题目：Engineering Solutions for Fatigue and Fracture Assessment and Representation in Steel Structures
报告人：钱旭东副教授
邀请人：陈志军 教授
时间：2016年9月20日（星期二），上午10：00-11：30
地点：西六楼三楼会议室
Abstract
Engineering assessments for the fatigue and fracture failure in large-scale steel structures face critical barriers both in assessing the crack driving forces for the welded connections (often with a complex topology) and in quantifying the fracture resistance in complicated loading conditions (frequently involving mixed-mode actions). This seminar presents: 1) a novel approach in deriving the crack driving force based purely on the load-deformation responses of the welded connections, which eliminates the need for a very detailed crack-front mesh often required in the conventional domain-integral procedures; 2) an experimental procedure in measuring the fracture resistance (J-R) curve over the complete mixed-mode I and II range; and 3) an experimental approach to measure the J-R curve for surface cracked specimens, instead of the conventional through-thickness fracture specimens. Built upon these fundamental developments, this seminar further illustrates a method to translate the material fracture resistance into the load-deformation representation of large-scale tubular joints, via addressing the transferability issue in the fracture mechanics research.
For engineering applications, this seminar covers: 1) failure (ductile tearing) assessment of tubular joints fabricated by high-strength steels, which reveals the un-conservatism in the generic failure assessment curves in BS7910 in assessing tubular connections; and 2) the development of a new set of welding details, i.e., the full-capacity tubular joint welds (also known as the welder-optimized CJP welds), focusing on the fatigue performance of tubular joints and the potential of root cracking.
About the speaker
Dr. QIAN Xudong is currently an Associate Professor in the Department of Civil and Environmental Engineering at the National University of Singapore (NUS). He received his Bachelor (1st Class Honors) and PhD in Civil Engineering from NUS in 2000 and 2005, respectively. Prior to joining NUS as a faculty member in 2007, he worked as a post-doctoral research associate in the Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign (UIUC). Prof Qian’s research interest focuses on experimental fracture mechanics, fracture and fatigue assessment for steel/offshore structures, welded tubular connections, steel-concrete-steel composite structures, brittle fracture assessment for Arctic applications, polymer composite materials for deep-water applications, structural resistance under extreme and impact loadings. He has published more than 100 papers, which include about 60 papers in highly ranked (SCI) international journals. Prof Qian has been serving as members in different Technical Committees for the International Ship and Offshore Structures Congress. He is currently also a member of the ASTM E-08 committee on fatigue and fracture.
报告人简介：钱旭东博士现为新加坡国立大学土木与环境工程系副教授(终身教职)。他分别于2000年、2005年在新加坡国立大学土木与环境工程系获得学士和博士学位，2006-2007年曾在美国伊利诺伊香槟分校从事博士后研究工作，随后加入新加坡国立大学土木与环境工程系。其研究兴趣包含：实验断裂力学，钢/海洋结构的疲劳、断裂性能，焊接管节点，钢-混组合结构，北极地区结构物脆性断裂性能评估，复合材料在深水结构中的应用，在极端碰撞作用下结构的承载能力评估等。他目前已在国际重要期刊和会议上发表上100篇学术论文，其中包括60多篇高影响力的SCI期刊论文。现为多个国际船舶与海洋结构技术委员会的成员，还担任ASTM E-08疲劳与断裂委员会委员。
