Download or read book A New Mechanical Characterization Method for Microactuators Applied to Shape Memory Films written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a new technique for the mechanical characterization of microactuators and apply it to shape memory alloy (SMA) thin films. A test instrument was designed which utilizes a spring-loaded transducer to measure displacements with resolution of 1.5 mm and forces with resolution of 0.2 mN. Employing an out- of-plane loading method for SMA thin films, strain resolution of 30 me and stress resolution of 2.5 MPa were achieved. Four mm long, 2 [mu]m thick NiTiCu ligaments suspended across open windows were bulk micromachined for use in the out-of-plane stress and strain measurements. Static analysis showed that 63% of the applied strain was recovered while ligaments were subjected to tensile stresses of 870 MPa. This corresponds to 280 mm of actual displacement against a load of 52 mN. Fatigue analysis of the ligaments showed 33% degradation in recoverable strain (from 0.3% to 0.2%) with 2 ± 104 cycles for an initial strain of 2.8%.

Download or read book A New Mechanical Characterization Method for Thin Film Microactuators and Its Application to NiTiCi Shape Memory Alloy written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In an effort to develop a more full characterization tool of shape memory alloys, a new technique is presented for the mechanical characterization of microactuators and applied to SMA thin films. A test instrument was designed to utilize a spring-loaded transducer in measuring displacements with resolution of 1.5 pm and forces with resolution of 0.2 mN. Employing an out-of-plane loading method for freestanding SMA thin films, strain resolution of 30[mu][epsilon] and stress resolution of 2.5 MPa were achieved. This new testing method is presented against previous SMA characterization methods for purposes of comparison. Four mm long, 2[micro]m thick NiTiCu ligaments suspended across open windows were bulk micromachined for use in the out-of-plane stress and strain measurements. The fabrication process used to micromachine the ligaments is presented step-by-step, alongside methods of fabrication that failed to produce testable ligaments. Static analysis showed that 63% of the applied strain was recovered while ligaments were subjected to tensile stresses of 870 MPa. In terms of recoverable stress and recoverable strain, the ligaments achieved maximum recovery of 700 MPa and 3.0% strain. No permanent deformations were seen in any ligament during deflection measurements. Maximum actuation forces and displacements produced by the 4 mm ligaments situated on 1 cm square test chips were 56 mN and 300[micro]m, respectively. Fatigue analysis of the ligaments showed degradation in recoverable strain from 0.33% to 0.24% with 200,000 cycles, corresponding to deflections of 90[micro]m and forces of 25 mN. Cycling also produced a wavering shape memory effect late in ligament life, leading to broad inconsistencies of as much as 35% deviation from average. Unexpected phenomena like stress-induced martensitic twinning that leads to less recoverable stress and the shape memory behavior of long life devices are addressed. Finally, a model for design of microactuators using shape memory alloys is presented to illustrate how results obtained from these tests can be interpreted and applied to the creation of MEMS devices.

Download or read book A New Mechanical Characterization Method for Thin Film Microactuators and Its Application to NiTiCu Shape Memory Alloy written by Kirk Patrick Seward and published by . This book was released on 1999 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamics of Smart Structures written by Ranjan Vepa and published by John Wiley & Sons. This book was released on 2010-03-10 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamics of Smart Structures is a practical, concise and integrated text that provides an introduction to the fundamental principles of a field that has evolved over the recent years into an independent and identifiable subject area. Bringing together the concepts, techniques and systems associated with the dynamics and control of smart structures, it comprehensively reviews the differing smart materials that are employed in the development of the smart structures and covers several recent developments in the field of structural dynamics. Dynamics of Smart Structures has been developed to complement the author's new interdisciplinary programme of study at Queen Mary, University of London that includes courses on emerging and new technologies such as biomimetic robotics, smart composite structures, micro-electro-mechanical systems (MEMS) and their applications and prosthetic control systems. It includes chapters on smart materials and structures, transducers for smart structures, fundamentals of structural control, dynamics of continuous structures, dynamics of plates and plate-like structures, dynamics of piezoelectric media, mechanics of electro-actuated composite structures, dynamics of thermo-elastic media: shape memory alloys, and controller designs for flexible structures.

Download or read book Shape Memory Microactuators written by Manfred Kohl and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: Overview of recent achievements, describing the microactuator development of microvalves and liner actuators comprehensively from concept through prototype. Further key aspects included are three-dimensional models for handling complex SMA actuator geometries and coupled simulation routines that take multifunctional properties into account. Mechanical and thermal optimization criteria are introduced for actuator design, allowing an optimum use of the shape memory effect. It is shown that some of the prototypes presented, e.g. SMA microgrippers, already outperform conventional components.

Download or read book Fabrication Characterization and Implementation of Actuators Based on Thin Shape Memory Alloy Films written by Meni Kabla and published by . This book was released on 2015 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Volume mediated Capacitive Transducer and Wireless Sensor with Integrated Hydrogel for Chemical Sensing written by Zoe Antoinette Strong and published by . This book was released on 2006 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermomechanical Training and Characterization of Shape Memory Alloy Axial Actuators written by Marcus Patrick Becker and published by . This book was released on 2010 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although considerable work has been performed to understand the key mechanisms of Shape Memory Alloy (SMA) behavior, little of this work follows a standard testing protocol, quantifies a conditioning methodology, or develops data appropriate for design of SMA actuators. One major issue that limits the ability of the material from being used directly as an actuator is the large, non-recoverable strains likely to accrue in the material during each training cycle, mechanical or thermal. When mechanical or thermal cycling is performed, a hysteresis curve develops and reaches a steady state strain recovery response. At the point where permanent plastic strain stops growing, or saturates, the SMA has been successfully trained. The focus of this work is oriented toward SMAs in general, but all testing and experimentation was carried out on Nickel-Titanium (NiTi) alloys. The experimentation and testing was performed on a combination of 4 different sizes and 3 different NiTi alloy compositions. Thermomechanical testing was performed to determine critical values to describe the stress-temperature phase space of the materials and parameters to model the applied stress and transformation strain relationship. All material size and alloy combinations were tested in the as-received, or as-machined, and fully annealed state. The results of the training and actuation strain characterization process developed in this work shows that the samples that experienced Transformation Induced Plasticity (TRIP), greater than 2% during the training process and exhibit Two-Way Shape Memory (TWSM) after being fully trained, share a very similar applied stress versus transformation strain curve. This curve is modeled by the Back Stress formulation derived from the Gibbs Free Energy constitutive model by Bo & Lagoudas. The design space created by the Back Stress formulation, recrystallization temperature, and training stress allows SMA materials to be characterized and implemented as stable 1-D actuators. This research formalized a thermomechanical training and characterization method for uniaxial SMA actuators by addressing the interaction between processing, recoverable and non-recoverable deformation. Using various sizes and NiTi alloy combinations, this research develops and evaluates a method to train and characterize a diverse range of SMAs through a set of thermomechanical and physical property measurements.

Download or read book Fabrication and Characterization of Nanoscale Shape Memory Alloy MEMS Actuators written by Cory R. Knick and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The miniaturization of engineering devices has created interest in new actuation methods capable of large displacements and high frequency responses. Shape memory alloy (SMA) thin films have exhibited one of the highest power densities of any material used in these actuation schemes and can thermally recovery strains of up to 10%. Homogenous SMA films can experience reversible shape memory effect, but without some sort of physical biasing mechanism, the effect is only one-way. SMA films mated in a multi-layer stack have the appealing feature of an intrinsic two-way shape memory effect (SME). In this work, we developed a near-equiatomic NiTi magnetron co-sputtering process and characterized shape memory effects. We mated these SMA films in several ,Äúbimorph,Äù configurations to induce out of plane curvature in the low-temperature Martensite phase. We quantify the curvature radius vs. temperature on MEMS device structures to elucidate a relationship between residual stress, recovery stress, radius of curvature, and degree of unfolding. We fabricated and tested laser-irradiated and joule heated SMA MEMS actuators to enable rapid actuation of NiTi MEMS devices, demonstrating some of the lowest powers (5,Äì15 mW) and operating frequencies (1,Äì3 kHz) ever reported for SMA or other thermal actuators.

Download or read book Thin Film Shape Memory Alloys written by Shuichi Miyazaki and published by Cambridge University Press. This book was released on 2009-09-03 with total page 487 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first dedicated book describing the properties, preparation, characterization and device applications of TiNi-based shape memory alloys.

Download or read book Microelectromechanical Systems written by and published by . This book was released on 1996 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1044 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Engineering Aspects of Shape Memory Alloys written by T W Duerig and published by Butterworth-Heinemann. This book was released on 2013-10-22 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Engineering Aspects of Shape Memory Alloys provides an understanding of shape memory by defining terms, properties, and applications. It includes tutorials, overviews, and specific design examples—all written with the intention of minimizing the science and maximizing the engineering aspects. Although the individual chapters have been written by many different authors, each one of the best in their fields, the overall tone and intent of the book is not that of a proceedings, but that of a textbook. The book consists of five parts. Part I deals with the mechanism of shape memory and the alloys that exhibit the effect. It also defines many essential terms that will be used in later parts. Part II deals primarily with constrained recovery, but to some extent with free recovery. There is an introductory paper which defines terms and principles, then several specific examples of products based on constrained recovery. Both Parts III and IV deal with actuators. Part III introduces engineering principles while Part IV presents several of the specific examples. Finally, Part V deals with superelasticity, with an introductory paper and then several specific examples of product engineering.

Download or read book Polyurethane Shape Memory Polymers written by W.M. Huang and published by CRC Press. This book was released on 2011-09-08 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shape memory polymers (SMPs) are some of the most important and valuable engineering materials developed in the last 25 years. These fascinating materials demonstrate remarkably versatile properties-including capacity for actuation and stimulus responsiveness-that are enabling technologists to develop applications used to explore everything from th

Download or read book Shape Memory Alloys for Biomedical Applications written by T Yoneyama and published by Elsevier. This book was released on 2008-11-21 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shape memory alloys are suitable for a wide range of biomedical applications, such as dentistry, bone repair and cardiovascular stents. Shape memory alloys for biomedical applications provides a comprehensive review of the use of shape memory alloys in these and other areas of medicine. Part one discusses fundamental issues with chapters on such topics as mechanical properties, fabrication of materials, the shape memory effect, superelasticity, surface modification and biocompatibility. Part two covers applications of shape memory alloys in areas such as stents and orthodontic devices as well as other applications in the medical and dental fields. With its distinguished editors and international team of contributors, Shape memory alloys for biomedical applications is an essential reference for materials scientists and engineers working in the medical devices industry and in academia. A comprehensive review of shape memory metals and devices for medical applications Discusses materials, mechanical properties, surface modification and biocompatibility Chapters review medical and dental devices using shape memory metals, including stents and orthodontic devices

Download or read book Viscoelastic Solids 1998 written by Roderic S. Lakes and published by CRC Press. This book was released on 2017-11-22 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: Viscoelastic Solids covers the mathematical theory of viscoelasticity and physical insights, causal mechanisms, and practical applications. The book: presents a development of the theory, addressing both transient and dynamic aspects as well as emphasizing linear viscoelasticity synthesizes the structure of the theory with the aim of developing physical insight illustrates the methods for the solution of stress analysis problems in viscoelastic objects explores experimental methods for the characterization of viscoelastic materials describes the phenomenology of viscoelasticity in a variety of materials, including polymers, metals, high damping alloys, rock, piezoelectric materials, cellular solids, dense composite materials, and biological materials analyzes high damping and extremely low damping provides the theory of viscoelastic composite materials, including examples of various types of structure and the relationships between structure and mechanical properties contains examples on the use of viscoelastic materials in preventing and alleviating human suffering Viscoelastic Solids also demonstrates the use of viscoelasticity for diverse applications, such as earplugs, gaskets, computer disks, satellite stability, medical diagnosis, injury prevention, vibration abatement, tire performance, sports, spacecraft explosions, and music.

Download or read book Microelectromechanical Systems written by Committee on Advanced Materials and Fabrication Methods for Microelectromechanical Systems and published by National Academies Press. This book was released on 1997-12-15 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microelectromenchanical systems (MEMS) is a revolutionary field that adapts for new uses a technology already optimized to accomplish a specific set of objectives. The silicon-based integrated circuits process is so highly refined it can produce millions of electrical elements on a single chip and define their critical dimensions to tolerances of 100-billionths of a meter. The MEMS revolution harnesses the integrated circuitry know-how to build working microsystems from micromechanical and microelectronic elements. MEMS is a multidisciplinary field involving challenges and opportunites for electrical, mechanical, chemical, and biomedical engineering as well as physics, biology, and chemistry. As MEMS begin to permeate more and more industrial procedures, society as a whole will be strongly affected because MEMS provide a new design technology that could rival--perhaps surpass--the societal impact of integrated circuits.