Michael Thompson: His Seminal Contributions to Nonlinear Dynamics – and Beyond

Abstract

In this meeting we are honouring the outstanding achievements of Michael Thompson, who over a period of four decades, has become a world leader in the development of modern concepts of nonlinear dynamics and the application of these concepts to modern problems. Michael came up to Clare College, Cambridge in 1955, where he studied mechanical sciences. He was a brilliant undergraduate. In Part I of the Mechanical Sciences Tripos he won the Rex Moir Prize. In Part II he won the Archibald Denny Prize. Both of these were the top prizes in Mechanical Sciences. After graduating in 1958, he was determined to pursue a research career. At that time, research in structural engineering in Cambridge was dominated strongly by the work of Lord Baker and his colleagues in the plastic behaviour of metal structures. There were though, a number of smaller research cells in the Engineering Department, developing independently from the plastic structures group. There was a developing group in soil mechanics, another in the dynamics and vibrations of structures, as well as others. I had come from Bristol to Cambridge in 1954, with structural stability interests in both teaching and research. In teaching I had developed a series of lectures on structural stability in Part II of the Mechanical Sciences Tripos, and this brought me into contact with Michael and other final year students. This led to Michael deciding, on graduating, that he would like to research into some of the most challenging stability problems of engineering structures. And so began the career of one of the most distinguished researchers, in our time, in nonlinear mechanics and its applications. In 1958, when Michael graduated, the leading thinkers in the field of structural stability were concerned with, what one might call, static elastic stability, and researchers concentrated on the extension of simple static stability principles to new and evolving structural forms. One of the most baffling problems, at that time, was our inability to predict accurately the uniform, external, elastic-buckling pressure of thin spherical shells. Michael began his researches with the study of very thin copper shells, which he formed by the electro-chemical deposition of a very thin spherical layer of copper on a solid internal sphere of paraffin wax. After deposition, the internal paraffin wax was melted slowly through a pin-hole in the copper shell, to yield probably the most perfect spherical shells ever produced for such research. The shells were great works of art. What became evident from these studies was that, well before the theoretical critical external pressure could be achieved, the spherical geometry of the sphere was becoming minutely distorted from its original spherical form. As external pressure increased, the shell reached a highly dynamic condition of