The pseudoelastic hysteresis behavior of shape memory alloy (SMA) elements observed above the austenite finish temperature of the alloy, can be used to provide a large structural damping in different applications. In this work, the pseudoelastic damping capacity (SDC) of a NiTi SMA wire has been characterized using the complex modulus approach through testing under a dynamic tensile condition. A test setup has been specifically designed, built and validated for this measurement since a testing machine with the required performances was not available. Given the dynamic characteristic of the test the structure was designed to behave as a rigid body in the frequency range of interest. Different conditions have been tested, varying the excitation frequency, the amplitude of imposed deformation, and the pre-strain levels. Results show that the SDC has a nearly constant trend of 7.5% for low frequencies until 30 Hz. Moreover, variation of the amplitude of deformation, between 0.3% and 0.8%, causes an increasing of the damping capacity, which varies from 7.7% to 10.4%, respectively. Finally, the measured prestrain amplitude effect is in agreement with existing literature studies.
Characterization of the pseudoelastic damping capacity of shape memory alloy wire
Saggin B.;
2017
Abstract
The pseudoelastic hysteresis behavior of shape memory alloy (SMA) elements observed above the austenite finish temperature of the alloy, can be used to provide a large structural damping in different applications. In this work, the pseudoelastic damping capacity (SDC) of a NiTi SMA wire has been characterized using the complex modulus approach through testing under a dynamic tensile condition. A test setup has been specifically designed, built and validated for this measurement since a testing machine with the required performances was not available. Given the dynamic characteristic of the test the structure was designed to behave as a rigid body in the frequency range of interest. Different conditions have been tested, varying the excitation frequency, the amplitude of imposed deformation, and the pre-strain levels. Results show that the SDC has a nearly constant trend of 7.5% for low frequencies until 30 Hz. Moreover, variation of the amplitude of deformation, between 0.3% and 0.8%, causes an increasing of the damping capacity, which varies from 7.7% to 10.4%, respectively. Finally, the measured prestrain amplitude effect is in agreement with existing literature studies.Pubblicazioni consigliate
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