报告题目：A study on spontaneous adiabatic shear band formation in Electro-Magnetically collapsing cylinders

报告人:                                  Prof. D. Rittel

Technion –Faculty of Mechanical Engineering,

Technion, Haifa, 32000, Israel

时间：2015年7月9日(周四)  16: 00     

地点：中国科学院力学研究所主楼344会议室

报告摘要：

The formation of shear bands in collapsing thick-walled cylinders (TWC) occurs in a spontaneous manner. The advantage of studyingspontaneous, as opposed to forced, shear localization, is that it highlights the inherent susceptibility of the material to adiabatic shear banding without prescribed geometrical constraints. In the case of spontaneous shear localization, the role of microstructure (grain size andgrain boundaries) on localization, is still unresolved. Using an electro-magnetic set-up, for the collapse of thick-walled cylinders, we examined the shear band formation and evolution in sevenmetallic alloys, witha wide range of strength and failure properties. To assess microstructural effects, we conducted systematic tests on copper and Ti6Al4Vwith different grain sizes. Our results match quite well previously reported data on much larger specimens, showing the absence of a size effect, on adiabatic shearing.However, the measured shear band spacing, in this study,do not match the predictions of existing analytical models, indicating that the physics of the problem needs to be better modeled. 

报告人简介：

D. Rittel holds a PhD in Materials Science (1988) from the Hebrew University of Jerusalem. He spent 2 years as a postdoc at Yale University working on the fracture of tungsten base heavy alloys, followed by 3.5 years at EcolePolytechnique (France), working on experimental dynamic fracture mechanics. He joined Technion (Mechanical Engineering) in 1994 where he founded the Dynamic Fracture Laboratory.

As of today, D. Rittel holds the Zandman Chair in Experimental Mechanics, heads the Materials Mechanics Center. He is also the Deputy Senior Vice President (Vice Provost) of Technion. D. Rittel was the Clark B. Millikan Visiting Professor in Aeronautics (2007) at Caltech and incumubent of a Catedra de Excellencia at UC3M (Madrid) in 2012. And recently he was awarded the prestigious 2015 AngiolaGili è CataldoAgostinelli international prize, by the Academy of Sciences of Torino (Italy) in the Applied and Theoretical Mechanics category. He has co-authored about 115 journal publications. Dr. Rittel is also Associate Editor of Experimental Mechanics, Mechanics of Materials and the International Journal of Engineering Science.

报告联系人：沈楠  (office@lnm.imech.ac.cn 82543935)