Download or read book Thermal Modeling of Shape Memory Alloy Wire Actuators for Automotive Applications written by Huilong Ma and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Shape Memory Alloy Actuators written by Mohammad H. Elahinia and published by John Wiley & Sons. This book was released on 2016-01-19 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a systematic approach to realizing NiTi shape memory alloy actuation, and is aimed at science and engineering students who would like to develop a better understanding of the behaviors of SMAs, and learn to design, simulate, control, and fabricate these actuators in a systematic approach. Several innovative biomedical applications of SMAs are discussed. These include orthopedic, rehabilitation, assistive, cardiovascular, and surgery devices and tools. To this end unique actuation mechanisms are discussed. These include antagonistic bi-stable shape memory-superelastic actuation, shape memory spring actuation, and multi axial tension-torsion actuation. These actuation mechanisms open new possibilities for creating adaptive structures and biomedical devices by using SMAs.

Download or read book Design of Shape Memory Alloy SMA Actuators written by Ashwin Rao and published by Springer. This book was released on 2015-05-08 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: This short monograph presents an analysis and design methodology for shape memory alloy (SMA) components such as wires, beams, and springs for different applications. The solid-solid, diffusionless phase transformations in thermally responsive SMA allows them to demonstrate unique characteristics like superelasticity and shape memory effects. The combined sensing and actuating capabilities of such materials allows them to provide a system level response by combining multiple functions in a single material system. In SMA, the combined mechanical and thermal loading effects influence the functionality of such materials. The aim of this book is to make the analysis of these materials accessible to designers by developing a "strength of materials" approach to the analysis and design of such SMA components inspired from their various applications with a review of various factors influencing the design process for such materials.

Download or read book Shape Memory Alloys Handbook written by Christian Lexcellent and published by John Wiley & Sons. This book was released on 2013-04-08 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this book is to understand and describe the martensitic phase transformation and the process of martensite platelet reorientation. These two key elements enable the author to introduce the main features associated with the behavior of shape-memory alloys (SMAs), i.e. the one-way shape-memory effect, pseudo-elasticity, training and recovery. Attention is paid in particular to the thermodynamical frame for solid materials modeling at the macroscopic scale and its applications, as well as to the particular use of such alloys – the simplified calculations for the bending of bars and their torsion. Other chapters are devoted to key topics such as the use of the “crystallographical theory of martensite” for SMA modeling, phenomenological and statistical investigations of SMAs, magneto-thermo-mechanical behavior of magnetic SMAs and the fracture mechanics of SMAs. Case studies are provided on the dimensioning of SMA elements offering the reader an additional useful framework on the subject. Contents 1. Some General Points about SMAs. 2. The World of Shape-memory Alloys. 3. Martensitic Transformation. 4. Thermodynamic Framework for the Modeling of Solid Materials. 5. Use of the “CTM” to Model SMAs. 6. Phenomenological and Statistical Approaches for SMAs. 7. Macroscopic Models with Internal Variables. 8. Design of SMA Elements: Case Studies. 9. Behavior of Magnetic SMAs. 10. Fracture Mechanics of SMAs. 11. General Conclusion. Appendix 1. Intrinsic Properties of Rotation Matrices. Appendix 2. “Twinning Equation” Demonstration. Appendix 3. Calculation of the Parameters a, n and Q from the “Twinning” Equation. Appendix 4. “Twinned” Austenite/Martensite Equation. About the Authors Christian Lexcellent is Emeritus Professor at the École National Supérieure de Mécanique et des Microtechniques de Besançon and a researcher in the Department of Applied Mechanics at FEMTO-ST in France. He is a specialist in the mechanics of materials and phase transition and has taught in the subjects of mechanics of continuum media and shape memory alloys. He is also a member of the International Committee of ESOMAT.

Download or read book Issues in the Design of Shape Memory Alloy Actuators written by Stéphane Lederlé and published by . This book was released on 2002 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Shape Memory Alloy Actuators written by Burcu Dönmez and published by . This book was released on 2011-11 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fabrication and Model Based Position Estimation of Novel Laser Processed Shape Memory Alloy Actuator with an Embedded Strain Gauge Sensor written by Nima Zamani and published by . This book was released on 2017 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shape Memory Alloys have sparked great amount of interest in the eld of actuation over the past decades. Until now, sensorless position estimation of SMA actuators under dynamic unknown applied stresses has not been feasible due to the complexity of the system and the number of unknown parameters which the proposed extra information obtained from the embedded sensor solves. In this thesis, a novel laser processed NiTi Shape Memory Alloy (SMA) actuator is proposed containing two di erent material compositions in one monolithic piece of actuator wire. Each of these compositions behaves di erently at room temperature, one exhibits a shape memory e ect (SME) for actuation, and the other is pseudo-elastic (PE) which is used to enable an embedded sensor. Fabrication of the wire included laser processing, heat-treatment, and cold-working procedures. The actuator wire was subsequently trained to stabilize its properties using iso-stress thermal cycling. Additionally, a novel model-based sensorless position estimation algorithm is presented. Proposed model can estimate the position of the actuator under varying applied stresses with an approximate accuracy of 95% only using dual resistance measurements across the two di erent material compositions. The proposed actuator has signi cant application in robotics, wearables, haptics, automotive, and any other application which the mechanical load is not known in advance. Two simple position and force controller schemes using the proposed dual-resistance measurement position (and force) estimation are discussed and the control results presented. The proposed position estimation algorithm is used for the feedback-signal of a simple PID position and force controller scheme. Moreover, another novel sensorless position estimation of SMA actuator wires are presented using the power measurement of the standing wave cause by the re ection of a high-frequency signal at an un-terminated end.

Download or read book Shape Memory Alloy Engineering written by Antonio Concilio and published by Elsevier. This book was released on 2014-09-25 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shape Memory Alloy Engineering introduces materials, mechanical, and aerospace engineers to shape memory alloys (SMAs), providing a unique perspective that combines fundamental theory with new approaches to design and modeling of actual SMAs as compact and inexpensive actuators for use in aerospace and other applications. With this book readers will gain an understanding of the intrinsic properties of SMAs and their characteristic state diagrams, allowing them to design innovative compact actuation systems for applications from aerospace and aeronautics to ships, cars, and trucks. The book realistically discusses both the potential of these fascinating materials as well as their limitations in everyday life, and how to overcome some of those limitations in order to achieve proper design of useful SMA mechanisms. Discusses material characterization processes and results for a number of newer SMAs Incorporates numerical (FE) simulation and integration procedures into commercial codes (Msc/Nastran, Abaqus, and others) Provides detailed examples on design procedures and optimization of SMA-based actuation systems for real cases, from specs to verification lab tests on physical demonstrators One of the few SMA books to include design and set-up of demonstrator characterization tests and correlation with numerical models

Download or read book Development Characterization and Application of Ni19 5Ti50 5Pd25Pt5 High temperature Shape Memory Alloy Helical Actuators written by Aaron P. Stebner and published by . This book was released on 2007 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Shape memory alloys (SMAs) have been used as actuators in many different industries since the discovery of the shape memory effect. These include, but are not limited to, applications in the automobile industry, medical devices, commercial plumbing, and robotics. The use of SMAs as actuation devices in aeronautics has been limited due to the temperature constraints of commercially available materials. Consequently, work is being done at NASA's Glenn Research Center to develop new SMAs capable of being used in high temperature environments. One of the more promising high-temperature shape memory alloys (HTSMAs) is Ni19.5Ti50.5Pd25Pt5. Recent work has shown that this material is capable of being used in operating environments of up to 250°C. This material has also been shown to have very useful actuation capabilities, demonstrating repeatable strain recoveries up to 2.5% in the presence of an externally applied load. Based on these findings, further work has been initiated to explore potential applications and alternative forms of this alloy, such as springs. Thus, characterization of Ni19.5Ti50.5Pd25Pt5 springs, including their mechanical response (e.g. stroke capabilities, load carrying capabilities, and work outputs) and how variations in this response correlate to changes in geometric parameters (e.g. wire diameter, coil diameter, wire-to-coil diameter ratio, and number of coils) are discussed. The effects of loading history, or training, on spring behavior were also investigated. A comparison of the springs with wire actuators is made and the benefits of using one actuator form as opposed to the other discussed. These findings are used to discuss design considerations for a surge-control mechanism used in the centrifugal compressor of a T-700 helicopter engine. The mechanical response observed during testing is then compared with responses predicted using current SMA spring design methodology are discussed in terms of future work needed to develop a model for HTSMA springs that can accurately guide engineering design."--Abstract.

Download or read book Shape Memory Alloys written by Dimitris C. Lagoudas and published by Springer Science & Business Media. This book was released on 2008-06-05 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a working knowledge of the modeling and engineering applications of shape memory alloys (SMAs), beginning with a rigorous introduction to continuum mechanics and continuum thermodynamics as they relate to the development of SMA modeling.Modern SMAs can recover from large amounts of bending and deformation, and millions of repetitions within recoverable ranges. SMAs are used in the medical industry to create stents, in the dental industry to create dental and orthodontic archwires, and in the aerospace industry to create fluid fittings. The text presents a unified approach to the constitutive modeling of SMAs, including modeling of magnetic and high temperature SMAs.

Download or read book Shape Memory Alloys written by Farzad Ebrahimi and published by BoD – Books on Demand. This book was released on 2017-09-20 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a result of contributions of experts from international scientific community working in different aspects of shape memory alloys (SMAs) and reports on the state-of-the-art research and development findings on this topic through original and innovative research studies. Through its five chapters, the reader will have access to works related to ferromagnetic SMAs, while it introduces some specific applications like development of faster SMA actuators and application of nanostructural SMAs in medical devices. The book contains up-to-date publications of leading experts, and the edition is intended to furnish valuable recent information to the professionals involved in shape memory alloys analysis and applications. The text is addressed not only to researchers but also to professional engineers, students, and other experts in a variety of disciplines, both academic and industrial, seeking to gain a better understanding of what has been done in the field recently and what kind of open problems are in this area.

Download or read book Alloys and Intermetallic Compounds written by Cristina Artini and published by CRC Press. This book was released on 2017-07-12 with total page 267 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the role of modeling in the design of alloys and intermetallic compounds. It includes an introduction to the most important and most used modeling techniques, such as CALPHAD and ab-initio methods, as well as a section devoted to the latest developments in applications of alloys. The book emphasizes the correlation between modeling and technological developments while discussing topics such as wettability of Ultra High Temperature Ceramics by metals, active brazing of diamonds to metals in cutting tools, surface issues in medicine, novel Fe-based superconductors, metallic glasses, high entropy alloys, and thermoelectric materials.

Download or read book Segmented Binary Control of Shape Memory Actuator Systems written by Brian A. Selden and published by . This book was released on 2005 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new approach to the design and control of shape memory alloy (SMA) actuators is presented. SMA wires are divided into many segments and their thermal states are controlled individually as a group of finite state machines. Instead of driving a current to the entire SMA wire and controlling the wire length based on the analogue strain-temperature characteristics, the new method controls the binary state (hot or cold) of individual segments and thereby the total displacement is proportional to the length of the heated segments, i.e. austenite phase. Although the thermo-mechanical properties of SMA are highly nonlinear and uncertain with a prominent hysteresis, Segmented Binary Control is robust and stable, providing characteristics similar to a stepping motor. However, the heating and cooling of each segment to its bi-stable states entail longer time and larger energy for transition. An efficient method for improving speed of response and power consumption is developed by exploiting the inherent hysteresis of SMA. Instead of keeping the extreme temperatures continuously, the temperatures return to intermediate "hold" temperatures closer to room temperature but sufficient to keep constant phase. Coordination of the multitude of segments having independent thermal states allows for faster response with little latency time even for thick SMA wires. Based on stress dependent thermo-mechanical characteristics, the hold temperature satisfying a given Stress Margin is obtained. The new control method is implemented using the Peltier effect thermoelectric devices for selective segment-by-segment heating and cooling. Experiments demonstrate effectiveness of the proposed method.

Download or read book Dynamic Modeling and Control System Design for Shape Memory Alloy Actuators written by In Seon Kim and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Adaptive Inverse Modeling of a Shape Memory Alloy Wire Actuator and Tracking Control with the Model written by Bong Su Koh and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: It is well known that the Preisach model is useful to approximate the effect of hysteresis behavior in smart materials, such as piezoactuators and Shape Memory Alloy(SMA) wire actuators. For tracking control, many researchers estimate a Preisach model and then compute its inverse model for hysteresis compensation. However, the inverse of its hysteresis behavior also shows hysteresis behavior. From this idea, the inverse model with Kransnoselskii-Pokrovskii(KP) model, a developed version of Preisach model, can be used directly for SMA position control and avoid the inverse operation. Also, we propose another method for the tracking control by approximating the inverse model using an orthogonal polynomial network. To estimate and update the weight parameters in both inverse models, a gradient-based learning algorithm is used. Finally, for the SMA position control, PID controller, adaptive controllers with KP model and adaptive nonlinear inverse model controller are compared experimentally.

Download or read book Papers Re Melbourne University Press written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Improving Residual Stress and Heat Transfer in Shape Memory Alloy Actuation written by Lawrence Bradley and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shape memory alloys (SMA) are a class of functional materials that are best known for their very high strength to weight ratio as actuators. This is due to temperature dependent phase transformation, which allows 4-6% strain. When heated, they contract in length -- thereby producing very large actuation force. Despite their unique properties, the applications of shape memory alloys as actuators are limited by (a) slow actuation rate that is critically influenced by cooling time and (b) residual stress in the material that reduce the amount of the recoverable strain. In the first part of this research, we propose a new actuation mode where we integrate conduction mode heat transfer in the SMA wire, without any additional element that increases size of weight of the actuators. This is motivated by the observation that the it is not possible to improve natural convective heat transfer for a given specimen cross-section and that conduction mode is faster than convection. We propose a 'segmented actuation' where instead of heating the entire length of the wire, we piecewise segment it and perform controlled heating. This allows the unheated segment (neighboring two heated ones) act as a temporary heatsink that receives heat by conduction. Using a controller along with segmented heating of the alloy, we demonstrate that the actuation rate can be improved three-fold, without any change in the shape memory properties. However, the segmented approach essentially costs some recoverable strain. In the second part of this research, we focus on the residual stress in the SMA wire, which is difficult to avoid because the wires are manufacturing by drawing process. We propose a unique annealing process that works at significantly lower temperature (