TY - JOUR
T1 - Deformation of extreme viscoelastic metals and composites
AU - Wang, Y. C.
AU - Ludwigson, M.
AU - Lakes, R. S.
N1 - Funding Information:
The authors are grateful for a grant, CMS-9896284, from NSF and for the NSF-REU program. We thank B. Welbes and C. Marquez for assistance in preparing specimens and W. Drugan and R. Cooper for helpful comments and discussion.
PY - 2004/4/15
Y1 - 2004/4/15
N2 - The figure of merit for structural damping and damping layer applications is the product of stiffness E and damping tan δ. For most materials, even practical polymer damping layers, E tan δ is less than 0.6 GPa. We consider several methods to achieve high values of this figure of merit: high damping metals, metal matrix composites and composites containing constituents of negative stiffness. As for high damping metals, damping of polycrystalline zinc was determined and compared with InSn studied earlier. Damping of Zn is less dependent on frequency than that of InSn, so Zn is superior at high frequency. High damping and large stiffness anomalies are possible in viscoelastic composites with inclusions of negative stiffness. Negative stiffness entails a reversal of the usual directional relationship between force and displacement in deformed objects. An isolated object with negative stiffness is unstable, but an inclusion embedded in a composite matrix can be stabilized under some circumstances. Ferroelastic domains in the vicinity of a phase transition can exhibit a region of negative stiffness. Metal matrix composites containing vanadium dioxide were prepared and studied. The concentration of embedded particles was sensitive to the processing method.
AB - The figure of merit for structural damping and damping layer applications is the product of stiffness E and damping tan δ. For most materials, even practical polymer damping layers, E tan δ is less than 0.6 GPa. We consider several methods to achieve high values of this figure of merit: high damping metals, metal matrix composites and composites containing constituents of negative stiffness. As for high damping metals, damping of polycrystalline zinc was determined and compared with InSn studied earlier. Damping of Zn is less dependent on frequency than that of InSn, so Zn is superior at high frequency. High damping and large stiffness anomalies are possible in viscoelastic composites with inclusions of negative stiffness. Negative stiffness entails a reversal of the usual directional relationship between force and displacement in deformed objects. An isolated object with negative stiffness is unstable, but an inclusion embedded in a composite matrix can be stabilized under some circumstances. Ferroelastic domains in the vicinity of a phase transition can exhibit a region of negative stiffness. Metal matrix composites containing vanadium dioxide were prepared and studied. The concentration of embedded particles was sensitive to the processing method.
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U2 - 10.1016/j.msea.2003.08.071
DO - 10.1016/j.msea.2003.08.071
M3 - Article
AN - SCOPUS:1842636913
SN - 0921-5093
VL - 370
SP - 41
EP - 49
JO - Materials Science and Engineering A
JF - Materials Science and Engineering A
IS - 1-2
ER -