Conglomerate Stabilization Curve Design Method for Shape Memory Alloy Wire Actuators With Cyclic Shakedown

2011 ◽  
Vol 133 (11) ◽  
Author(s):  
WonHee Kim ◽  
Brian M. Barnes ◽  
Jonathan E. Luntz ◽  
Diann E. Brei
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Design Method ◽  
Mechanical Strain ◽  
High Energy ◽  
Design Guidelines ◽  
High Energy Density ◽  
Interface Position ◽  
Curve Design ◽  
Actuation Strain

The high energy density actuation potential of shape memory alloy (SMA) wire is tempered by conservative design guidelines set to mitigate complex factors such as functional fatigue (shakedown). In addition to stroke loss, shakedown causes practical problems of interface position drift between the system and the SMA wire under higher stress levels if the wire does not undergo a pre-installation shakedown procedure. Constraining actuation strain eliminates interface position drift and has been reported to reduce shakedown as well as increase fatigue life. One approach to limit actuation strain is using a mechanical strain limiter, which sets a fixed Martensite strain position—useful for the development of in-device shakedown procedures, which eliminates time-consuming pre-installation shakedown procedures. This paper presents a novel conglomerate stabilization curve design method for SMA wire actuators, which accounts for shakedown with and without the use of mechanical strain limiters to enable higher stress designs to maximize actuator performance. Shakedown experimental data including the effect of strain limiters along with stroke and work density contours form the basis for this new design method. For each independent mechanical strain limiter, the maximum of the individual postshakedown Austenite curves at a range of applied stress are combined into a conglomerate stabilization design curve. These curves over a set of mechanical strain limiters including the zero set provide steady-state performance prediction for SMA actuation, effectively decoupling the shakedown material performance from design variables that affect the shakedown. The use and benefits of the conglomerate stabilization curve design method are demonstrated with a common constant force actuator design example, which was validated in hardware on a heavy duty latch device. This new design method, which accounts for shakedown, supports design of SMA actuators at higher stresses with more economical use of material/power and enables the utilization of strain limiters for cost-saving in-device shakedown procedures.

A Design Method for Shape Memory Alloy Actuators Accounting for Cyclic Shakedown With Constrained Allowable Strain

2010 ◽  
Author(s):  
WonHee Kim ◽  
Brian M. Barnes ◽  
Jonathan E. Luntz ◽  
Diann E. Brei
Keyword(s):  
Design Method ◽  
Mechanical Strain ◽  
High Energy ◽  
Design Guidelines ◽  
Design Approach ◽  
High Energy Density ◽  
Interface Position ◽  
Design Variables ◽  
Graphical Design ◽  
Actuation Strain

The high energy density actuation potential of SMA wire is tempered by conservative design guidelines set to mitigate complex factors such as functional fatigue (shakedown). Shakedown causes problems of stroke loss and interface position drift between the system and the SMA wire under higher stress levels if the wire does not undergo a pre-installation shakedown procedure. Limiting actuation strain has been reported as reducing shakedown as well as increasing fatigue life. One approach to limit actuation strain is using a mechanical strain limiter which sets a fixed Martensite strain position — useful for the development of in-device shakedown procedures which eliminates time consuming pre-installation shakedown procedures. This paper presents a new graphical design approach for SMA wire actuators which accounts for shakedown with the use of mechanical strain limiters to enable higher stress designs to maximize actuator performance. Experimental data on the effect of strain limiters along with stroke and work density contours form the basis for the new graphical design method. For each independent mechanical strain limiter, the maximum of the individual post-shakedown austenite curves at a range of applied stress are combined into a conglomerate stabilization design curve. These curves over a set of mechanical strain limiters provide steady state performance prediction for SMA actuation, effectively decoupling the shakedown material performance from design variables that affect the shakedown. The use and benefits of this new design approach are demonstrated with a common constant force actuator design example. This new design approach, which accounts for shakedown, supports design of SMA actuators at higher stresses with more economical use of material/power, and enables the utilization of strain limiters for cost saving in-device shakedown procedures.

Design Framework for Multi-Section Shape Memory Alloy Axial Actuators Considering Material and Geometric Uncertainties

2020 ◽  
Author(s):  
Weilin Guan ◽  
Edwin A. Peraza Hernandez
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
High Energy ◽  
High Energy Density ◽  
Design Framework ◽  
Efficient Design ◽  
Cross Sectional ◽  
Geometric Uncertainties ◽  
In Series ◽  
The Wire

Abstract Shape memory alloys are metallic materials with the capability of performing as high energy density actuators driven by temperature control. This paper presents a design framework for shape memory alloy (SMA) axial actuators composed of multiple wire sections connected in series. The various wire sections forming the actuators can have distinct cross-sectional areas and lengths, which can be modulated to adjust the overall thermomechanical response of the actuator. The design framework aims to find the optimal cross-sectional areas and lengths of the wire sections forming the axial actuator such that its displacement vs. temperature actuation path approximates a target path. Constraints on the length-to-diameter aspect ratio and stress of the wire sections are incorporated. A reduced-order numerical model for the multi-section SMA actuators that allows for efficient design evaluations is derived and implemented. An approach to incorporate uncertainty in the geometry and material parameters of the actuators within the design framework is implemented to allow for the determination of robust actuator designs. A representative application example of the design framework is provided illustrating the benefits of using multiple wire sections in axial actuators to modulate their overall response and approximate a target displacement vs. temperature actuation path.

A Study of TiNi Shape-Memory Alloy Modified by Pulsed High-Energy Density Plasma

2002 ◽  
Vol 394-395 ◽  
pp. 149-152
Author(s):  
Xing Fang Wu ◽  
Ying Fu ◽  
Yong Han ◽  
Wen Shen Hua ◽  
Si Ze Yang
Keyword(s):  
Energy Density ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
High Energy ◽  
High Energy Density ◽  
Density Plasma

A shape memory alloy torsion actuator for static blade twist

2019 ◽  
Vol 30 (17) ◽  
pp. 2605-2626 ◽  
Author(s):  
Salvatore Ameduri ◽  
Antonio Concilio
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
System Integration ◽  
Element Model ◽  
High Energy ◽  
High Energy Density ◽  
The European Union ◽  
Structural Element ◽  
Horizon 2020

Active blade twist is an option to increase helicopter performance, for instance moving its condition from hovering to cruise. Shape memory alloys give the possibility of realizing compact devices, with high energy density. Several devices have been proposed in literature, showing limitations in terms of effectiveness and necessary room. In this article, the capability of a shape memory alloy torque tube to induce a certain twist law along the blade, while preserving its integrability within the structure, has been exploited. The study refers to a complex theoretical model, made of different specialized modules. In detail, transmitted twist action by the shape memory alloy actuators, aerodynamic effects caused by the induced geometrical change, inertial impact following the motor system integration, and system layout influence on the blade response have been taken into account. Through this model, a parametric investigation has been organized to highlight the importance of selected design variables. Tube thickness, mass, and length have been considered. Two different configurations have been initially taken into account, distinguished for the twist transmission mode and their outline. In the first hypothesis, a pre-stressed wire system converts tensile stress into a rotary action. In the second sketch, a pre-twisted solid tube connects two different stations of the blade, transmitting relative rotation. After the first trade-off, the second architecture has been selected for further analysis, focusing on its performance in terms of net transmitted twist, aerodynamic effects, while paying attention to a proper mass balance. In the chosen approach, the actuator has been installed at the torsion center. A finite element model has been used to validate the assessed analytical representation and has permitted establishing the applicability domain. Apart elastic forces, acting both in the shape memory alloys and the blade components, centrifugal forces have been taken into account by considering an increased stiffness of the reference structural element. Aerodynamic forces have been evaluated after the target configuration has been reached; helicopter trim has been considered to this purpose. The researchers aim at developing this concept by integrating the reverse action of the aerodynamic field and evaluating the importance of the actuator position along the chord. The research herein presented has been carried out within the SABRE project, project ID 723491, gratefully funded by the European Union within the Horizon 2020 program.

A finite element framework for a shape memory alloy actuated finger

2019 ◽  
Vol 30 (14) ◽  
pp. 2052-2064 ◽  
Author(s):  
Filomena Simone ◽  
Gianluca Rizzello ◽  
Stefan Seelecke
Keyword(s):  
Finite Element ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Element Model ◽  
High Energy ◽  
Good Choice ◽  
Material Behavior ◽  
Hysteretic Behavior ◽  
High Energy Density ◽  
Alloy Material

This article presents on finite element modeling of an artificial finger driven by shape memory alloy wires. These alloys appear as a promising transduction technology, due to their inherently high energy density which makes them a good choice for compact, lightweight, and silent actuator systems with many applications in the robotic field, ranging from industrial to biomedical ones. However, the complex nonlinear and hysteretic behavior of the material makes it difficult to accurately model and design shape memory alloy–actuated systems. The problem is even more challenging when shape memory alloys are used as actuators in articulated structures, adding complex kinematics and contact situations to the picture. In this article, a finite element model is developed to describe the behavior of a finger prototype, in which a bundle of shape memory alloy wires works against an extension spring. The commercially available software COMSOL is used for implementing the coupling and contact issues between the finger structure and the shape memory alloy wires. To describe the shape memory alloy material behavior, a COMSOL implementation of the Müller–Achenbach–Seelecke model is presented. By means of different experiments, it is demonstrated how the model predicts the prototype behavior in relation to different power stimuli and actuator geometries.

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.

High-Energy-Density Shape Memory Materials with Ultrahigh Strain for Reconfigurable Artificial Muscles

2021 ◽  
Author(s):  
Zheng Xu ◽  
Yujie Chen ◽  
Chi Chen ◽  
Zhen Chen ◽  
Yu Tong Guo ◽  
...  
Keyword(s):  
Energy Density ◽  
Shape Memory ◽  
High Energy ◽  
High Energy Density ◽  
Soft Robotics ◽  
Artificial Muscles ◽  
Flexible Devices ◽  
Shape Memory Materials ◽  
Ultrahigh Strain ◽  
Considerable Strain

Abstract Programmable and reconfigurable artificial muscles are highly promising and desirable for applications, including soft robotics, flexible devices, and biomedical devices. However, the combination of considerable strain and high energy...

Design of a Compliant Industrial Gripper Driven by a Bistable Shape Memory Alloy Actuator

2020 ◽  
Author(s):  
Dominik Scholtes ◽  
Stefan Seelecke ◽  
Gianluca Rizzello ◽  
Paul Motzki
Keyword(s):  
Shape Memory ◽  
High Energy ◽  
Industrial Applications ◽  
High Energy Density ◽  
Small Scale ◽  
Monitoring And Control ◽  
Actuation System ◽  
First Results ◽  
Functional Prototype ◽  
And Control

Abstract Within industrial manufacturing most processing steps are accompanied by transporting and positioning of workpieces. The active interfaces between handling system and workpiece are industrial grippers, which often are driven by pneumatics, especially in small scale areas. On the way to higher energy efficiency and digital factories, companies are looking for new actuation technologies with more sensor integration and better efficiencies. Commonly used actuators like solenoids and electric engines are in many cases too heavy and large for direct integration into the gripping system. Due to their high energy density shape memory alloys (SMA) are suited to overcome those drawbacks of conventional actuators. Additionally, they feature self-sensing abilities that lead to sensor-less monitoring and control of the actuation system. Another drawback of conventional grippers is their design, which is based on moving parts with linear guides and bearings. These parts are prone to wear, especially in abrasive environments. This can be overcome by a compliant gripper design that is based on flexure hinges and thus dispenses with joints, bearings and guides. In the presented work, the development process of a functional prototype for a compliant gripper driven by a bistable SMA actuation unit for industrial applications is outlined. The focus lies on the development of the SMA actuator, while the first design approach for the compliant gripper mechanism with solid state joints is proposed. The result is a working gripper-prototype which is mainly made of 3D-printed parts. First results of validation experiments are discussed.

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