Influence of Strain Rate on Mechanical Properties of Shape Memory Alloy

2011 ◽  
Vol 467-469 ◽  
pp. 585-588 ◽  
Author(s):  
Zhen Qing Wang ◽  
Hong Shuai Lei ◽  
Bo Zhou ◽  
Yu Long Wang ◽  
Chen Zhang
Keyword(s):  
Mechanical Properties ◽  
Shape Memory Alloy ◽  
Strain Rate ◽  
Shape Memory ◽  
Critical Stress ◽  
Transformation Process ◽  
Test Results ◽  
Stress Strain ◽  
Loading Tests ◽  
New Equation

The influence of strain rate on mechanical properties of Ni-Ti SMA wires was investigated by a series of uniaxial loading tests. The influence of strain rate on critical stress was discussed. During the transformation process, the slop of the stress-strain curves was increasing with the increase of strain rate. A new equation was developed to describe the change of residual train based on the test results.

Experimental Study on Mechanical Properties of Large NiTi Superelastic Shape Memory Alloy Bars

2021 ◽  
Author(s):  
Qiujun Ning ◽  
Lihua Zhu ◽  
Wei Han ◽  
Cheng Zhao
Keyword(s):  
Mechanical Properties ◽  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Mechanical Performance ◽  
Engineering Application ◽  
Test Results ◽  
Equivalent Viscous Damping ◽  
Heat Treated ◽  
Strength And Stiffness

Abstract This study intensively examined the mechanical properties of large-sized superelastic shape memory alloy (SMA) bars, mainly focusing on their self-centering and energy dissipation capabilities. A detailed investigation on the effects of the heat treatment strategy, loading rate, strain amplitude, cyclic loading, prestress, and diameter of the SMA bars on their mechanical performance—residual strain, energy dissipation, equivalent viscous damping ratios, strength, and stiffness—was conducted. Furthermore, the fracture microstructure of monotonic tensile specimens was analyzed via scanning electron microscopy. The results indicated that the optimally heat-treated SMA bars show good superelasticity. The mechanical properties were relatively stable under constant strain loading–unloading training, which should be considered in engineering applications. The test results provided basic experimental data support for the engineering application of large SMA bars.

scholarly journals Influence of strain rate on mechanical properties of a CuAlMnTiB shape memory alloy

2021 ◽  
Author(s):  
Breno H.S. Andrade ◽  
David D.S. Silva ◽  
Ieverton C.A. Brito ◽  
Rafael E. Caluête ◽  
André R.R. Sousa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shape Memory Alloy ◽  
Strain Rate ◽  
Shape Memory

Effect of the strain rate and test temperature on the mechanical properties of a Ti-Ni-Fe shape memory alloy

2008 ◽  
Vol 2008 (1) ◽  
pp. 61-65
Author(s):  
N. N. Popov ◽  
I. I. Kaganova ◽  
L. V. Polyakov ◽  
A. M. Bragov ◽  
A. K. Lomunov
Keyword(s):  
Mechanical Properties ◽  
Shape Memory Alloy ◽  
Strain Rate ◽  
Shape Memory ◽  
Test Temperature

Experimental Study on the Mechanical Properties of Shape Memory Alloy

2015 ◽  
Vol 775 ◽  
pp. 204-208
Author(s):  
Cheng Xu ◽  
Qi Rong Zhu
Keyword(s):  
Mechanical Properties ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Strain Curve ◽  
Small Scale ◽  
Sample Material ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Alloy Material ◽  
Force Range

In this paper, the technology, equipment and method used to m easure the mechanical properties of micro-scale new-style intelligent shape memory alloy material were studied. First, two groups of small-scale shape memory alloy samples were made and the suitable micro load device was designed according to samples’ size and force range. Then the strain of the samples were observed with the video microscopy and calculated. Comparing with the corresponding force, the stress-strain curves of the two groups of samples were obtained respectively. After fitting these two curves, the stress-strain curve of the sample material was obtained. Finally, the basic mechanical properties of this shape memory alloy materials were discussed.

scholarly journals Experimental and Numerical Analysis of the Mechanical Properties of a Pretreated Shape Memory Alloy Wire in a Self-Centering Steel Brace

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 80
Author(s):  
Bo Zhang ◽  
Sizhi Zeng ◽  
Fenghua Tang ◽  
Shujun Hu ◽  
Qiang Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Loading Rate ◽  
Effective Elastic Modulus ◽  
Maximum Energy ◽  
Numerical Results ◽  
Energy Dissipation Capacity

As a stimulus-sensitive material, the difference in composition, fabrication process, and influencing factors will have a great effect on the mechanical properties of a superelastic Ni-Ti shape memory alloy (SMA) wire, so the seismic performance of the self-centering steel brace with SMA wires may not be accurately obtained. In this paper, the cyclic tensile tests of a kind of SMA wire with a 1 mm diameter and special element composition were tested under multi-working conditions, which were pretreated by first tensioning to the 0.06 strain amplitude for 40 cycles, so the mechanical properties of the pretreated SMA wires can be simulated in detail. The accuracy of the numerical results with the improved model of Graesser’s theory was verified by a comparison to the experimental results. The experimental results show that the number of cycles has no significant effect on the mechanical properties of SMA wires after a certain number of cyclic tensile training. With the loading rate increasing, the pinch effect of the hysteresis curves will be enlarged, while the effective elastic modulus and slope of the transformation stresses in the process of loading and unloading are also increased, and the maximum energy dissipation capacity of the SMA wires appears at a loading rate of 0.675 mm/s. Moreover, with the initial strain increasing, the slope of the transformation stresses in the process of loading is increased, while the effective elastic modulus and slope of the transformation stresses in the process of unloading are decreased, and the maximum energy dissipation capacity appears at the initial strain of 0.0075. In addition, a good agreement between the test and numerical results is obtained by comparing with the hysteresis curves and energy dissipation values, so the numerical model is useful to predict the stress–strain relations at different stages. The test and numerical results will also provide a basis for the design of corresponding self-centering steel dampers.

scholarly journals Effect of Nanopores on Mechanical Properties of the Shape Memory Alloy

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 529
Author(s):  
Chunzhi Du ◽  
Zhifan Li ◽  
Bingfei Liu
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Shape Memory ◽  
Young’S Modulus ◽  
Residual Strain ◽  
Surface Effect ◽  
Young's Modulus ◽  
Strain Curve ◽  
Stress Strain ◽  
Strength Limit

Nanoporous Shape Memory Alloys (SMA) are widely used in aerospace, military industry, medical and health and other fields. More and more attention has been paid to its mechanical properties. In particular, when the size of the pores is reduced to the nanometer level, the effect of the surface effect of the nanoporous material on the mechanical properties of the SMA will increase sharply, and the residual strain of the SMA material will change with the nanoporosity. In this work, the expression of Young’s modulus of nanopore SMA considering surface effects is first derived, which is a function of nanoporosity and nanopore size. Based on the obtained Young’s modulus, a constitutive model of nanoporous SMA considering residual strain is established. Then, the stress–strain curve of dense SMA based on the new constitutive model is drawn by numerical method. The results are in good agreement with the simulation results in the published literature. Finally, the stress-strain curves of SMA with different nanoporosities are drawn, and it is concluded that the Young’s modulus and strength limit decrease with the increase of nanoporosity.

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