Mechanical and Civil Engineering Seminar

Thursday March 2, 2017 11:00 AM
Speaker: Eric Johnsen , Mechanical Engineering , University of Michigan

"Bubble dynamics near and in soft materials"

Location: Gates-Thomas 135
Given the ubiquity of cavitation in naval applications, considerable research activities have been dedicated to understanding cavitation dynamics in water and their impact on neighboring hard objects, e.g., vibrations, structural damage, etc. However, this knowledge does not immediately translate to bubble dynamics in or near soft materials, a phenomenon central to a variety of medical (therapeutic ultrasound, traumatic brain injury) and naval (erosion-resistant elastomeric coatings) applications. The complex rheology of soft matter and the strong coupling between the bubble and its surroundings pose tremendous challenges for predicting soft matter response to cavitation, including potential damage, at these high rates. This presentation summarizes our efforts toward developing numerical models and methods for simulating bubble dynamics in soft materials and applying these techniques to understand basic mechanics underlying these problems. Our numerical investigations of canonical, single-bubble problems have shed light on the role of viscoelasticity on the bubble dynamics characteristics, e.g., oscillation damping/frequency and bubble morphology, as well as quantified stresses and temperatures experienced in the surrounding medium. Our findings further indicate that, besides shock waves and liquid jet impacts known to erode hard materials, additional mechanisms such as viscous and elastic stresses, as well as local heating, are likely to contribute to damaging soft matter. Whether cavitation-induced damage is intended or not, this knowledge is essential to planning safe and efficient ultrasound procedures, as well as improving the design of cavitation-resistant materials.
Series: Mechanical and Civil Engineering Seminar

Contact: Sonya Lincoln at 626-395-3385 lincolns@caltech.edu

Department of Mechanical and Civil Engineering