scholarly journals Design Method for Constant Force Components Based on Superelastic SMA

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2842 ◽  
Author(s):  
Minghui Wang ◽  
Hongliu Yu ◽  
Ping Shi ◽  
Qiaoling Meng
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Large Deformation ◽  
Soft Tissues ◽  
Design Method ◽  
Alloy Sheet ◽  
Constant Force ◽  
Artificial Sphincter ◽  
Medical Instruments ◽  
Force Components

Clamping devices with constant force or pressure are desired in medical instruments, such as hemostatic forceps and the artificial sphincter, to prevent soft tissues from injures due to overloading. This paper studies the design method issues in constant force components using superelastic shape memory alloy. A generalized method for generating a constant force components-based shape memory alloy is proposed. An example of a C-shaped shape memory alloy sheet with a thickness of 0.2 mm is presented. The design results using the generalized design method for a C-shaped shape memory alloy sheet with 0.2 mm thickness are compared with its experimental results. Based on the generalized design method, the obtained design solutions for Cases 1 and 2 are coincident with the results obtained by the experiments. It could be seen that the generated design shape of the superelastic shape memory alloy component might obtain constant force within a relatively large deformation range. It is validated that the proposed generalized design method was feasible and effective. It is also illustrated that changing the geometric dimensions of the superelastic SMA component might obtain constant force within a relatively large deformation range.

DESIGN OPTIMIZATION OF C-SHAPED SUPERELASTIC SMA SHEET WITH CONSTANT FORCE

2018 ◽  
Vol 18 (01) ◽  
pp. 1750064 ◽  
Author(s):  
MINGHUI WANG ◽  
HONGLIU YU ◽  
BAOLIN LIU ◽  
LIANGFAN ZHU ◽  
YUN LUO
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Large Deformation ◽  
Soft Tissues ◽  
Alloy Sheet ◽  
Experimental Results ◽  
Constant Force ◽  
Force Component ◽  
Element Analysis ◽  
Initial Shape

Constant force component is very useful in medical device, such as forceps with constant force, which may prevent soft tissues from injures due to overloading. This paper studied the optimization procedure in constant force component for superelastic shape memory alloy, and tried to find the rule of obtaining constant force within a relatively large deformation range for superelastic C-shaped shape memory alloy sheet. The optimization concept of combing finite element analysis in ANSYS with genetic algorithm in MATLAB was presented for designing constant force component using superelastic SMA. The computational optimization and experimental results of the C-shaped shape memory alloy sheet showed that the proposed optimization method was potential for superelastic shape memory alloy. The optimization results were consistent with the experimental results. It was demonstrated that constant force could be obtained within a relatively large deformation range by varying the initial shape of the superelastic SMA component.

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.

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.

Experimental and numerical studies on a novel shape-memory alloy wire–woven trusses capable of undergoing large deformation

2019 ◽  
Vol 30 (15) ◽  
pp. 2283-2298
Author(s):  
Zhixiang Rao ◽  
Xiaojun Yan ◽  
Xiaoyong Zhang ◽  
Bin Zhang ◽  
Jun Jiang ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Large Deformation ◽  
Residual Deformation ◽  
Shape Memory Alloy Wire ◽  
Static Compression ◽  
Recoverable Strain ◽  
Alloy Wire ◽  
Assembly Method ◽  
Finite Element Analysis Simulation

Currently, most wire-woven trusses are fabricated with traditional metals such as steel and aluminum, thus the deformation ability is constrained due to the low yield strain of common metals. Shape-memory alloy is a kind of smart material which can bear large recoverable strain while producing hysteresis. Due to the unique capacity of large deformation and remarkable damping property of the shape-memory alloy, a novel lattice trusses assembled by superelastic shape-memory alloy coil springs was proposed. Furthermore, the treatment processes to prepare the shape-memory alloy coil springs and the assembly method to fabricate the shape-memory alloy wire–woven trusses were also introduced. The quasi-static compression under different maximum deformation and temperatures was performed to investigate the mechanical and thermal responses of the proposed shape-memory alloy wire–woven trusses. Cyclic compression tests were also performed to study the functional fatigue of the shape-memory alloy wire–woven trusses. The proposed wire-woven trusses can undergo up to 80% deformation by compression and recover without evident residual deformation after unloading. Finite element analysis simulation of representative volume element under different deformation was presented. Analytical modeling of the stiffness of shape-memory alloy wire–woven trusses was also carried out. Both the numerical and analytical methods can predict the stiffness within a small deviation.

Effect of texture orientation on the martensite deformation of NiTi shape memory alloy sheet

1999 ◽  
Vol 47 (2) ◽  
pp. 645-660 ◽  
Author(s):  
Y. Liu ◽  
Z.L. Xie ◽  
J. Van Humbeeck ◽  
L. Delaey
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Alloy Sheet ◽  
Niti Shape Memory Alloy ◽  
Texture Orientation

An Analytical Design Method for a Shape Memory Alloy Wire Actuated Compliant Finger

2008 ◽  
Author(s):  
Chao-Chieh Lan ◽  
You-Nien Yang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Design Method ◽  
Three Dimensional ◽  
Output Force ◽  
Shape Parameterization ◽  
Robotic Manipulations ◽  
Experimental Validations ◽  
Electro Magnetic ◽  
High Work

This paper presents an analytical method to design a mechanical finger for robotic manipulations. As traditional mechanical fingers require bulky electro-magnetic motors and numerous relative-moving parts to achieve dexterous motion, we propose a class of fingers the manipulation of which relies on finger deflections. These compliant fingers are actuated by shape memory alloy (SMA) wires that exhibit high work-density, frictionless, and quite operations. The combination of compliant members with embedded SMA wires makes the finger more compact and lightweight. Various SMA wire layouts are investigated to improve their response time while maintaining sufficient output force. The mathematical models of finger deflection caused by SMA contraction are then derived along with experimental validations. As finger shapes are essential to the range of deflected motion and output force, we find its optimal initial shapes through the use of a shape parameterization technique. We further illustrate our method by designing a humanoid finger that is capable of three-dimensional manipulation. As compliant fingers can be fabricated monolithically, we expect the proposed method to be utilized for applications of various scales.

scholarly journals 519 Development of an Artificial Sphincter Using Shape Memory Alloy

2000 ◽  
Vol 2000.35 (0) ◽  
pp. 194-195
Author(s):  
Hirokazu NAKAMURA ◽  
Toshiyuki TAKAGI ◽  
Yun LUO ◽  
Shintaro AMAE ◽  
Tomoyuki YANBE ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Artificial Sphincter

FlexLegs: Flexible Legs Actuated by Shape Memory Alloy

2011 ◽  
Author(s):  
Alex Villanueva ◽  
Colin Smith ◽  
Shashank Priya ◽  
Richard Bachman
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Large Deformation ◽  
Maximum Force ◽  
Maximum Deformation

A flexible leg (FlexLeg) design using BiFlex actuators was designed, fabricated and characterized. BISMAC actuators are unidirectional flexible actuators capable of exhibiting high curvature. These actuators were modified to achieve bidirectional deformation. The new bidirectional actuators termed as “BiFlex” actuators, have proven the capability to achieve large deformation in two directions. The FlexLegs consist of six segments which can be actuated individually. Two different sets of legs were constructed to determine the effect of size. The small legs measure 35.8 mm in height and 63.2 mm in width and the large legs were 97.4 mm in height and 165.4 mm in width. The small FlexLegs achieved a maximum deformation of 12% and 4% in the x- and y-direction respectively using a power of 0.7 W while producing a maximum force of 0.023 N. They were also able to withstand a load of 1.18 N. The large FlexLegs had a maximum deformation of 57% and 39% in the x- and y-direction respectively using a power of 3 W while producing a force of 0.045 N. They were able to withstand a load of 0.25 N. The legs were also able to perform several walking algorithms consisting of stepping, crabbing and yawing.

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