Nov 2023
Abstract
The high-speed measurement of stress fields within fluids and soft materials is a pivotal aspect of research with significant implications across various industries, including plastic molding and healthcare advancements. These advancements range from innovative needle-free injections to accurate predictions of blood vessel ruptures. This seminar will delve into two cutting-edge optical measurement methods: the Background Oriented Schlieren (BOS) technique and photoelastic stress measurement.
The BOS technique offers a more intuitive visualization and quantification of density gradients and pressure fields, outperforming other existing methods. Its effectiveness has been corroborated through the study of laser-induced underwater shockwaves, demonstrating consistency with hydrophone data. The talk will also share best practices for achieving optimal results with BOS measurements.
Photoelastic measurement, traditionally applied to hard materials like glass, has been successfully adapted to evaluate stresses in softer substances. Utilizing high-speed polarization cameras, this technique correlates the polarization of light with the stress distribution within a material. Our findings reveal its potential in assessing materials with lower rigidity than glass, such as gelatin gels. The incorporation of vector tomography has enabled precise 3D stress field reconstructions. The seminar will conclude by exploring the future directions and applications of these optical stress measurement techniques.
Bio
Dr. Yoshiyuki Tagawa, Full Professor at the Department of Mechanical Systems Engineering, Graduate School of Tokyo University of Agriculture and Technology.
Completed his doctorate at the Graduate School of Engineering, University of Tokyo in 2009. Doctor of Engineering. After serving as a Japan Society for the Promotion of Science (JSPS) Postdoctoral Fellow and a postdoctoral researcher at the University of Twente in the Netherlands, he joined Tokyo University of Agriculture and Technology as an Associate Professor in 2013, and has held his current position since 2020. Engaged in the development of new medical engineering technologies based on fluid engineering and research on high-viscosity & supersonic microjets. His work has been consistently funded by prestigious grants from the Japan Society for the Promotion of Science and other significant sources. Recipient of numerous awards, including the Minister of Education, Culture, Sports, Science and Technology Award in the field of science and technology in fiscal year 2021, the Andrea Prosperetti Award. He is an advisory board member of the International Journal of Multiphase Flow, associate member of the Science Council of Japan, director of the Japan Society of Multiphase Flow, among others.