报告题目：A Critical Review of Popular Failure Criteria for Composites
报告人：李曙光（University of Nottingham）
报告时间：2016年4月5日下午14：30
报告地点：航空宇航学院报告厅A18-529
主办单位：国际交流合作处、科协、航空宇航学院
报告人简介：
LI, Shuguang 李曙光, Professor of Aerospace Composites, is a part of the Institute for Aerospace Technology, Faculty of Engineering, University of Nottingham, UK. He was awarded BEng and MEng from NUAA in 1982 and 1984, respectively. His first academic career was at NUAA between 1984 and1988 as a lecturer. He then obtained his PhD from University of Manchester in 1993. He returned back to his academic track as a lecturer at the University of Manchester in 1995. He was appointed to his present position in 2012.
Professor Li was involved in the background for the 1st World Wide Failure Exercise (WWFE-I) for polymer composites (on 2D failure theories). He was on the advisory board of the 2nd Exercise of the same (WWFE-II, on 3D failure theories). He is one of the organisations of the 3rd, i.e. WWFE-III (on damage theories). The outcomes have been being published in Journal of Composite Materials.
Professor Li is on the editorial board of International Journal of Mechanical Sciences. He is a visiting professor of NUAA. He has published well over 100 academic papers, most of them in high impact international journals. His main research interest is in the area of analysis of composite materials and structures, in particular, on subjects of modelling damage and failure, micromechanics and material characterisation in recent years.
报告简介：
An appropriate failure criterion has always been a key part of structural design and analysis. For isotropic and ductile materials, such as metals, the von Mises failure criterion has been well-established, in fact, so established that users start to overlook its underlying assumptions. As the aerospace industry treads hastily into the composite era, demands on accurate and reliable failure criteria become more and more acute. Designers start to realise that it is not sustainable in order to support the ever demanding design practices based on the ‘make and test’ philosophy. However, an accurate and reliable criterion is unlike to arise from one’s intuition. Consistency with physical laws and logic assumptions and approximations are essential before experimental validations become relevant. Over the years, dozens of failure criteria, if not more, have been proposed by various researchers and practitioners. Many of them have been put forward in a casual manner without much mathematical and physical rigor. Those attempted to follow a rigorous route often found themselves in awkwardly sophisticated forms such that users were too occupied in interpreting and implementing these theories to contemplate the applicability of them. Blind use of failure criteria for composites has thus become the norm. The consequence is that the evaluation of a design has to be left to the experimental validation, back to a position not much far from the ‘make and test’ practices. In the lecture, failure criteria for composites commonly employed in engineering are subject to a critical review. The objectives are to highlight the basic assumptions and approximations of each criterion, to elaborate their implications and consequences, especially for those seemingly well-known but actually hardly justifiable without substantially undermining the applicability of the criterion, and to reveal generic relationships among relevant criteria wherever appropriate so that users would have an improved level confidence when selecting an appropriate one for their specific applications.
