Younho Cho was born in Seoul, South Korea and received his B.S and M.S in the mechanical engineering department, Yonsei University, Seoul South Korea in 1987 and 1989 respectively. With the background in Fatigue and Fractures for M.S, he earned his Ph.D under the tutelage of Prof. Joseph. L. Roes in the major of ultrasonic NDE in the engineering science and mechanics department, the Pennsylvania State University (Penn State Univ.), U.S in May, 1995 where he spent another year as a research associate professor. After working 8 years as a tenure-track and tenured associate professor at the school of automotive and mechanical engineering, Inje University, South Korea in between 1996 and 2004, he joined the school of mechanical engineering of Pusan National University (PNU), South Korea as a tenure-track faculty and is currently an associate professor leading the NDE group of PNU with the appointment of adjunct professor at the civil and environmental engineering department, Northwestern University, U.S. During the period, he was also appointed as a senior research associate professor at Penn State Univ. from 2003 to 2004.

Younho Cho directed the World Class University Program on Advanced NDE sponsored by the Korean Government from 2009 to 2011. He served as the technical secretariat of the NDE division of ASME PVP society between 2003 and 2005. He is also a chair of the NDE division of the Korean Pressure Vessels and Piping Society (KPVP). He is a senior board member of the Korean Society for Nondestructive Testing (KSNT) in charge of the society’s international affairs and also a board and life-time member of the Korean Society of Mechanical Engineers and the Korean Nuclear Society, respectively. He is the recipient of 2011 Northwestern Ashbach research award grant, U.S and was also awarded by KSNT, the Korean Ministry of Education, Science and Technology, the Korea Association of Science and Academic Societies for “The Best Research Contributor” 2010, “The 2010 Best Researcher in Basic Nuclear Technology” 2010 and “The Best NDT paper award” 2011, respectively. He has given keynote speeches in a number of international academic meetings including the International Conference of Japanese Reliability Society held in Kyoto Japan, 2004, the Ultrasonic Workshop of Japanese Society of Nondestructive Inspection (JSNDI), Tokyo 2008, the International Union of Theoretical and Applied Mechanics (IUTAM) Taipei, Taiwan, 2009, the International Conference of Reliability Engineering, China, 2010 and the Far East NDT meeting held in Hangjhou, China May 2011, respectively. He was also invited for technical presentations and tutorials by a number of overseas’ institutes including Kyoto University, Tohoku University in Japan, Tingshua Uniersity, Beijing Inistitute of Technology in China, University of Sevilla in Spain, Malaysia Atomic Research Institute in Malaysia, Northwestern University, Penn State University, Georgia Institute of Technology, University of Maryland, Oak Ridge National Lab. U.S, respectively. His research interest focuses on ultrasonic guided wave NDE and SHM (Structural Heath Management), tomography, nonlinear elastic wave analysis, elastic wave modeling. He has authored and coauthored over 200 refereed journal and proceedings articles.

Abstract

Model Based Guided Wave NDE; The Evolution of Guided Wave NDE from “Magic” to “Physically Based Engineering Tool”

Utility of those waves propagating over a distance named “Guided Waves” renders abundant technical advantages in a variety of NDE applications. In recent years, the field has rapidly grown up as one of the most noticeable subjects in the NDE community from not only academic but also practical standpoints with all those cases of promising technology transfer extensively underway. A number of commercialized inspection units and techniques are already available in the market. However, the principle of guided waves physics, which is crucial for proper usage and subsequent data analysis of the equipments has not been fully revealed to field NDE engineers, yet mainly for the purpose of simplifying the operation scheme.

A simplified operation manual is necessary to boom up the market but quite often not sufficient to conduct the mission adequately. Are the Math and the Physics no longer needed for NDE engineers? The math based knowledge on guided wave physics and advanced softwares are battling against the challenging task to turn the technique from magic to a reliable engineering tool. In the sense, the guided wave NDE technique now requires us more to establish a firm physical foundation of understanding its sophisticated features to enrich utility and correct the improper usage of field data while the instrumentation is rapidly upgrading with more advanced functions. In this talk, the speaker addresses the importance of physical understanding of the characteristics of guided wave NDE, focusing on how the guided wave models can enhance NDE performance and alleviate the chance for a false call. The sample problems include the guided wave modal analysis with dispersion curves and wave structures, the guided wave scattering models, the phased array guided wave long range inspection for pipes, the guided wave sparse array imaging and the nonlinear guided wave feature analysis for micro-damage detection.