講座題目：化學-力學：固體力學和化學交叉學科中的挑戰(zhàn)

                            Chemo-Mechanics: Challenges at the Intersection of Solid Mechanics and Chemistry

　　主 講 人：Robert M. McMeeking

         美國國家工程院院士，美國加州大學圣芭芭拉分校材料與機械工程系特聘教授，德國薩爾布呂萊布尼茨新材料研究所外籍研究員

  主 持 人：方岱寧院士

　　時   間：2018年8月31日 8:30

　　地   點：中關村校區(qū) 7號樓報告廳

　　主辦單位：研究生院,、先進結構技術研究院

　　報名方式：掃描下方二維碼

　【主講人簡介】

  Robert M. McMeeking,，加州大學圣芭芭拉分校材料與機械工程系特聘教授，美國國家工程院院士，德國薩爾布呂萊布尼茨新材料研究所外籍研究員。1972年在蘇格蘭格拉斯哥大學以一級榮譽獲得理科學士學位，并于1976年在布朗大學James R. Rice教授指導下獲得固體力學博士學位,。他在斯坦福大學任職2年，擔任代理助理教授,，隨后擔任伊利諾伊香檳分校理論與應用力學系助理教授和副教授,。1985年加入加州大學圣芭芭拉分校（UCSB）擔任材料與機械工程系教授,，并于1992-1995年以及1999-2003年擔任機械工程系主任。McMeeking發(fā)表了250多篇科學論文,，涉及塑性,，斷裂力學，計算方法,，冰川學,，堅韌陶瓷，復合材料,，材料加工,，粉末固結和??燒結，鐵電體,，微觀結構演變,，納米摩擦學，驅動結構,，結構爆炸和碎片保護,，水下爆炸沖擊流體結構相互作用，細胞及其細胞骨架的力學,，鋰離子電池和燃料電池,。 1998年，當選為美國機械工程學會會員,，并于2002年被科學信息研究所評為材料科學與工程領域的高度引用研究員,。2005年當選美國國家工程院院士，并于2006年和2013年兩次獲得洪堡高級科學家獎,，2007年獲得布朗大學布朗工程校友獎,。2014年當選為英國皇家學院院士和愛丁堡皇家學會會員，并獲得2014年工程科學學會William Prager獎章和美國機械工程師學會2014年Timoshenko獎章,。

    Robert M. McMeeking is Distinguished Professor of Mechanical Engineering at the University of California, Santa Barbara, and is an External Member of the Leibniz Institute for New Materials, Saarbruecken, Germany.  He earned a B.Sc. (with 1st Class Honours) at the University of Glasgow, Scotland in 1972, and in 1976 he completed his Ph.D. in solid mechanics at Brown University under the supervision of Professor James R. Rice.  He spent 2 years at Stanford University as Acting Assistant Professor, and then was appointed Assistant Professor, and subsequently Associate Professor, at the University of Illinois at Urbana-Champaign, in the Theoretical and Applied Mechanics Department.  McMeeking moved to the University of California, Santa Barbara (UCSB) in 1985 as Professor of Materials and of Mechanical Engineering.  He was Chair of the Department of Mechanical Engineering 1992-1995 and again during 1999-2003.  He has published over 250 scientific papers on such subjects as plasticity, fracture mechanics, computational methods, glaciology, tough ceramics, composite materials, materials processing, powder consolidation and sintering, ferroelectrics, microstructural evolution, nanotribology, actuating structures, blast and fragment protection of structures, fluid structure interactions arising from underwater blast waves, the mechanics of the cell and its cytoskeleton, lithium-ion batteries and fuel-cells.  In 1998 he was advanced to Fellow grade in the American Society of Mechanical Engineers and in 2002 was recognized by the Institute for Scientific Information as a Highly Cited Researcher in the fields of Materials Science and Engineering.  McMeeking was elected to the U.S. National Academy of Engineering in 2005, and held a Humboldt Award for Senior Scientists in 2006 and again in 2013.  He was given the Brown Engineering Alumni Medal by Brown University in 2007, and elected Fellow of the U.K. Royal Academy of Engineering in 2012.  In 2014 he was also elected Fellow of the Royal Society of Edinburgh and received both the 2014 William Prager Medal of the Society of Engineering Science and the 2014 Timoshenko Medal of the American Society of Mechanical Engineers.  McMeeking was Editor of the Journal of Applied Mechanics for the term 2002-2012. 

【講座摘要】

      化學-力學是一個古老的工程學科,，至少可以追溯到唐代中國火藥的發(fā)明。蒸汽機和內燃機的出現(xiàn)更增加了該主題的工程重要性,，當然,，材料的機械性質從根本上來說也是它們的化學問題。但隨著相關領域的進一步發(fā)展,，又出現(xiàn)了許多新的問題,，且在這些問題中固體力學和化學的交叉起著至關重要的作用。因而,，必須要將固體力學與化學相關的重要性引入到研究問題中。要做到這一點,，必須考慮系統(tǒng)的能量構成,，以及不同類型的能量在熱力學中可以發(fā)揮的相對重要的作用,。例如，汽油的比能量遠大于通常與材料的彈性變形相關的應變能密度,。因此,，固體力學和化學發(fā)揮同等重要作用的主題有些特殊，人們必須將注意力集中在這些特殊領域,，以應對固體力學與化學交叉的挑戰(zhàn),。本次報告將討論從各種相關領域抽取出的化學-力學交叉問題。一個問題是在氧化環(huán)境中的中間溫度下SiC/SiC復合材料的應力破裂問題,，這是一系列內部化學和熱機械過程導致過早的局部纖維斷裂的結果,。通過建立的模型首次解釋了為什么這種失效機理在中等溫度下普遍存在而在低溫和高溫下不存在。固體力學在化學中發(fā)揮重要作用的另一個主題是鋰離子電池,，其中力學作用會影響離子傳輸,、氧化還原反應等電化學過程的速率。在生物細胞力學中,，同樣存在許多應力和力影響細胞生物化學,，細胞信號傳導和細胞對環(huán)境響應行為的現(xiàn)象。此外,，在凝膠和彈性體中,，化學和固體力學之間的相互作用會影響材料的狀態(tài)及其力學性質。

   Chemo-Mechanics is an old subject in engineering, dating back at least as far as the invention of gunpowder in China during the Tang dynasty.  Steam and internal combustion engines increased the engineering importance of the subject, and, of course, the nature of the mechanical properties of materials is fundamentally an issue of their chemistry.  But the area has grown, and today there are a large number of additional topics where the intersection of solid mechanics and chemistry is of importance.  Nevertheless, the importance of solid mechanics in relation to chemistry must be put in context.  To do this, one must consider the energy content of systems, and the relative importance of the roles that different types of energy can play in thermodynamics.  For example, the specific energy content of gasoline is vastly greater than the strain energy density typically associated with elastic deformation of materials.  Therefore, the topics in which both solid mechanics and chemistry play equally important roles are somewhat special, and one has to focus one’s attention on these special areas to address the challenges that lie at the intersection of solid mechanics and chemistry.

 This talk will address a few such areas drawn from a variety of subjects.  One area is stress rupture of SiC/SiC composites at intermediate temperatures in oxidizing environments, which is the result of a series of internal chemical and thermomechanical processes that lead to premature, localized fiber fracture.  The model developed has, for the first time, explained why this failure mechanism is prevalent at intermediate temperatures but not at low and high temperatures.  Another topic where solid mechanics plays a significant role in the chemistry is the subject of lithium-ion batteries, where mechanical work can bias the rates of electro-chemical processes that are involved in ion transport and redox reactions.  In biological cell mechanics there are many phenomena where mechanical stress and forces affect the cell biochemistry, cell signaling and cell behavior in response to its environment.  Additionally, in gels and elastomers interactions between chemistry and solid mechanics influence the state of the material and its mechanical properties.