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.

A Computational Design Method for a Shape Memory Alloy Wire Actuated Compliant Finger

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Chao-Chieh Lan ◽  
You-Nien Yang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Design Method ◽  
Three Dimensional ◽  
Computational Design ◽  
Computational Method ◽  
Output Force ◽  
Robotic Manipulations ◽  
Experimental Validations ◽  
High Work

This paper presents a computational method to design a compliant finger for robotic manipulations. As traditional mechanical fingers require bulky electromagnetic 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 quiet operations. The combination of compliant members with embedded SMA wires makes the finger more compact and lightweight. Various SMA wire layouts are investigated to reduce 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 parametrization technique. We further illustrate our method by designing a humanoid finger that is capable of three-dimensional manipulation. Since compliant fingers can be fabricated monolithically, we expect the proposed design method to be utilized for applications of various scales.

Design and Optimization of a Shape Memory Alloy-Based Self-Folding Sheet

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Edwin Peraza-Hernandez ◽  
Darren Hartl ◽  
Edgar Galvan ◽  
Richard Malak
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Three Dimensional ◽  
Building Blocks ◽  
Passive Layer ◽  
Von Mises Stress ◽  
Maximum Temperature ◽  
Radius Of Curvature ◽  
Folding Angle ◽  
The Impact

Origami engineering—the practice of creating useful three-dimensional structures through folding and fold-like operations on two-dimensional building-blocks—has the potential to impact several areas of design and manufacturing. In this article, we study a new concept for a self-folding system. It consists of an active, self-morphing laminate that includes two meshes of thermally-actuated shape memory alloy (SMA) wire separated by a compliant passive layer. The goal of this article is to analyze the folding behavior and examine key engineering tradeoffs associated with the proposed system. We consider the impact of several design variables including mesh wire thickness, mesh wire spacing, thickness of the insulating elastomer layer, and heating power. Response parameters of interest include effective folding angle, maximum von Mises stress in the SMA, maximum temperature in the SMA, maximum temperature in the elastomer, and radius of curvature at the fold line. We identify an optimized physical realization for maximizing folding capability under mechanical and thermal failure constraints. Furthermore, we conclude that the proposed self-folding system is capable of achieving folds of significant magnitude (as measured by the effective folding angle) as required to create useful 3D structures.

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.

scholarly journals Optimization of MEMS Actuator Driven by Shape Memory Alloy Thin Film Phase Change

2020 ◽  
Author(s):  
Cory R. Knick
Keyword(s):  
Shape Memory Alloy ◽  
Phase Change ◽  
Shape Memory ◽  
Curvature Radius ◽  
Alloy Thin Film ◽  
Individual Layer ◽  
Cantilever Length ◽  
Stress Changes ◽  
Bimorph Actuators ◽  
High Work

At the microscale, shape memory alloy (SMA) microelectromechanical system (MEMS) bimorph actuators offer great potential based on their inherently high work density. An optimization problem relating to the deflection and curvature based on shape memory MEMS bimorph was identified, formulated, and solved. Thicknesses of the SU-8 photoresist and nickel-titanium alloy (NiTi) was identified that yielded maximum deflections and curvature radius based on a relationship among individual layer thicknesses, elastic modulus, and cantilever length. This model should serve as a guideline for optimal NiTi and SU-8 thicknesses to drive large deflections and curvature radius that are most suitable for microrobotic actuation, micromirrors, micropumps, and microgrippers. This model would also be extensible to other phase-change-driven actuators where nonlinear and significant residual stress changes are used to drive actuation.

scholarly journals An analytical model for crack monitoring of the shape memory alloy intelligent concrete

2019 ◽  
Vol 31 (1) ◽  
pp. 100-116 ◽  
Author(s):  
Bingfei Liu ◽  
Qingfei Wang ◽  
Kai Yin ◽  
Liwen Wang
Keyword(s):  
Shape Memory Alloy ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
One Dimensional ◽  
Monitoring Model ◽  
Crack Monitoring ◽  
The One

A theoretical model for the crack monitoring of the shape memory alloy intelligent concrete is presented in this work. The mechanical properties of shape memory alloy materials are first given by the experimental test. The one-dimensional constitutive model of the shape memory alloys is reviewed by degenerating from a three-dimensional model, and the behaviors of the shape memory alloys under different working conditions are then discussed. By combining the electrical resistivity model and the one-dimensional shape memory alloy constitutive model, the crack monitoring model of the shape memory alloy intelligent concrete is given, and the relationships between the crack width of the concrete and the electrical resistance variation of the shape memory alloy materials for different crack monitoring processes of shape memory alloy intelligent concrete are finally presented. The numerical results of the present model are compared with the published experimental data to verify the correctness of the model.

scholarly journals Modeling the behavior of bilayer shape memory alloy/functionally graded material beams considering asymmetric shape memory alloy response

2019 ◽  
Vol 31 (1) ◽  
pp. 84-99 ◽  
Author(s):  
Nguyen Van Viet ◽  
Wael Zaki ◽  
Rehan Umer ◽  
Quan Wang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Functionally Graded Material ◽  
Three Dimensional ◽  
Laminated Composite ◽  
Alloy Layer ◽  
Functionally Graded ◽  
Tension And Compression ◽  
Graded Material ◽  
Asymmetric Shape

A new model is proposed to describe the response of laminated composite beams consisting of one shape memory alloy layer and one functionally graded material layer. The model accounts for asymmetry in tension and compression of the shape memory alloy behavior and successfully describes the dependence of the position of the neutral surface on phase transformation within the shape memory alloy and on the load direction. Moreover, the model is capable of describing the response of the composite beam to both loading and unloading cases. In particular, the derivation of the equations governing the behavior of the beam during unloading is presented for the first time. The effect of the functionally graded material gradient index and of temperature on the neutral axis deviation and on the overall behavior of the beam is also discussed. The results obtained using the model are shown to fit three-dimensional finite element simulations of the same beam.

scholarly journals QUASISTATIC ISOTHERMAL EVOLUTION OF SHAPE MEMORY ALLOYS

2011 ◽  
Vol 21 (12) ◽  
pp. 2409-2432 ◽  
Author(s):  
SERGIO FRIGERI ◽  
PAVEL KREJČÍ ◽  
ULISSE STEFANELLI
Keyword(s):  
Weak Solution ◽  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Phenomenological Model ◽  
Three Dimensional ◽  
Time Discretization ◽  
Quasistatic Evolution ◽  
Asymmetric Behavior ◽  
Discretization Procedure

This paper focuses on a three-dimensional phenomenological model for the isothermal evolution of a polycrystalline shape memory alloy. The model, originally proposed by Auricchio, Taylor, and Lubliner in 1997, is thermodynamically consistent and reproduces the crucial martensitic reorientation effect as well as the tension-compression asymmetric behavior of the material. We prove the existence of a weak solution of the corresponding quasistatic evolution problem by passing to the limit within a time-discretization procedure.

Comparative study of two types of self-recovery shape-memory alloy pseudo-rubber isolator devices under compression–shear interactions

2019 ◽  
Vol 30 (15) ◽  
pp. 2241-2256 ◽  
Author(s):  
Suchao Li ◽  
Chenxi Mao
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shear Failure ◽  
Three Dimensional ◽  
Residual Deformation ◽  
Shear Loading ◽  
Wire Mesh ◽  
Type I ◽  
Rubber Isolator ◽  
Deformation Recovery

Two types of novel shape-memory alloy-based devices with three-dimensional isolation potential and deformation recovery abilities were developed. These two types of isolators, which are called shape-memory alloy pseudo-rubber isolators, were both created with martensitic shape-memory alloy wires through weaving, rolling, and punching processes, but they underwent heat treatment at different fabrication stages and for different durations. A series of mechanical tests were performed on these two types of shape-memory alloy pseudo-rubber isolators to investigate their properties under compression, shear, and combined compression–shear loading at room temperature. The restorable shear limit was then investigated, and the corresponding shear failure mechanism was discussed according to a tension test of one thin layer of the shape-memory alloy wire mesh. Subsequently, the deformation recovery ability of the shape-memory alloy pseudo-rubber isolator with residual deformation was tested through heating on a thermo-control stove. Finally, the mechanical-property stabilities, energy-dissipation abilities, and recovery abilities were compared between the two types of shape-memory alloy pseudo-rubber isolator devices. The experimental results indicated that both types of shape-memory alloy pseudo-rubber isolators had excellent residual deformation recovery abilities, and the type-I shape-memory alloy pseudo-rubber isolator device had more stable mechanical properties than the type-II shape-memory alloy pseudo-rubber isolator. The type-I shape-memory alloy pseudo-rubber isolator device is thus an ideal candidate for traditional three-dimensional isolators.

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