Design of Shape Memory Alloy Springs With Applications in Vibration Control

1993 ◽  
Vol 115 (1) ◽  
pp. 129-135 ◽  
Author(s):  
C. Liang ◽  
C. A. Rogers
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Vibration Control ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Design Method ◽  
Control Area ◽  
Spring Constant ◽  
Damping Capacity

Shape memory alloys (SMAs) have several unique characteristics, including their Young’s modulus-temperature relations, shape memory effects, and damping characteristics. The Young’s modulus of the high-temperature austenite of SMAs is about three to four times as large as that of low-temperature martensite. Therefore, a spring made of shape memory alloy can change its spring constant by a factor of three to four. Since a shape memory alloy spring can vary its spring constant, provide recovery stress (shape memory effect), or be designed with a high damping capacity, it may be useful in adaptive vibration control. Some vibration control concepts utilizing the unique characteristics of SMAs will be presented in this paper. Shape memory alloy springs have been used as actuators in many applications although their use in the vibration control area is very recent. Since shape memory alloys differ from conventional alloy materials in many ways, the traditional design approach for springs is not completely suitable for designing SMA springs. Some design approaches based upon linear theory have been proposed for shape memory alloy springs. A more accurate design method for SMA springs based on a new nonlinear thermomechanical constitutive relation of SMA is also presented in this paper.

Nucleation of martensite and thermal hysteresis of the young’s modulus in a Ni50.8Ti49.2 shape memory alloy

1999 ◽  
Vol 41 (11) ◽  
pp. 1211-1216 ◽  
Author(s):  
R. Campanella ◽  
B. Coluzzi ◽  
A. Biscarini ◽  
L. Trotta ◽  
G. Mazzolai ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Young’S Modulus ◽  
Thermal Hysteresis ◽  
Young's Modulus

The Effect of Non-Constant Young's Modulus in Modelling of Tension and Compression of Superelastic NI-TI Shape Memory Alloys

2010 ◽  
Vol 26 (4) ◽  
pp. 553-561
Author(s):  
Andrej Puksic ◽  
Janez Kunavar ◽  
Miha Brojan ◽  
Franc Kosel
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Transformation Strain ◽  
Material Model ◽  
Stress Plateau ◽  
Micromechanical Approach ◽  
Tension And Compression ◽  
Tension Compression Asymmetry

ABSTRACTMany unresolved issues remain in the field of modelling of shape memory alloys. In this paper the problem of unequal elastic properties of austenite and martensite is addressed. We propose a modification of the micromechanical material model that enables the application of different Young's modulus for austenite and martensite. The corresponding computational model for the application of the micromechanical approach to modeling of superelasticity in shape memory alloys is demonstrated. Material properties for Ni-Ti alloy (50.8 at.% Ni) obtained from literature and from our own experiments were applied to the model and a sample calculation of a 3D model subjected to uniaxial loading was performed. The results were compared to experimental results obtained from tensile and compressive tests. In general the presented model predicts well the level of the superelastic stress plateau and maximum transformation strain in tension. The agreement in compression is worse but the overall characteristics of the tension-compression asymmetry are predicted correctly.

Shape-memory coaxial bimorphs

2009 ◽  
Vol 223 (11) ◽  
pp. 2713-2716 ◽  
Author(s):  
R Jähne ◽  
L F Campanile
Keyword(s):  
Finite Element ◽  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Recovery ◽  
Design Method ◽  
Smart Structures ◽  
Finite Element Simulations ◽  
Alloy Component ◽  
Linear Elastic

The thermal shape recovery shown by shape memory alloys is a property that makes these materials very attractive for applications in the field of smart structures, e.g. bending actuators. This article shows a design method for coaxial bimorphs that are composed of a linear-elastic and shape memory alloy component, properly coupled. A simple and effective method is proposed to solve for the component designs in order to achieve given bimorph configurations. Analytical examples and finite-element simulations are shown for the case of assigned bimorph's warm shape.

Design, analysis, and manufacture of a tension–compression self-centering damper based on energy dissipation of pre-stretched superelastic shape memory alloy wires

2017 ◽  
Vol 28 (15) ◽  
pp. 2129-2139 ◽  
Author(s):  
Amin Alipour ◽  
Mahmoud Kadkhodaei ◽  
Mohsen Safaei
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Damping Ratio ◽  
Dissipated Energy ◽  
Damping Capacity ◽  
Compression Tests ◽  
Mechanical Unloading ◽  
Tension And Compression ◽  
The Individual

Superelastic shape memory alloys dissipate significant amount of energy since they recover large transformation strains upon mechanical unloading. Due to their dissipation properties, shape memory alloys can be effectively employed as dampers. Design, simulation, and fabrication of a newly developed superelastic shape memory alloy damper are discussed in this article. To enhance the stroke and dissipation capacity of the proposed damper, a system is implemented which operates more efficiently than a single shape memory alloy wire. Although shape memory alloy wires can only undergo tension, the new system enables the damper to be loaded in both tension and compression. Two damping groups are employed in this mechanism: one of which is activated during tension and the other is activated during compression of the damper. Each damping group consists of two shape memory alloy wires acting in the opposite directions to increase the damping capacity of the system. The mechanical responses of the individual components as well as the assembled damper are simulated. The predicted performance of the damper is then validated through tension/compression tests on the fabricated sample. Numerical and experimental force–displacement curves are also shown to be in a good agreement. The effect of different parameters on damping ratio and dissipated energy of the presented damper is investigated.

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