报告人：Weinong Chen (Reilly Professor of AAE and MSE, Purdue University)
Abstract：Materials have been widely used in impact applications. To efficiently utilize the full potentials of the materials, novel impact experimental methods have been in continuous development to understand the mechanical response and failure behavior of natural and engineered materials under impact loading conditions. In this presentation, the recent developments in dynamic experimental techniques in the Impact Science Laboratory at Purdue University are outlined. These include simultaneous dynamic compression/torsion loading by a Kolsky bar, dynamic tri-axial compression method, and the integration of high-speed X-ray imaging methods with the dynamic loading techniques. Kolsky bars have been used mostly under uniaxial stress conditions. There have been various efforts to extend the method to multiaxial loading conditions. The challenge in combining normal/shear loading is the synchronization between the normal and shear stress waves. We recently developed a mechanical approach to achieve this synchronization. Pressure-sensitive materials require experimental methods that are capable of varying pressures on the material during mechanical characterization. We modified a Kolsky compression bar into a dynamic tri-axial technique and applied this new method to study the dynamic behavior of a number of geomaterials under a variety of hydrostatic pressures. The failure processes under impact can be a critical aspect in the impact resistance of materials. It is desired to track the damage initiation and evolution in real time during the dynamic deformation of the specimens, which has not been possible except for a few transparent materials under high-speed imaging. Recently, we integrated the high-speed X-ray imaging capabilities present at the Advanced Photon Source beamline 32ID-B (Argonne National Laboratory) with the high-rate loading offered by the Kolsky compression/tension bars and light gas guns. High-speed X-ray images and X-ray diffraction can be obtained simultaneously. These methods have been applied in the study of a variety of materials.
Short Bio: Professor Weinong Chen received his BS (1982) and MS (1985) degrees from Beihang University and Ph.D. (1995) in Aeronautics from California Institute of Technology.He also holds an Honorary Doctorate of Science in Technology (2017) from Tampere University of Technology (Finland). He is currently Reilly Professor of Aeronautics, Astronautics and Materials Engineering, and Professor of Mechanical Engineering (by courtesy) at Purdue University, West Lafayette, Indiana, USA. His research interests are in dynamic experimental technique development and dynamic material characterization. The research results from his group have been published in a book and over 175 journal articles. He is a Fellow of American Society of Mechanical Engineers, a Fellow of Society for Experimental Mechanics, and an Associate Fellow of American Institute of Aeronautics and Astronautics.