Research Highlights

Here, we present some highlights of our department’s research soon after they are published. An effort is made to write about the specific research in an easy-to-understand language to make it accessible to those who are not specialists on that particular topic. Specialists and those want to know more can click on the link to the publication to gain an in-depth knowledge about that work.

Mechanics of Elastic Ribbons by Ramsharan Rangarajan's and Team, posted August 31, 2020

Ramsharan Rangarajan

Ribbons are slender structures characterized by three disparate geometric dimensions— length 𝓁, width 𝑤 and thickness h. The pair of large aspect ratios 𝓁∕𝑤 and 𝑤∕dictate their rich buckling-dominated mechanical behavior. In many ways, a growing field of research on the mechanics of ribbons is exemplary of an evolving paradigm in engineering that considers buckling and related geometric nonlinearities as features to be exploited, rather than as modes of failure. Understanding the feature-rich behavior of thin elastic ribbons is in fact ripe with opportunities for fundamental studies exploring the nexus between geometry and mechanics, and for conceiving of engineering applications that exploit geometric nonlinearity as a functioning principle.

In a recent study, the research group of Dr Ramsharan Rangarajan critically examine modeling approaches for elastic ribbons using detailed measurements of complex three-dimensional deformations realized in experiments. Rather surprisingly, they find that simple and practically realizable ribbon deformations contradict assumptions underlying the most commonly used models. They go on to identify and validate a geometrically nonlinear theory over a useful range of loading conditions.

Through the study, the researchers demonstrate annular ribbons to be prototypical systems for studying the mechanics of elastic ribbons. Their experiments reveal that annular ribbons exhibit a tunable degree of nonlinearity, possess multiple stable equilibria, show bifurcation phenomena correlated with the number of zero crossings in the mean curvature, and provide evidence for the localization of energy, thus making annular ribbons interesting mechanical systems to study in their own right.

Reference:

A Kumar, P Handral, D Bhandari, A Karmakar, R Rangarajan
Journal of the Mechanics and Physics of Solids, 104070, 2020.