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SUMMARY:MEchanics GAthering -MEGA- Seminar: Modeling and identification of
  constitutive behavior for magnetorheological elastomers
DTSTART:20190502T161500
DTEND:20190502T173000
DTSTAMP:20260510T164823Z
UID:b64057fd032d65504310aa7d1011a3d9412ad43f2e12367e835e42f6
CATEGORIES:Conferences - Seminars
DESCRIPTION:Nicolas Triantafyllidis\, LMS\, École Polytechnique\nMagneto
 rheological elastomers (MREs) are ferromagnetic particle impregnated rubbe
 rs whose mechanical properties are altered by the application of external 
 magnetic fields. Due to their strong magnetoelastic coupling response\, MR
 Es are finding an increasing number of engineering applications\, thus nec
 essitating accurate techniques for the determination of their effective pr
 operties. This is a difficult task since the overall response of an MRE sa
 mple does not only depend on the properties of its constituent materials (
 and its respective microscopic architecture)\, but also on its shape: an M
 RE specimen is subjected to Maxwell stresses that exist both inside the MR
 Es and the surrounding air\, leading to shape-dependent non-uniform stress
  fields inside the specimen.\n\nThe goal of this work is a combined experi
 mental and 3D finite element (FEM) modeling approach for computing (and su
 bsequently validating) the energy density for MREs that is not biased by t
 he above-mentioned shape effect. We focus here on isotropic MREs with a fi
 xed volume fraction of particles (8.7%)\, investigated based on a novel ex
 perimental technique. Using a variational framework for finitely strained 
 MREs\, we present and subsequently implement into an FEM code three differ
 ent (but equivalent) variational formulations based on different choices o
 f the independent magnetic variable of the free energy function. Using FEM
  simulations\, necessary to account for the shape effect observed in exper
 iments conducted with a specially designed setup at the LMS at Polytechniq
 ue\, the data obtained from the purely magnetostrictive test are used to f
 it the three equivalent free energy functions for the isotropic MRE of int
 erest. The thus obtained constitutive models give accurate predictions whe
 n used to simulate different (i.e. not used in the constitutive fitting pr
 ocess) magnetostrictive experiments under axial tension. Time permitting s
 ome additional MRE applications will also be presented.\n\nThis is joint w
 ork with my colleagues Profs. K. Danas\, L. Bodelot and Dr. J-P. Voropaief
 f.
LOCATION:MED 2 2423 https://plan.epfl.ch/?room=MED22423
STATUS:CONFIRMED
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