题目：Mapping Strain and Stress Fields in Soft Materials
报告人：龙荣，加拿大阿尔伯塔大学，助理教授
时间： 7月9日下午4:00-5:00
地点： 力学一楼二楼239会议室
报告人简介：
Rong Longis an Assistant Professor in the Department of Mechanical Engineering at University of Alberta in Canada. Prior to that, he was a Research Associate at University of Colorado at Boulder in 2012 and a Postdoctoral Associate at Cornell University in 2011. He received his PhD degree in Theoretical and Applied Mechanics from Cornell University in 2011 and his Bachelor degree in the same field from University of Science and Technology of China in 2006. His research interests include: multi-physics and nonlinear mechanics of soft materials, fracture mechanics, cell mechanics and biomaterials, and contact mechanics and adhesion.
报告内容简介：
In this talk I will present our recent work to map the three dimensional (3D) strain and stress fields in soft materials based on fluorescent particle tracking. This is motivated by the great interest in measuring mechanical tractions exerted by biological cells on a 3D extracellular matrix (ECM). The mechanical tractions play essential roles in many cellular functions such as cell migration and cell adhesion. Conventional tools for quantifying cellular tractions require the cells to be placed on a two dimensional (2D) substrate. However, in vivo most animal cells reside in a 3D ECM, and they are found to exhibit different behaviors in comparison to their counterparts in 2D. Research on 3D traction measurement is still in its infancy. I will focus on three unique features of our technique: (i) a defocused particle tracking method to map the 3D displacements of fluorescent particles embedded in the sample material; (ii) a moving least square interpolation method to determine strain field from discrete displacement measurements; (iii) a method to determine stresses from strains for incompressible materials. We validated this new technique by mapping the strain and stress fields within the bulk of a soft polyacrylamide gel layer indented by a millimeter sized glass ball. Finally I will discuss our current efforts to apply this technique to study soft material fracture and the mechanics of adaptable polymers.
