報告會簡介
報告人：Lin Ye教授
時間：2018年4月11日（星期三）9：30
地點：友誼校區國際交流中心國一會議室
題目：“Liquid Armour” – How Much Energy It Can Absorb?
沖擊動力學講壇簡介
沖擊動力學講壇由西北工業大學沖擊動力學及其工程應用國際聯合研究中心建立的一個學術交流平臺。西北工業大學沖擊動力學及其工程應用國際聯合研究中心由西工大與荷蘭代爾夫特理工大學、法國巴黎第六大學、澳大利亞悉尼大學、美國阿克倫大學和澳大利亞斯威本科技大學等國際知名高校共同建立，2017年獲國家國際科技合作基地認定。中心圍繞航空航天重大力學問題以及“大飛機”和“兩機專項”等重大科技專項的工程需求，致力于先進結構與材料的動態響應、破壞機理等重大科學問題及工程化應用研究，與國際伙伴合作形成了一批具有國內領先和國際先進水平的聯合成果，解決了飛行器結構及航空發動機抗離散源撞擊等國際性難題，相關成果已在ARJ21、C919、蛟龍AG600等國家重點型號飛機抗沖擊設計中得到應用。
沖擊動力學講壇面向全校師生，不定期邀請沖擊動力學領域的國際著名學者，以邀請報告或學術沙龍的形式分享科研成果和進展、研究經驗和心得，提升我校師生尤其是青年教師在沖擊動力學、航空宇航等學科領域的基礎性和前沿性，同時促進西北工業大學國際合作交流工作的發展。
內容簡介
Shear thickening fluids (STFs), are concentrated colloidal suspensions composed of non-aggregating solid particles suspended in fluids. These suspensions have the property of an abrupt increase in the fluid viscosity when the shear rate reaches its critical value.One promising application of STFs is to develop passive, energy-absorbing systems, in which STFs can divert or dissipate the energy via viscosity, friction or “plasticity” depending on deformation modes and rates. It was reported the Kevlar fabrics impregnated with a STF enhance ballistic penetration resistance, frequently referred to as“liquid armor”,thus offering flexible body armour with significantly reduced thickness, though the conflicting results were also reported.
This work established some methods and approaches to investigate and characterizetheenergy-absorbing/dissipation properties of a STFsystematically after the shear-thickening transition. The STF selected for this work is composed of 58 vol.% dispersion of styrene/acrylate particles in ethylene glycol. The lap-shear and double-cantilever-beam specimens with the STF as adhesive layer were adopted to characterize shear strength, braking energy and mode-I fracture energy of the STF at different shear or crack opening displacement rates. The load-displacement curve as well as the high-speed video recording confirmed that the STF showed a “solid” behaviour at high rates by developing a brittle shear failure or stable crack extension that corresponds to a brittle fracture behaviour. The results indicated that the shear rate has a significant effect on the lap shear strength (with a plateau value of 0.3 MPa) and the total braking energy (with an average value of 4 kJ/m2) of the STF, while the displacement rate and the STF thickness have a significant effect on the mode-I fracture energy of the STF. The fracture energy increases as an increase in the displacement rate, while a plateau value of 240 J/m2was observed at high rates. Moreover, the studies were conducted to quantitatively characterize the energy absorption capacity of the STF under penetration impact and pull-out fracture at different impact or pull-out speeds. The results confirmed that the penetration rate again has a significant effect on energy absorbing capacity of the STF. In comparison with the energy absorbing behaviour of some cellular materials in literature, the STF outperforms a polyurethane foam in terms of penetration energy absorbing capacity.
報告人簡介
Lin Ye教授為澳大利亞悉尼大學航空航天、機械和機電工程學院教授，悉尼大學先進材料技術中心主任。他于1982年在哈爾濱工程大學獲得學士學位，1984年和1987年在北京航空航天大學分別獲得碩士和博士學位，1988年加入西安交通大學擔任講師，1990-1992年間，在德國TUKInstitute for Composite Materials (IVW GmbH)實驗室擔任Alexander von Humboldt研究員。1992年7月加入悉尼大學，主要研究復合材料科學與技術、智能材料與結構、納米材料和納米復合材料、結構完整性和耐久性。Lin Ye教授于2005年當選為澳大利亞技術和工程學院（Australian Academy of Technology and engineering, ATSE）院士。目前擔任Composites Communications副主編、CompositesScienceand Technology等一系列國際雜志編委。編著或參編13部書,發表SCI論文249篇和102篇會議文章。
