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Dynamic Characterization of Bi-material Cantilevers

Authors:
Roy Bijster
Jan de Vreugd
Hamed Sadeghian

Keywords: bilayer cantilevers; characterization; diffusivity

Abstract:
In this paper, an experimental-theoretical method is proposed to accurately determine the thermal diffusivity, characteristic time constant and layer thicknesses of a bimaterial cantilever using a transient, non-destructive and noncontact measurement. The technique is based on the wellknown optical beam deflection method. A time dependent, sinusoidal heat load is locally applied to induce a time varying thermal profile over the length of the beam, resulting in a mismatch-strain between the two layers that bends the cantilever. A measurement of the phase difference between the thermo-mechanical response and the input signal can be used to extract the thermal diffusivity, characteristic time constant and the location of the heat source. For this reason a closed form analytical solution for the thermo-echanical response is presented. The dynamic response of the system is characterized using the transfer function in the Laplace domain. The analytical solution includes a Gaussian distributed, time-dependent heat source of known width at a location long the beam. A constant convective heat transfer coefficient can be included to allow measurement in ambient conditions. A combination of a measurement of the thermal diffusivity and the effective conductance are used to calculate the mutual layer thicknesses of the two layers.

Pages: 1 to 8

Copyright: Copyright (c) IARIA, 2013

Publication date: August 25, 2013

Published in: conference

ISSN: 2308-3514

ISBN: 978-1-61208-297-4

Location: Barcelona, Spain

Dates: from August 25, 2013 to August 31, 2013