BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Anomalous dynamics of snap-through instabilities - Michael Gomez (
 University of Cambridge)
DTSTART:20190117T130000Z
DTEND:20190117T140000Z
UID:TALK117334@talks.cam.ac.uk
CONTACT:Anne Herrmann
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 ju
 mp after being turned inside-out\, while snap-through is harnessed to gene
 rate fast motions in applications ranging from soft robotics to artificial
  heart valves. In biology\, snap-through has long been exploited to conver
 t energy stored slowly into explosive movements: both the leaf of the Venu
 s flytrap and the beak of the hummingbird snap-through to catch prey unawa
 res. Despite the ubiquity of snap-through in nature and engineering\, its 
 dynamics is usually only understood qualitatively\, with many examples rep
 orted of delay phenomena in which snap-through occurs much more slowly tha
 n would be expected for an elastic instability. To explain this discrepanc
 y\, it is commonly assumed that some dissipation mechanism (such as viscoe
 lasticity) must be causing the system to lose energy and slow down.\n\nIn 
 this talk we first demonstrate that anomalously slow dynamics are\, in fac
 t\, possible in elastic systems with little or no dissipation. This time d
 elay arises from the remnant or 'ghost' of the snap-through bifurcation\, 
 and is reminiscent of the 'critical slowing down' observed in other areas 
 of physics such as phase transitions. However\, in many real systems (incl
 uding the popper toy)\, viscoelastic effects are present to some degree. T
 o gain insight into the influence of viscoelasticity we then study a Mises
  truss as a simple model system that exhibits bistability and snap-through
 . Using a combination of asymptotic analysis and direct numerical solution
 s\, we elucidate the role that viscoelastic effects play in obtaining anom
 alously slow snap-through dynamics\, as opposed to the purely elastic slow
 ing down.
LOCATION:MR11\, Centre for Mathematical Sciences\, Wilberforce Road\, Camb
 ridge
END:VEVENT
END:VCALENDAR