本期学术论坛由 The University of Texas at Dallas 的 Hongbing Lu 教授主讲
题目：Experimental Characterization of Selected Materials: SingleCrystals, Ultra-Low-K Dielectric Film, Porous Materials, and Composites
报告人：Prof. Hongbing Lu
时间：11月29日上午10：00-11：30
地点：机械楼南高厅
报告摘要：
Mechanicalcharacterization and modeling of a few selected materials are presented. Thesematerials include single crystals, ultra-low-k dielectric film, porousmaterials (foams and aerogels), and polymer matrix composites. For singlecrystals, nanoindentation on three crystallographic orientations of a FCCsingle crystal was conducted, while indent profiles and load-displacementcurves were captured and modeled using single crystal plasticity with theconsideration of frictional contact at the interface. The anisotropicstress-strain curves were obtained under uniaxial stress states along differentaxes. For an ultra-low-k dielectric film, a protective layer was deposited toavoid direct contact of a nanoindenter tip with the brittle film. Thenanoindentation response was modeled using an inverse method to determine themechanical properties. On porous materials, in-situ micro-computed tomographywas obtained while compression of a plastic foam was conducted. The materialpoint method was used to model the microstructural evolution, and thesimulations captured the three-stages of deformation in the foam. In additionto foam, a class of porous nanostructured materials, namely ductile aerogelswere prepared, characterized, and modeled to evaluate the energy absorption,and acoustic properties. These aerogels provide drastic properties derived fromhierarchical random porous nanostructures. On composites, the interfacial shearstrength of between graphite fiber and polymer matrix in a unidirectionalcomposite was investigated by push-in nanoindentation, and a method tointroduce aligned carbon nanotube to the interphase region is developed toenhance the interfacial shear strengths.
Dr.Hongbing Lu is Professor, Associate Department Head and Louis Beecherl Jr.,Chair of Mechanical Engineering in the Erik Jonsson School of Engineering and Computer Science at the University of Texas at Dallas. He received his Ph.D. in Aeronautics at Caltech in 1997, M.S. degree in Engineering Mechanics at Tsinghua University in1988, and B.S. degree in Solid Mechanics at Huazhong University of Science andTechnology in 1986. He was on the faculty in the Department of Mechanical andAerospace Engineering between 1996 and 2009. He has been working on mechanicsof time-dependent materials, including porous nanostructured materials, polymersand composites. His work has been funded by National Science Foundation, NASA, AirForce, Navy, Army, NIH, and industry. He is an Associate Technical Editor ofExperimental Mechanics. He is an ASME fellow, SEM Fellow (Society forExperimental Mechanics), and a Corresponding Member of the InternationalAcademy of Engineering (Russia).