The Multiple States of Elastic Rings: Stability and Transitions by John HUTCHINSON

Many well-known examples exist of elastic structures displaying distinctly different states under load, most commonly when they buckle, and there is considerable interest to design materials and structures capable of switching from one deformation state to another for functional purposes. In the world of structures, efforts are underway to exploit multi-state configurations especially in the design of foldable or collapsible structures. In my seminar, I will discuss recent research on the stability of multiple-state structures and attempt to highlight some of the basic issues.  The specific focus of the lecture will be on elastic rings which have an array of unexpected and unusual equilibrium states.  At issue is the stability of the states and the transitions between them, as will be illustrated by a series of experiments.

John Hutchinson received his undergraduate education in engineering mechanics at Lehigh University and his graduate education in mechanical engineering at Harvard University. He joined the Harvard faculty in the School of Engineering and Applied Sciences in 1964 and is currently the Abbott and James Lawrence Professor of Engineering Emeritus. Hutchinson and his collaborators work on problems in solid mechanics concerned with engineering materials and structures. Buckling, structural stability, elasticity, plasticity, fracture, and micro-mechanics are all central in their research. Ongoing research activities are:

(1) development of a mechanics framework for assessing the durability of thermal barrier coatings for gas turbine engines,

(2) fracture mechanics of tough ductile alloys,

(3) the mechanics of thin films, coatings, and multilayers, and

(4) stability phenomena in plates, shells, and soft materials.

Further information and publications can be downloaded at  https://groups.seas.harvard.edu/hutchinson/