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Prof. Giles Hunt
| Speaker: |
Prof. Giles Hunt
(University of Bath)
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| Date: |
Wednesday September 20, 2006 |
| Title: |
Buckling
in space time
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Abstract
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Structural buckling is usually seen as an
instantaneous or near-instantaneous process, initiated at some critical
load and leading to a post-buckling shape that resembles at least to
some degree that of initial buckling. For slender columns and thin
plates this is certainly true. But other classical structural forms,
the cylindrical shell under axial compression for instance, are more of
a challenge to understand. The final buckled shape will have little in
common with the critical mode. For the cylinder, it gives a diamond
instead of a chequerboard pattern, axially localized instead of being
distributed along the length, and like many examples from structural
geology occurring in a serial (sequential or cellular) manner rather
than instantaneously.
The talk will focus on the reasons for these difficulties, and attempt
to explain them in descriptive rather than technical or mathematical
terms. The importance of the stability of the critical equilibrium
state itself will be discussed, together with the effects of
restabilization of an initially unstable equilibrium path. Classical
examples from structural engineering and structural geology will be
used as illustrations. The talk will end with a full discussion of the
buckling and post-buckling of cylindrical shells, where the allowable
modeshapes combine in a distinctive symmetry-breaking manner, to allow
evolution towards the final diamond shape and select the associated
circumferential wavenumber.
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