Speaker: Dr Pierluigi Cesana
Senior Research Fellow
Department of Mathematics and Statistics
La Trobe University
Title: Smart membranes that do not wrinkle
Date and time: Friday, 27 January 2017, 4:00-5:00pm.
Location: Building 8 Level 9 Room 66 (AGR) RMIT City campus
Abstract: For liquid crystal elastomers in the thin film limit, an interplay of material and structural non-linearities is observed. These membranes can display fine-scale features both due to wrinkling that one expects in thin elastic membranes and oscillations of the local optical axis that one expects in elastic liquid crystals. In this talk we present an energy-optimization approach based on relaxation and Gamma-convergence to describe the effective energy density of thin membranes of liquid crystal elastomers by providing a detailed characterization of the fine-scale features. Mathematically, this is an intricate minimization problem with many non-linear and non-convex constraints (such as kinematics, geometrical confinement, optical anisotropy). Importantly, we show existence of a regime where one has shear strain but no shear stress and all the fine-scale features are in-plane with no wrinkling. This may act as a mechanism preventing formation of wrinkles in membranes under complex boundary conditions. Based on this feature, current work is being carried on on the design of programmable membranes and wrinkle-free inflatable reflectors with potential applications in satellites and space probes.
Bio: I graduated at SISSA, Italy in 2009 with a PhD in calculus of variations and elasticity theory. I worked as a postdoc in the US across Caltech and Los Alamos Nat Lab till 2013 before moving to the Mathematical Institute at Oxford and as of 2015 am based at La Trobe. In my research I have been adopting energy-minimization approaches in materials science with a special focus on elastic-liquid crystals (artificial lenses and muscles) and metallurgy (pattern formation and topological defects in Shape-Memory Alloys). More recently I have been adopting tools from probability theory to study self-organization and criticality in the microstructure of elastic crystals.