Construction of Thermo-Mechanical Coupling Analysis Model for Transient Characteristic Improvement for Shape Memory Alloy Actuator

2018 ◽  
Vol 2018.67 (0) ◽  
pp. 211
Author(s):  
Keisuke SUGITA ◽  
Kikuko MIYATA ◽  
Susumu HARA ◽  
Tadashige IKEDA
Author(s):  
Thiago Barbosa ◽  
Jés de Jesus Fiais Cerqueira ◽  
Antonio Marcus Nogueira Lima

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3026
Author(s):  
Minjae Lee ◽  
Sukwon Lee ◽  
Sungjoon Lim

Electromagnetic responses are generally controlled electrically or optically. However, although electrical and optical control allows fast response, they suffer from switching or tuning range limitations. This paper controls electromagnetic response by mechanical transformation. We introduce a novel kirigami-inspired structure for mechanical transformation with less strength, integrating a shape memory alloy actuator into the kirigami-inspired for mechanical transformation and hence electromagnetic control. The proposed approach was implemented for a reconfigurable antenna designed based on structural and electromagnetic analyses. The mechanical transformation was analyzed with thermal stimulus to predict the antenna geometry and electromagnetic analysis with different geometries predicted antenna performance. We numerically and experimentally verified that resonance response was thermally controlled using the kirigami-inspired antenna integrated with a shape memory alloy actuator.


2011 ◽  
Vol 172-174 ◽  
pp. 37-42 ◽  
Author(s):  
Yong Jun He ◽  
Qing Ping Sun

High damping capacity is one of the prominent properties of NiTi shape memory alloy (SMA), having applications in many engineering devices to reduce unwanted vibrations. Recent experiments demonstrated that, the hysteresis loop of the stress-strain curve of a NiTi strip/wire under a tensile loading-unloading cycle changed non-monotonically with the loading rate, i.e., a maximum damping capacity was obtained at an intermediate strain rate (ε.critical). This rate dependence is due to the coupling between the temperature dependence of material’s transformation stresses, latent-heat release/absorption in the forward/reverse phase transition and the associated heat exchange between the specimen and the environment. In this paper, a simple analytical model was developed to quantify these thermo-mechanical coupling effects on the damping capacity of the NiTi strips/wires under the tensile loading-unloading cycle. We found that, besides the material thermal/mechanical properties and specimen geometry, environmental condition also affects the damping capacity; and the critical strain rate ε.criticalfor achieving a maximum damping capacity can be changed by varying the environmental condition. The theoretical predictions agree quantitatively with the experiments.


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