IACM Colloquium
Speaker:
Prof. Rohan Abeyaratne
Massachusetts Institute of Technology
Title:
On a Continuum Theory of Surface Growth: Kinetics, Mechanics and Stability
Abstract:
Continuum mechanical modeling of surface growth requires some non-standard considerations. In this talk I will focus on the role of the reference configuration in surface growth: its evolving nature and the characterization thereof. After discussing some general aspects of the theory, I will illustrate its application to three problems: (i) actin filaments growing on the surfaces of a chain of magnetic beads;
(ii) a dendritic actin network growing between two AFM cantilevers; and
(iii) the growth of a spherical shell-like actin network where growth occurs on the inner surface with each new layer of material pushing out the previously formed layers. The associated experiments were carried out by Brangbour et al., Parekh et al. and Noireaux et al. respectively.
In problem (ii) the elongation-rate is found to be loading history dependent and in particular there can be two (or more) steady state elongation-rates corresponding to the same force. Eventually growth stalls when the stress on the network reaches a critical value. In contrast in problem (iii), the build-up of stress at the inner surface slows down accretion, while the increase in strain energy at the outer surface promotes ablation, and eventually, the system reaches a point where accretion is balanced by ablation (“treadmilling”).
If time permits, I will touch on the stability of a pre-compressed half-space - Biot's problem in the presence of surface growth.
Parts of this work were carried out jointly with Tal Cohen (MIT), Eric Puntel (Un. di Udine), Prashant Purohit (Un. of Pennsylvania) and Giuseppe Tomassetti (Un. degli Studi Roma Tre).
Short Bio:
Rohan Abeyaratne is the Quentin Berg Professor of Mechanics at MIT. He is a Fellow of ASME and is the recipient of ASME’s 2010 Daniel Drucker Medal. He is also a Fellow of the American Academy of Mechanics where he served a two-year term as its President. Professor Abeyaratne is the recipient of a MacVicar Fellowship, MIT’s highest award for education.
Professor Abeyaratne’s research interest is in the field of theoretical mechanics and has included work on cavitation, phase transitions and surface growth. He has published extensively, including four books, the Evolution of Phase Transitions and the Mechanics of Elastic Solids:
Volume I: Mathematical Preliminaries; Volume II: Continuum Mechanics and Volume III: An Introduction to Finite Elasticity.
From 2009-2013 he was the CEO of the Singapore-MIT Alliance for Research and Technology (SMART), MIT's largest international program. Prior to this, Professor Abeyaratne was the Head of the Department of Mechanical Engineering at MIT from 2001-2008.
Professor Abeyaratne received his B.Sc. in Mechanical Engineering from the University of Ceylon (1975), and his M.Sc. (1976) as well as Ph.D
(1979) degrees from the California Institute of Technology.
Time, Date & Location:
15:00, Thursday, 23th of June, 2022 @ Seminar Room 1 (main building)
Zoom Info:
https://us06web.zoom.us/j/7761040361?pwd=dEs4TFZxck01Vk5PQWR1TUxKdndwUT09
Meeting ID: 776 104 0361
Passcode: 787479
Host:
Phoebus Rosakis