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SUMMARY:Damping from fragmented materials - Dr Jem Rongong\, Dept of Mecha
 nical Engineering\, University of Sheffield
DTSTART:20240301T160000Z
DTEND:20240301T170000Z
UID:TALK207142@talks.cam.ac.uk
CONTACT:46601
DESCRIPTION:\nVibration control is important in the design of light\, effi
 cient and environmentally acceptable machines and structures. While polyme
 rs are widely used as the energy dissipating element in damper designs\, t
 hey are often unsuitable for the operating environment that might include 
 extreme temperature\, pressure and radiation.\n\nFragmented material dampe
 rs (FMDs) involve many small fragments that can move a small distance rela
 tive to each other under dynamic loading\, but are held together by a fram
 e\, substrate or enclosure. Energy is dissipated via sliding friction at t
 he numerous contact points. FMDs offer vibration control over broad temper
 ature and frequency ranges and can be made from materials that survive in 
 harsh environments. Because energy dissipation comes from sliding friction
 \, FMD performance is sensitive to the static and dynamic strain applied. 
 Increasing dynamic strain activates the damper: the loss factor increases 
 while the stiffness drops. Higher static strain however\, reduces the leve
 l of activation and therefore increases stiffness.\n\nThis talk considers 
 the performance of several FMDs including tangled metal wire\, thermally s
 prayed ceramic and granular dampers. This includes consideration of materi
 al characterisation\, and the development of models that can be used in co
 mponent design.
LOCATION:JDB Seminar Room\, CUED
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