New Insights into the Dynamic Impact Buckling of Thin-Walled Structures
Professor Singer Memorial Lecture
Felix Pawlowski Collegiate Professor of Aerospace Engineering, Professor of Mechanical Engineering, University of Michigan & Visiting Professor of Aeronautics, Imperial College, London
Faculty of Aerospace Engineering
Technion – Israel Institute of Technology
The late Professor Josef Singer is widely regarded as the father of experimental buckling of thin-walled structures. In collaboration with Caltech researchers, the late Chuck Babcock and Johann Arbocz (Emeritus at TU Delft), these three giants built a formidable reputation and a firm foundation on the subject and provided extensive experimental results and associated analysis that illuminated and highlighted the importance of geometrical and material imperfections, boundary conditions and the manner by which the load is introduced into the structure. To this day, the vast numbers of people whose lives were touched and influenced by these gentleman at the Technion, Caltech and TU Delft, are grateful for their example. I was fortunate to have had two of them work closely with me towards the latter part of my Ph.D. studies and I am forever indebted for their generosity, time and mentoring. In this talk, I will provide some important new insights into the dynamic buckling of structures, illustrated through some simple examples and will provide several instances of lessons from shell buckling that we can now use in the analysis, design and implementation of novel energy absorbing structures. The time-dependent progressive evolution of transverse displacements of an impacted slender column will be used to derive a dynamic bifurcation condition assuming that the column is initially straight and free of geometrical imperfections. A critical time, t*, will be introduced and defined as the smallest time interval, measured from the time of impact, that is necessary for a dynamic bifurcation in the column response. The analysis will be extended to impacted crooked columns, which results in a time-history associated with the evolution of the buckling response. The notion of a critical time associated with dynamic bifurcation buckling will be examined in light of experimental results and associated numerical solutions. Finally, results from dynamic shell buckling in the context of designing energy absorbing structures will be presented and discussed.
The talk will be given in English
Mon, 17-02-2014, 16:30 (Gathering at 16:00)Classroom, ground floor, library, Aerospace Eng.
Light refreshments will be served before the lecture