plane concept in multiaxial fatigue, plastic strain energy, and material memory in cyclic plasticity. With an incremental form, the model does not require a cycle counting method for variable amplitude loading. The model is designed to consider mean stress and loading sequence effects. Features of the new model will be discussed. Verification of the model is made by comparing the predictions obtained by using the model and experimental data of several materials under different loading conditions.
Prof. Jiang 简介
Yanyao Jiang is Professor and Graduate Director in the Mechanical Engineering Department at the University of Nevada, Reno (UNR). He received his B.S. degree in Mechanical Engineering at the Northeast University in China in 1983, M.S. degree in Solid Mechanics from the Zhejiang University in 1986, and Ph.D. degree in the Department of Mechanical Engineering at the University of Illinois at Urbana-Champaign in 1993. Professor Jiang has made contributions in cyclic plasticity, fatigue and fracture, rolling contact, and durability of bolted joints with over 100 academic publications and 1,000 citations. His research work has led to an understanding of the relationship between cyclic plasticity and fatigue failure. He developed plasticity models that have been widely used in research and have been implemented into the finite element code and the fatigue life prediction software packages for engineering applications. Professor Jiang has done pioneering research on the inhomogeneous cyclic plastic deformation and ratcheting deformation. His approach for crack growth predictions bridges the crack initiation stage and the crack growth stage in fatigue research. He explored the foundamental mechanisms of self-loosening of bolted joints.
Professor Jiang is an ASME Fellow. He was the recipient of the US NSF CAREER award, the Ford University Research Program, the Alexander von Humboldt Foundation Fraunhofer Bessel Research Award, and the Joint Research Fund for Overseas Chinese Young Scholars from the National Natural Science Foundation of China. He is currently Associate Editor of the ASME Journal of Engineering Materials and Technology and a member of the Editorial Board for the International Journal of Plasticity and the International Journal of Fatigue.
