Magnetic Field Controlled Damping in MSM-Polymer Hybrids
I. Aaltio, F. Nilsén, J. Lehtonen, Y. Ge, S.-P. Hannula
Aalto University, Espoo, Finland
In addition to the well-known actuation property Magnetic Shape Memory (MSM) alloys have been found to have good vibration damping properties in particular in the low to moderate frequency range. The high vibration damping capability in MSMAs is based primarily on the hysteretic motion of martensite twin boundaries or on the reversible stress-induced-intermartensitic transformation. Both of these mechanisms enable several percent mechanical shape change of MSM material. Single crystal Ni-Mn-Ga MSM materials have been widely studied and used for their high capability of relative shape change. However, the size and shape of these single crystal is limited, e.g., due to the complex manufacturing process and the need of special methods for their cutting. In addition the material price is rather high for many damping applications. These limitations may be overcome by
an alternative approach: the MSM-polymer hybrids.
We studied the vibration damping properties of MSM-polymer hybrid composites and the effect of external magnetic field on damping. The Ni-Mn-Ga MSM material was produced by gas-atomization method and the resulting powder consisted of spherical particles of approximately 100 μm diameter. The MSM powder was mixed with epoxy and oriented by external magnetic field at the curing stage of the polymer matrix. The resulting hybrid material consisted of chains of MSM particles aligned with the magnetic field direction, which results to anisotropic mechanical and damping properties of the hybrid. Vibration damping properties of the hybrids were characterized. The properties of the hybrid depend on the filling ratio as well as the matrix material used. Application of the MSM-polymer hybrids to magnetically controllable vibration dampers is also briefly discussed.
ACTUATOR 2016 Manuscript A3.8
Publication date: 01/06/2016
Manuscript A3.8 published in Conference Proceedings ACTUATOR 2016
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