ESPCI web site
Chelsea Davis
Associate Professor
Department of Mechanical Engineering, Department of Materials Science and Engineering, University of Delaware
Utilizing Mechanophores to Quantify Stress in Elastomeric Cutting
Cutting or fracture initiated by contact with a sharp object is a concern in many industries. Most companies try to prevent fracture in their products. However, some companies, like medical equipment producers, purposefully induce fracture using tools like scalpels. Ideal versions of these tools enable cutting using the minimum amount of energy while also minimizing unnecessary damage to the surrounding area. No matter whether fracture is desired or unwanted, understanding the effects blade and material properties have on the fracture and stress responses of the material is critical to enable better design of products. Our research aims to describe fracture and stress fields inside elastomers due to cutting and the effect blade radius has on these properties. The methodology to accomplish this utilizes a Y-shaped cutting apparatus developed in the Davis Research Group to quantify fracture toughness. Mechanophores (molecular force probes) are then coupled with confocal microscopy to visualize stress in situ. Elastomeric materials are cut with blades of varying radii while the cutting force measures the fracture toughness of the elastomer. Within the steady state cutting regime, mechanophore activation ahead of the propagating crack tip describes the behavior of fracture induced by different radii blades. The magnitude and distribution of stress ahead of the crack tip will be discussed and compared for the various blades. Then, the fluorescent response of the activated mechanophore is mapped to calculated stress using finite element analysis, quantifying the stress distribution in the material during cutting. These results demonstrate the importance of understanding cutting mechanics while presenting a novel method to quantify the performance of these cutting tools against elastomers. Our new approach enables direct quantification of stress distribution within polymer matrix composites and 3D printed materials towards better characterizing complex stress states that develop during cutting.
Brief Biography
Dr. Chelsea Davis joined the faculty of the University of Delaware as an associate professor in the Departments of Mechanical Engineering and Materials Science and Engineering in 2023. Previously, she worked in the School of Materials Engineering at Purdue University as an assistant professor where she established the Polymer Interfacial Mechanics Lab which focuses on the development of micromechanical characterization tools to investigate the interfacial and surface properties of soft materials. Dr. Davis obtained a B.S. in Textile Engineering from North Carolina State University in 2005 and an M.S. and Ph.D. in Polymer Science and Engineering from the University of Massachusetts Amherst in 2007 and 2012, respectively, with Prof. Alfred Crosby. Dr. Davis was a Michelin Postdoctoral Research Fellow at the ESPCI in Paris (2012-2013) with Prof. Costantino Creton and Prof. Anke Lindner. She then worked as an NRC Postdoctoral Fellow in the Polymers and Complex Fluids Group at the National Institute of Standards and Technology (2013-2016). Dr. Davis’s work has been recognized through the NSF CAREER Award and the Adhesion Society Early Career Scientist Award.
Website : PolymerInterfacialMechanics.com