Test Method for Mechanical Uniaxial Constant Force Thermal Cycling of Shape Memory Alloys

2017 ◽  
Author(s):  
Keyword(s):  
Shape Memory Alloys ◽  
Thermal Cycling ◽  
Shape Memory ◽  
Test Method ◽  
Constant Force

The study for constant force characteristic of C-shaped superelastic SMA

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1253-1259
Author(s):  
Minghui Wang ◽  
Hongliu Yu
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Medical Device ◽  
Soft Tissues ◽  
Computational Simulation ◽  
Force Characteristic ◽  
Constant Force ◽  
Curve Shape ◽  
Artificial Sphincter ◽  
Round Bar

Clamping devices with constant force or pressure are desired in medical device, such as hemostatic forceps and the artificial sphincter, to prevent soft tissues from injures due to overloading. It is easily obtained by stretching an SMA wire. However, studies with SMA bending round bar have seldom been reported before. This paper studied constant force characteristic of C-shaped round bar with shape memory alloys. Optimization designs of the components were carried out with computational simulation. Numerical results show that the phenomenon of constant force strongly depends on contour curve shape and geometric dimensions of the C-shaped round bar of SMA component.

scholarly journals An energy-flexible mechanism for qPCR thermal cycling using shape memory alloys

2020 ◽  
Vol 29 (4) ◽  
pp. 045038
Author(s):  
Ryan Snodgrass ◽  
Duncan McCloskey ◽  
Paul Benecke ◽  
David Erickson
Keyword(s):  
Shape Memory Alloys ◽  
Thermal Cycling ◽  
Shape Memory ◽  
Flexible Mechanism

scholarly journals Characterization of Ternary NiTiPd High-Temperature Shape-Memory Alloys under Load-Biased Thermal Cycling

2010 ◽  
Vol 41 (12) ◽  
pp. 3065-3079 ◽  
Author(s):  
Glen S. Bigelow ◽  
Santo A. Padula ◽  
Anita Garg ◽  
Darrell Gaydosh ◽  
Ronald D. Noebe
Keyword(s):  
High Temperature ◽  
Shape Memory Alloys ◽  
Thermal Cycling ◽  
Shape Memory

Microstructural Irreversibilities under Thermal Cycling in Ni-Ti-Fe Shape Memory Alloys

2011 ◽  
Vol 702-703 ◽  
pp. 888-891 ◽  
Author(s):  
Ritwik Basu ◽  
Lokendra Jain ◽  
Bikas Maji ◽  
Madangopal Krishnan ◽  
Karri V. Mani Krishna ◽  
...  
Keyword(s):  
Shape Memory Alloys ◽  
Thermal Cycling ◽  
Shape Memory ◽  
Room Temperature ◽  
Residual Deformation ◽  
Austenite Grain Size ◽  
Reversible Transformation ◽  
Martensite Content ◽  
Austenite Grain ◽  
Grain Misorientation

The thermal cycling (quenching in liquid nitrogen and reverting back to room temperature: austenite martensite reversible transformation) response of Ni-Ti-Fe shape memory alloys has been investigated. It was clearly noted that residual deformation, estimated in terms of noticeable differences in austenite grain size, depend on the relative clustering of fine grains. During repeated thermal cycling, the residual deformation, in-grain misorientation developments and retained martensite content scaled together: bringing out a clear picture of microstructural irreversibility.

Modeling of Cyclic Response of High Temperature Shape Memory Alloys Undergoing Viscoplastic Mechanisms

2010 ◽  
Author(s):  
George Chatzigeorgiou ◽  
Yves Chemisky ◽  
Dimitris C. Lagoudas
Keyword(s):  
High Temperature ◽  
Shape Memory Alloys ◽  
Thermal Cycling ◽  
Shape Memory ◽  
Heating Rate ◽  
Evolution Equations ◽  
Experimental Tests ◽  
Energy Potential ◽  
Slow Cooling ◽  
Cyclic Response

In this work we present a constitutive model for High Temperature Shape Memory Alloys (HTSMAs), where the appearence of viscoplastic mechanisms during transformation influences the cyclic response of the actuator performance. Based on previous models developed for conventional SMAs, a Gibbs free energy potential is defined and the evolution equations for forward, reverse transformation, plasticity occuring during transformation, retained martensite and viscoplasticity are properly chosen. The calibration of the model is achieved with the help of experimental tests performed on TiPdNi alloy. The transformation behavior of the material is calibrated using fast load biased thermal cycling tests at selected stress levels with fast cooling/heating rate. The viscoplastic behavior of the HTSMA is captured with creep and uniaxial tests at appropriate temperature levels. Predictions of the model are compared with load biased thermal cycling tests at slow cooling/heating rate, where viscoplastic strains are significant.

scholarly journals Study of Dislocations Generated by Thermal Cycling in Ni-Ti-Co Shape Memory Alloys

1995 ◽  
Vol 05 (C2) ◽  
pp. C2-293-C2-298
Author(s):  
J. Pons ◽  
L. Jordan ◽  
J. P. Morniroli ◽  
R. Portier
Keyword(s):  
Shape Memory Alloys ◽  
Thermal Cycling ◽  
Shape Memory
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