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SUMMARY:Elastic snap-through: from the Venus flytrap to jumping popper toy
 s - Michael Gomez
DTSTART:20190224T144000Z
DTEND:20190224T151500Z
UID:TALK120790@talks.cam.ac.uk
CONTACT:73969
DESCRIPTION:Snap-through buckling is a type of instability in which an ela
 stic object rapidly jumps from one state to another. Such instabilities ar
 e familiar from everyday life: children’s popper toys rapidly ‘pop’ 
 and jump after being turned inside-out\, while snap-through is harnessed t
 o generate fast motions in applications ranging from soft robotics to arti
 ficial heart valves. In biology\, snap-through has long been exploited to 
 convert energy stored slowly into explosive movements: both the leaf of th
 e Venus flytrap and the beak of the hummingbird snap-through to catch prey
  unawares. Despite the ubiquity of snap-through in nature and engineering\
 , its dynamics is usually only understood qualitatively\, with many exampl
 es reported of delay phenomena in which snap-through occurs much more slow
 ly than would be expected for an elastic instability. To explain this disc
 repancy\, it is commonly assumed that some dissipation mechanism (such as 
 material viscoelasticity) must be causing the system to lose energy and sl
 ow down. In this talk we examine how viscoelasticity influences the snap-t
 hrough dynamics of a simple truss-like structure. We present a regime diag
 ram that characterises when the timescale of snap-through is governed by v
 iscous or elastic effects\, and relate this to the creep behaviour we see 
 in jumping popper toys. 
LOCATION:Winstanley Lecture Theatre\, Trinity College
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