哈尔滨工业大学（深圳）学术讲座

演讲人Speaker：Shuguang Li   University of Nottingham

题目Title: A. The Hashin failure criterion critically appraised；

B. The Tsai-Wu failure criterion fully rationalised

时间Date：2025年11月21日  Time：9：00

地点Venue：H栋 613室

邀请人Host：郭江龙 副教授

腾讯会议同步在线：https://meeting.tencent.com/dm/dX41VrvkC2id

腾讯会议ID：969-926-910 

Report A: The Hashin criterion is one the most popular failure criteria for fibre reinforced composites.  The most significant feature of the criterion is the failure modes introduced and the assumption that failure is determined by the traction on the failure plane.  For this assumption, there has never been any justification provided in the literature, by Hashin himself or anybody else, except the available arguments made as a part of the Mohr criterion, where the concept of plane failure as opposed to point failure was first introduced based on this very assumption.  However, it will be demonstrated that Mohr’s arguments were applicable only to isotropic materials strictly.  On the other hand, multiple contradictions to the assumption in the context of composite failure will be shown through the lecture, supported by physical evidence, although a single contradiction should be logically sufficient to disprove the general applicability of the Hashin criterion.  In each case, failure is observed in a plane on which traction vanishes completely, to which the failure cannot be attributed.  The assumption of failure determined by the traction on the failure plane as the cornerstone of the Hashin criterion is therefore unfounded both theoretically and physically for anisotropic materials, which dismisses the validity of the Hashin criterion in turn, if logic prevails.

Report B:  The original Tsai-Wu failure criterion has left an interactive coefficient undetermined.  Attempts to fix this loose end have been made again and again over the past half a century without any convincing and conclusive outcome.  The failure function employed in the criterion is a quadratic function and the failure envelope in the space of direct stresses is therefore a quadric surface.  For such a surface, analytic geometry as a branch of mathematics offers complete understanding.  However, this useful and also crucial fact has been turned a blind eye to ever since.  An appropriate exploration of the quadric surface associated with this failure function, whilst enhancing the mathematical rigour of the subject, reveals some necessary relationships amongst coefficients in the failure function as intrinsic properties of the quadric surface.  As a result, the loose coefficient can be strictly and uniquely determined, completely rationally.  A complementary condition arising from the same consideration reveals yet another important relationship associated with the transverse shear strength.  The same argument can be further generalised to extend the coverage of the Tsai-Wu criterion to orthotropic materials, again, completely rationally, where there has been lack of reasonable and useful failure criterion for genuinely orthotropic materials whilst they are on the rise in practical engineering applications, such as 3D textile composites.  The lecture will offer a full account on the development on this front of the study of composite materials.

个人简介(About the speaker):

八十年代中从职，先执教于南航（今南京航空航天大学），1988年赴英，1993年于英国曼彻斯特大学获博士学位后，在同校从事博士后研究工作，于1995在曼大重返教职，任讲师，2002年晋升高级讲师，后于2009年任诺丁汉大学Reader，并于2012年晋聘诺大航空技术学院航空复合材料学教授，2025年起冠誉诺大荣退教授。

校外兼南航和西北工业大学客座教授，Journal of Reinforced Plastics and Composites副主编，International Journal of Mechanical Sciences期刊编委，中国航空研究院特聘专家，中航飞机强度研究所秦岭专家，斯坦福大学和Elsevier联合发布的全球前2%顶尖科学家之一（当年、终身）。长期从事复合材料力学研究，目前研究领域涉及“复合材料性能预测、多尺度分析（RVE、单胞）”、“复合材料损伤和失效”、“连续纤维复合材料3D打印”、“航空结构设计”等。已发表论文100余篇，大都于权威学术期刊，并著有《Representative volume elements and unit cells》（Elsevier）和《现代复合材料多尺度数值表征方法》（科学出版社）。曾为第二、三届世界纤维复合材料失效理论评估（World Wide Failure Exercise-III）的顾问、组织者之一。