The Department of Mechanical Engineering at the University of Michigan will welcome John Hutchinson, the first speaker in the Mechanical Engineering 150th Anniversary Distinguished Lecture Series.
Abbott and James Lawrence Research Professor of Engineering, Gordon McKay Professor of Applied Mechanics, Emeritus, Harvard University
Lecture: Shell Buckling – the old and the new
April 6, 2018
Lecture 4:00 p.m.
Reception to Follow
2121 Bonisteel Blvd.
220 Chrysler Center
Ann Arbor, MI
The elastic buckling of shell structures such as spherical shells subject to external pressure and cylindrical shells loaded in axial compression is highly sensitive to imperfections and highly catastrophic. The buckling load of such structures is strongly dependent on the level and shape of geometric imperfections. This is an old and enduring story in which faculty and graduate students at Stanford were actively involved five decades ago. At loads below the buckling loads, buckling can be triggered in a shell structure by extraneous loads or disturbances. The robustness, or precariousness, of a loaded shell to such disturbances depends on the magnitude of the buckling energy barrier: the difference between the energies of the shell/loading system in the buckled and unbuckled states. Energy barriers are not new in thermodynamical systems where thermal fluctuations can drive the systems from one state to another, but the role of the energy barrier in shell buckling has only recently been considered. Recent theoretical and experimental work illustrating the roles of both imperfection and energy barriers in the buckling of shells will be discussed together an examination of efforts underway in the US and Europe to modernize the design codes for shell buckling. The technique of probing a shell loaded below its buckling pressure to measure its energy barrier and to ascertain its buckling load will also be discussed.
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 Research Professor of Engineering. Hutchinson and his collaborators work on problems in solid mechanics concerned with engineering materials and structures. Buckling, structural stability, elasticity, plasticity, fracture and micromechanics are all relevant in their research. Examples of ongoing research activities are: (1) efforts to extend plasticity theory to small scales, (2) instabilities in soft materials and shell structures, (3) fracture mechanics of tough ductile alloys, and (4) the mechanics of thin films, coating and multilayers. Hutchinson is a Fellow of the ASME, a member of the National Academy of Engineering and the National Academy of Sciences, and a foreign member of the Royal Society of London. Publications can be downloaded at http://www.seasharvard.edu/hutchinson.