Skip to main content

research

A design principle for actuation of nematic glass sheets

Submitted by Amit Acharya on

(in Journal of Elasticity)

A continuum mechanical framework is developed for determining a) the class of stress-free deformed shapes and corresponding director distributions on the undeformed configuration of a nematic glass membrane that has a prescribed spontaneous stretch field and b) the class of undeformed configurations and corresponding director distributions on it resulting in a stress-free given deformed shape of a nematic glass sheet with a prescribed spontaneous stretch field. The proposed solution rests on an understanding of how the Lagrangian dyad of a deformation of a membrane maps into the Euleriandyad in three dimensional ambient space. Interesting connections between these practical questions of design and the mathematical theory of isometric embeddings of manifolds, deformations between two prescribed Riemannian manifolds, and the slip-line theory of plasticity are pointed out.

Strain Localization in Dry Sheared Fault Gouge: A Compactivity based approach

Submitted by Ahmed Elbanna on

Abstract: Shear banding is widely observed in natural fault zones as well as in laboratory experiments on granular materials. Understanding the dynamics of strain localization under different loading conditions is essential for quantifying strength evolution of fault gouge and energy partitioning during earthquakes and characterizing rheological transitions and fault zone structure changes. To that end, we develop a physics-based continuum model for strain localization in sheared granular materials.

Mechanics and Mussel adhesion: How bulk porosity may help things stick better

Submitted by Ahmed Elbanna on

On the Role of the Plaque Porous Structure in Mussel Adhesion: Implications for Adhesion Control Using Bulk Patterning

Ahmed Ghareeb and Ahmed Elbanna -- Journal of Applied Mechanics (2018)