学术报告预告-Advanced Optical Techniques for Strain Measurement

Advanced Optical Techniques for Strain Measurement: Potentials, Limitations and Discussions

   Lianxiang Yang, PhD, Professor

Director of Optical Laboratory, Dept. Mechanical Engineering, Oakland University, USA

Abstract

This presentation will give a review of advanced optical techniques for strain measurement from very small (microstrain level) to very large level (a few of percent). Strain measurement is an important topic in mechanical and civil engineering, as well as the automotive and aerospace industry. In recent years, numerical analysis methods, such as Finite Element Analysis (FEA), have been widely used in these industries to attain fast and safe design and manufacturing. This numerical analysis often requires a rigid strain measurement tool because experimental results can be used either as starting data to build a numerical model or as validation data to improve the model. In a word, modern manufacturing design starts and ends with strain measurement results. This talking will present state-of-the-arts advanced optical techniques for whole filed strain measurement. With the development of 3D-digital holography, sub-micro level 3D displacements u, v, w can simultaneously be measured by a single camera which enables a continuous and a dynamical loading (by using a high speed camera) conditions. Recently developed spatial phase shift digital shearography enables a direct strain measurement from microstrains to a middle level at a continuous and a dynamical loading conditions. Digital image correlation (DIC) has be widely accepted by industry as a strain measurement tool which is suited particularly well for measuring strains from middle to very large level. Recently, many new applications by DIC have been developed, such as stain measurement at high and low temperature conditions; strain measurement with a large forming, such as stamping strain; cluster approach based multi-camera DIC system for measuring strain with a large object side, Forming limit measurement, edge crack stain measurement, and the most latest approach for direct thickness strain measurement etc. All of these developments and applications will be presented and demonstrated by examples of strain measurement for different applications. At the end, their potentials and limitations will be described and future development trends will be discussed.

Bio

Dr. Lianxiang Yang is a professor and the director of the optical laboratory at Oakland University in USA. Prior to joining Oakland University, he was an R&D scientist at JDS-Uniphase, Canada, a senior engineer at Dantec-Ettemeyer AG (Currently called Dantec-Dynamics), Germany, and a senior research fellow at the University of Kassel, Germany. Professor Yang has multidisciplinary research experiences including optical metrology, photo mechanics, nondestructive testing, design validation and optimization and so on. Dr. Yang has published 5 books or book chapters in USA, England and Germany, authored or co-authored about 200 peer-reviewed journal and conference papers and applied 11 patents in USA, Canada and Germany. Professor Yang is Associate Editors or on editor boards for multi international Journals, such as, Optical Engineering (SCI Journal); Materials Evaluation (SCI Journal); Optics and Lasers in Engineering (SCI Journal); Chinese Journal of Mechanical Engineering-English version (SCI Journal), SAE International Journal of Materials and Manufacturing; Journal of Holography and Speckle etc. Dr. Yang was the Chair of Material Modeling and Testing Committee of the SAE international. He has been a Fellow of SPIE and a Changjiang Lecture Professor of Hefei University of Technology since 2008 and a distinguished professor from Beijing Info Sci & Tech Univ since 2012.

 时 间:2015年12月18日(周五) 上午10:00-11:30

地 点: 清华大学航院 蒙民伟科技大楼N412