BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Design of microstructures for enhanced magnetostriction in active 
 composites - Professor Pedro Ponte\, University of pennsylvania\, School o
 f Engineering and Applied Science
DTSTART:20141107T140000Z
DTEND:20141107T150000Z
UID:TALK54797@talks.cam.ac.uk
CONTACT:Ms Helen Gardner
DESCRIPTION:Magnetoactive elastomers (MAEs) are composite materials consis
 ting of nearly rigid\, magnetically susceptible particles embedded in a so
 ft\, magnetically insensitive elastomer matrix. These multi-functional mat
 erials exhibit field-dependent strains and changes in stiffness. However\,
  the strains that have been achieved experimentally to date are still rela
 tively small (of the order of 1%). The reason for these small strains can 
 be traced back to the dipolar nature of the forces between particles. Larg
 e particle concentrations are required to generate strong forces\, but lar
 ge concentrations also lead to large overall stiffness for the composite m
 aterial\, which\, in turn\, tends to reduce the overall strain. In this pr
 esentation\, we explore the possible use of magnetic torques on the partic
 les for enhanced magnetostriction. We exploit such magnetic torques in the
  context of a multi-scale homogenization analysis to optimally design a ne
 w class of MAEs with doubly layered\, herringbone-type microstructures cap
 able of generating much larger field-induced strains of up to 100%. This i
 s accomplished by combining the strong action of magnetic torques on suita
 bly oriented magnetic layers\, which interact directly with the applied ma
 gnetic field\, together with the excitation of soft modes of simple shear 
 deformation in the elastomer layers. Theoretical predictions\, based on an
  exact analytical solution for the macroscopic magnetoelastic response of 
 the materials\, allow for the optimization of the microstructure for enhan
 ced magnetostriction. Time permitting\, we will also address the possible 
 development of long-wavelength instabilities in such magnetoelastic compos
 ites.
LOCATION:Oatley Seminar Room\, Department of Engineering
END:VEVENT
END:VCALENDAR