報告題目：Auxetic Behaviour of Re-entrant Cellular Structured and graphene Kirigami at Nanoscale
報告時間：2017年7月7日（周五）9:00
報告地點：北院經管學院MBA樓210室
報 告 人：秦慶華 教授
Abstract:
Some typical two-dimensional (2D) materials are active elements used in nano-electro-mechanical systems (NEMS) design, owing to their excellent in-plane physical properties on mechanical, electrical and thermal aspects. Considering a component with negative Poisson’s ratio used in NEMS, the adoption of kirigamis made of periodic re-entrant honeycomb structures at nanoscale would be a feasible method. The focus of this thesis work is to investigate the specific auxetic behaviour of this kind of structures from typical tailored 2D materials. By employing the numerical simulation method: molecular dynamics simulation, the auxetic behaviour of re-entrant cellular structured kirigami is discussed thoroughly and concretely.
Three main effects of a re-entrant cellular structured kirigami are discussed here. They are size effect, surface effect and matrix effect of 2D materials. The study begins with a demonstration that a kirigami with specific auxetic property obtained by adjusting the sizes of its honeycombs. Making use of molecular dynamics experiments, the size effect on auxetic behaviour of the kirigami is discussed. The results show that, in some cases, the auxetic difference between the microscopic structured kirigami and macroscopic structure kirigami is negligible, which means the results from macro-kirigami could be used to predict the auxetic behaviour of nano-kirigami. Surface effect of kirigami is also illustrated from two aspects. The one is to identify the difference of mechanical responses between pure kirigami and hydrogenated kirigami at some geometry and loading condition. And another is from the difference of mechanical responses between microstructure kirigami and continuum kirigami under the same loading condition and geometric configuration. Graphene is selected as the major 2D material in the study. As kirigami tailored from various 2D materials would exhibit different mechanical behaviour, graphene, single-layer hexagonal boron nitride (h-BN) and single-layer molybdenum disulphide (MoS2) are selected as representative 2D materials to investigate the influence of this effect, without loss of generality.
報告人簡介：
秦慶華教授，于1984年和1990年獲華中科技大學固體力學專業(yè)碩士和博士學位，1994年獲DAAD—王寬誠基金赴德國Stuttgart大學訪問研究。1995年-1997年到清華大學作博士后研究；1997和2002年分獲澳大利亞研究理事會Queen Elizabeth II 研究員和Professorial Fellow位置，2004年至今在澳大利亞國立大學工學院擔任教授、副院長（2011-2013）、研究中心材料加工制造組的帶頭人等職位。2000年被聘為華中科技大學客座教授；2002年被天津大學聘為長江學者特聘教授。在應用力學領域，已發(fā)表300多篇期刊論文，出版7部專著，獲得澳大利亞科學院頒發(fā)的J. G. Russell獎。
