Academic literature on the topic 'Mechanical engineering. Shape memory alloys. High pressure (Technology)'
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Journal articles on the topic "Mechanical engineering. Shape memory alloys. High pressure (Technology)"
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Gurau, Gheorghe, Carmela Gurau, Mihaela Banu, and Leandru Gheorghe Bujoreanu. "Microstructural Evolution in Ultrafine Grained FeMnSiCr Shape Memory Alloy Modules." Advanced Materials Research 1143 (February 2017): 214–20. http://dx.doi.org/10.4028/www.scientific.net/amr.1143.214.
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High speed high pressure torsion (HSHPT) processing technology, engineered to achieving (ultra) fine bulk metallic structure under high pressure (~ GPa) and torsion by applying supplementary elevated rotation speed of superior anvil. Coned-disk spring shape modules were processed from an as cast Fe-28Mn-6Si-5Cr (mass %) shape memory alloy (SMA). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies revealed that the structure of modules became submicron as an effect of HSHPT processing. After severe plastic deformation, a grain size gradient was obtained along the truncated cone generator, increasing from inner to outer areas, due to different deformation degrees in these zones. The mechanical and shape memory properties was performed in order to relate the structural changes caused by severe plastic deformation.
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Aleksei, Grunin, Maksimova Ksenia, and Goikhman Aleksander. "The features of Ni2MnIn polycrystalline Heusler alloy thin films formation by pulsed laser deposition." Open Engineering 11, no. 1 (December 20, 2020): 227–32. http://dx.doi.org/10.1515/eng-2021-0019.
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AbstractThe Ni-Mn-In-based Heusler alloys belong to the most studied intermetallic compounds due to a variety of physical effects inherent to them, including the shape memory and magnetocaloric effect, field-induced structural phase transition, and others. All of these properties are strongly depend on element concentrations, uniformity, and purity of the structure. Therefore, rather strict requirements are imposed on the synthesis technology of such samples.We report the dependencies of Ni-Mn-In polycrystalline thin film composition on growth parameters. It was shown that the composition mismatch between sample and target caused by the resputtering of the sample material with high-energy particles of the ablation plume, and the different ablation yields of elements from the target. The main deposition parameters demonstrated (Ar growth pressure, laser energies, substrate temperature and annealing, target-to-sample distance) for the co-deposition process to obtain the Ni-Mn-In Heusler alloy polycrystalline thin films with the martensitic transition.
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Shuitcev, A., D. V. Gunderov, B. Sun, L. Li, R. Z. Valiev, and Y. X. Tong. "Nanostructured Ti29.7Ni50.3Hf20 high temperature shape memory alloy processed by high-pressure torsion." Journal of Materials Science & Technology 52 (September 2020): 218–25. http://dx.doi.org/10.1016/j.jmst.2020.01.065.
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Gunderov, Dmitriy, Alexandr Lukyanov, Egor Prokofiev, Anna Churakova, Vladimir Pushin, Sergey Prokoshkin, Vladimir Stolyarov, and Ruslan Valiev. "Microstructure and Mechanical Properties of the SPD-Processed TiNi Alloys." Materials Science Forum 738-739 (January 2013): 486–90. http://dx.doi.org/10.4028/www.scientific.net/msf.738-739.486.
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The article represents results of influence of different severe plastic deformation (SPD) techniques on TiNi alloys. It is demonstrated that strength and shape memory effect (SME) of TiNi can be significantly enhanced due to formation of ultrafine-grained (UFG) and nanocrystalline (NC) structures by SPD. Influence of equal channel angular pressing (ECAP), high pressure torsion (HPT), multi-step SPD deformations (ECAP plus cold rolling) on structure, mechanical and functional properties of TiNi alloys is considered. There are represented first results of influence of equal channel angular pressure-Conform (ECAP-C) on TiNi alloys, which is a perspective technology for industrial fabrication of UFG metals and alloys.
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Gerstein, Gregory, Victor A. L'vov, Anna Kosogor, and Hans J. Maier. "Internal pressure as a key thermodynamic factor to obtain high-temperature superelasticity of shape memory alloys." Materials Letters 210 (January 2018): 252–54. http://dx.doi.org/10.1016/j.matlet.2017.09.034.
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Salowitz, Nathan, Ameralys Correa, Trishika Santebennur, Afsaneh Dorri Moghadam, Xiaojun Yan, and Pradeep Rohatgi. "Mechanics of nickel–titanium shape memory alloys undergoing partially constrained recovery for self-healing materials." Journal of Intelligent Material Systems and Structures 29, no. 15 (June 18, 2018): 3025–36. http://dx.doi.org/10.1177/1045389x18781260.
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Engineered self-healing materials seek to create an innate ability for materials to restore mechanical strength after incurring damage, much like biological organisms. This technology will enable the design of structures that can withstand their everyday use without damage but also recover from damage due to an overload incident. One of the primary mechanisms for self-healing is the incorporation of shape memory fibers in a composite type structure. Upon activation, these shape memory fibers can restore geometric changes caused by damage and close fractures. To date, shape memory–based self-healing, without bonding agents, has been limited to geometric restoration without creating a capability to withstand externally applied tensile loads due to the way the shape memory material has been integrated into the composite. Some form of bonding has been necessary for self-healing materials to resist an externally applied load after healing. This article presents results of new study into using a form of constrained recovery of nickel–titanium shape memory alloys in self-healing materials to create residual compressive loads across fractures in the low temperature martensitic state. Analysis is presented relating internal loads in self-healing materials, potentially generated by shape memory alloys, to the capability to resist externally applied loads. Supporting properties were experimentally characterized in nickel–titanium shape memory alloy wires. Finally, self-healing samples were synthesized and tested demonstrating the ability to resist externally applies loads without bonding. This study provides a new useful characterization of nickel–titanium applicable to self-healing structures and opens the door to new forms of healing like incorporation of pressure-based bonding.
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Wheeler, Robert W., Othmane Benafan, Frederick T. Calkins, Xiujie Gao, Zahra Ghanbari, Garrison Hommer, Dimitris Lagoudas, et al. "Engineering design tools for shape memory alloy actuators: CASMART collaborative best practices and case studies." Journal of Intelligent Material Systems and Structures 30, no. 18-19 (September 22, 2019): 2808–30. http://dx.doi.org/10.1177/1045389x19873390.
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One of the primary goals of the Consortium for the Advancement of Shape Memory Alloy Research and Technology is to enable the design of revolutionary applications based on shape memory alloy technology. To advance this goal and reduce the development time and required experience for the fabrication of shape memory alloy actuation systems, several modeling tools were developed for common actuator types and are discussed along with case studies, which highlight their capabilities and limitations. Shape memory alloys have many potential applications as reliable, lightweight, solid-state actuators given their ability to sustain high stresses and recover large deformations. In this article, modeling frameworks are developed for three common actuator designs: wires, lightweight, low-profile, and easily implemented; coiled springs, offering actuation strokes upward of 200% at reduced mechanical loads; and torque tubes, which can provide large actuation torques in small volumes and repeatable low-load actuation. Although the design and integration of a shape memory alloy–based actuation system requires application- and environment-specific engineering considerations, common modeling tools can significantly reduce the investment required for actuation system development and provide valuable engineering insight. This analysis presents a collection of Consortium for the Advancement of Shape Memory Alloy Research and Technology collaborative best practices to allow readers to utilize the available design tools and understand their modeling principles.
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Simone, Filomena, Gianluca Rizzello, and Stefan Seelecke. "A finite element framework for a shape memory alloy actuated finger." Journal of Intelligent Material Systems and Structures 30, no. 14 (July 5, 2019): 2052–64. http://dx.doi.org/10.1177/1045389x19861787.
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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.
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Achiţei, Dragoş Cristian, Petrică Vizureanu, Alina Adriana Minea, Mohd Mustafa Al Bakri Abdullah, Mirabela Georgiana Minciună, and Andrei Victor Sandu. "Improvement of Properties of Aluminum Bronze CuAl7Mn3 by Heat Treatments." Applied Mechanics and Materials 657 (October 2014): 412–16. http://dx.doi.org/10.4028/www.scientific.net/amm.657.412.
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Top domains of technology, such as aerospace, nuclear technology, electrical engineering, electronics, energy, require materials and alloys with special properties: superconductivity, superplasticity, high resistance to corrosion, shape memory, exceptional mechanical strength, magnetism, and resistivity. Aluminum bronzes are bronze with very good mechanical and chemical properties, which are factory profiles, strips, bearings, gears, valves, parts and fittings for chemical and food industry, gears, water pump housings, mainly parts corrosion resistant in aggressive environments.
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Schmelter, Tobias, Benedict Theren, Sebastian Fuchs, and Bernd Kuhlenkötter. "Development of an Actuator for Translatory Movement by Means of a Detented Switching Shaft Based on a Shape Memory Alloy Wire for Repeatable Mechanical Positioning." Crystals 11, no. 2 (February 6, 2021): 163. http://dx.doi.org/10.3390/cryst11020163.
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Actuators based on the shape memory effect have recently become more and more economically important due to the many advantages of shape memory alloys (SMAs), such as their high energy density. SMAs are usually used to control the end/maximum positions, thus the actuators always move between two positions. The repeatable control of intermediate positions has so far proven difficult, because in most cases, external sensors are necessary to determine the length of the SMA element. Additionally control strategies for SMA actuators are rather complex due to the non-linear behavior of this material. The SMA actuator presented here is able to control intermediate positions with repeatable accuracy without the need of a separate control technology. The integrated control unit is based on a mechanical principle using a shaft with a circumference groove. This groove has a height profile that turns the shafts rotation, generated by the SMA, into a translational movement. Therefore, the SMA wire generates a partial stroke at each complete activation, turning the shaft partially. With several activation cycles in a row, the stroke adds up until reaching the maximum. A further activation cycle of the wire resets the actuators stroke to its initial position. Each part of the stroke can, thereby, be controlled precisely and repeatedly within the scope of each complete cycle of the actuator. Based on an integrated ratchet, each stroke of the actuator can hold energy free.
Dissertations / Theses on the topic "Mechanical engineering. Shape memory alloys. High pressure (Technology)"
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Xie, Oliver Hongchun Zhou Jack. "Design, simulation and experimental study of shape memory alloy and micro-motor activated high pressure optical cell for bio-physical studies /." Philadelphia, Pa. : Drexel University, 2007. http://hdl.handle.net/1860/2525.
Full textConference papers on the topic "Mechanical engineering. Shape memory alloys. High pressure (Technology)"
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Wheeler, Robert W., Othmane Benafan, Xiujie Gao, Frederick T. Calkins, Zahra Ghanbari, Garrison Hommer, Dimitris Lagoudas, et al. "Engineering Design Tools for Shape Memory Alloy Actuators: CASMART Collaborative Best Practices and Case Studies." In ASME 2016 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/smasis2016-9183.
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The primary goal of the Consortium for the Advancement of Shape Memory Alloy Research and Technology (CASMART) is to enable the design of revolutionary applications based on shape memory alloy (SMA) technology. In order to help realize this goal and reduce the development time and required experience for the fabrication of SMA actuation systems, several modeling tools have been developed for common actuator types and are discussed herein along with case studies, which highlight the capabilities and limitations of these tools. Due to their ability to sustain high stresses and recover large deformations, SMAs have many potential applications as reliable, lightweight, solid-state actuators. Their advantage over classical actuators can also be further improved when the actuator geometry is modified to fit the specific application. In this paper, three common actuator designs are studied: wires, which are lightweight, low-profile, and easily implemented; springs, which offer actuation strokes upwards of 200% at reduced mechanical loads; and torque tubes, which can provide large actuation forces in small volumes and develop a repeatable zero-load actuation response (known as the two-way shape memory effect). The modeling frameworks, which have been implemented in the design tools, are developed for each of these frequently used SMA actuator types. In order to demonstrate the versatility and flexibility of the presented design tools, as well as validate their modeling framework, several design challenges were completed. These case studies include the design and development of an active hinge for the deployment of a solar array or foldable space structure, an adaptive solar array deployment and positioning system, a passive air temperature controller for the regulation of flow temperatures inside of a jet engine, and a redesign of the Corvette active hatch, which allows for pressure equalization of the car interior. For each of the presented case studies, a prototype or proof-of-concept was fabricated and the experimental results and lessons learned are discussed. This analysis presents a collection of CASMART collaborative best practices in order to allow readers to utilize the available design tools and understand their modeling principles. These design tools, which are based on engineering models, can provide first-order optimal designs and are a basic and efficient method for either demonstrating design feasibility or refining design parameters. Although the design and integration of an SMA-based actuation system always requires application- and environment-specific engineering considerations, common modeling tools can significantly reduce the investment required for actuation system development and provide valuable engineering insight.
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Xin, Rong, Shuo Yang, and GuiFu Dong. "Effect of Co Addition on Martensitic Transformation, Mechanical And Magnetic Properties of Polycrystalline Ga42.5Mn29Ni28.5 High Temperature Ferromagnetic Shape Memory Alloys." In The Joint Conferences of 2015 International Conference on Computer Science and Engineering Technology (CSET2015) and 2015 International Conference on Medical Science and Biological Engineering (MSBE2015). WORLD SCIENTIFIC, 2015. http://dx.doi.org/10.1142/9789814651011_0097.
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Predki, Wolfgang, and Bjo¨rn Bauer. "Safety Clutches With Nickel-Titanium Shape Memory Alloys." In ASME 2009 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2009. http://dx.doi.org/10.1115/smasis2009-1262.
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The ability of Shape Memory Alloys (SMA) to remind two different macroscopic shapes and to alter between these shapes by changing their temperature, leads to innovative approaches within drive technology. Especially Nickel-Titanium (NiTi) Shape Memory Alloys offer high actuating forces and adjustment travel in combination with high cycle stability. The shape memory effect is based on the transformation between martensitic and austenitic microstructure depending on the temperature of the actuators. The transformation temperatures in the range of 20°C to 100°C make NiTi SMA attractive for engineering applications. This paper investigates the technical use of NiTi SMA as actuators within a safety clutch. Safety clutches serve in power trains as torque limiting elements with the aim to prevent destruction of the working machine or the motor. Based on the concept of a friction clutch the conceptual design of the NiTi safety clutch is developed and followed by the design and manufacturing of a prototype. The activation of the NiTi actuators occurs as a result of the frictional heat at the friction pads when the torque limit is exceeded and the clutch slips. The actuators transform from martensitic to austenitic condition. Their stiffness increases so that the actuators are able to open the clutch. This leads to a complete collapse of the torque. During the cooling phase the transformation from austenite to martensite occurs and the NiTi actuators are deformed again. The friction pads are clamped with their original force and the clutch is able to transmit the demanded torque. The mechanical dimensioning of the actuator system is figured out as well as the measurement results of the analysis on the testing bench. The variation of the input parameters like torque and speed and the variation of the actuator system itself show possibilities and frontiers of this technology.
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Wang, Gang, Norman Wereley, Liyang Dai, Manfred Wuttig, Raffi Sahul, and Vasil Tasovski. "Rapid Consolidation of Hf Doped NiTi for High Transformation Temperatures." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-62379.
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The objective of this study is to develop high transformation temperature shape memory alloys (SMAs) for actuation applications at elevated temperatures. We developed a process to consolidate NiTi micron powders doped with Hf using Material Modification Inc.’s (MMI) proprietary Plasma Pressure Compaction process (P2C). NiTi and NiTiHf samples were characterized to identify the material’s microstructure and composition using Scanning Electron Microscopy (SEM) and Energy Dissipative Spectroscopy (EDS) for both as consolidated and heat treated materials. Chemical and porosity analyses were also conducted to track impurities and microstructure (grain size and porosity). Extensive thermo-mechanical testing of the NiTi and NiTiHf samples were conducted to determine phase transformation temperatures and mechanical properties (Young’s Modulus). An acoustic elastometer was used to obtain the phase transformation temperatures for both NiTi and NiTiHf samples. By doping the SMA powder with 10% Hf (atomic percent), we were able to realize an increase in the austenite finish temperature to over 160 C.
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Bjurstro¨m, Martin, and Carl-Gustaf Hjorth. "Producing HP Pump Barrels Utilizing Powder Metallurgy and Hot Isostatic Pressing." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-11209.
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The fabrication of near net shape powder metal (PM) components by hot isostatic pressing (HIP) has been an important manufacturing technology for steel and stainless steel alloys since about 1985. The manufacturing process involves inert gas atomization of powder, 3D CAD capsule design, sheet metal capsule fabrication and densification by HIP in very large pressure vessels. Since 1985, several thousand tonnes of parts have been produced. The major applications are found in the oil and gas industry especially in offshore applications, the industrial power generation industry, and traditional engineering industries. Typically, the components replace castings, forgings and fabricated parts and are produced in high alloy grades such as martensitic steels, austenitic stainless steels, duplex (ferritic/austenitic) stainless steels and nickel based superalloys. The application of PM/HIP near net shapes to pump barrels for medium to high pressure use has a number of advantages compared to the traditional forging and welding approach. First, the need for machining of the components is reduced to a minimum and welding during final assembly is reduced substantially. Mechanical properties of the PM/HIP parts are isotropic and equal to the best forged properties in the flow direction. This derives from the fine microstructure using powder powder and the uniform structure from the HIP process. Furthermore, when using the PM HIP process the parts are produced near net shape with supports, nozzles and flanges integrated. This significantly reduces manufacturing lead-time and gives greater design flexibility which improves cost for the final component. The PM HIP near net shape route has received approval from ASTM, NACE and API for specific steel, stainless steel and nickel base alloys. This paper reviews the manufacturing sequence for PM near net shapes and discusses the details of several successful applications. The application of the PM/HIP process to high pressure pump barrels is highlighted.
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Bjurstro¨m, Martin, and Carl-Gustaf Hjorth. "Producing HP Pump Barrels Utilizing Powder Metallurgy and Hot Isostatic Pressing." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77787.
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The fabrication of near net shape powder metal (PM) components by hot isostatic pressing (HIP) has been an important manufacturing technology for steel and stainless steel alloys since about 1985. The manufacturing process involves inert gas atomization of powder, 3D CAD capsule design, sheet metal capsule fabrication and densification by HIP in very large pressure vessels. Since 1985, several thousand tonnes of parts have been produced. The major applications are found in the oil and gas industry especially in offshore applications, the industrial power generation industry, and traditional engineering industries. Typically, the components replace castings, forgings and fabricated parts and are produced in high alloy grades such as martensitic steels, austenitic stainless steels, duplex (ferritic/austenitic) stainless steels and nickel based superalloys. The application of PM/HIP near net shapes to pump barrels for medium to high pressure use has a number of advantages compared to the traditional forging and welding approach. First, the need for machining of the components is reduced to a minimum and welding during final assembly is reduced substantially. Mechanical properties of the PM/HIP parts are isotropic and equal to the best forged properties in the flow direction. This derives from the fine microstructure using powder powder and the uniform structure from the HIP process. Furthermore, when using the PM HIP process the parts are produced near net shape with supports, nozzles and flanges integrated. This significantly reduces manufacturing lead-time and gives greater design flexibility which improves cost for the final component. The PM HIP near net shape route has received approval from ASTM, NACE and API for specific steel, stainless steel and nickel base alloys. This paper reviews the manufacturing sequence for PM near net shapes and discusses the details of several successful applications. The application of the PM/HIP process to high pressure pump barrels is highlighted.
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Rahman, Mosfequr, Masud Nawaz, Aniruddha Mitra, Nazanin Bassiri-Gharb, and John E. Jackson. "Experimental Investigation and Finite Element Modeling Analysis of Photostrictive Optical Actuators." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-88274.
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Photostrictive materials are lanthanum-modified lead zirconatetitanate (Pb, La)(Zr, Ti) O3 ceramics doped with WO3, called PLZT, exhibit large photostriction under uniform illumination of high-energy light. Photostrictive materials are ferrodielectric ceramics that have a photostrictive effect. Photostriction arises from a superposition of the photovoltaic effect, i.e. the generation of large voltage from the irradiation of light, and the converse-piezoelectric effect, i.e. expansion or contraction under the voltage applied. Photostrictive materials offer the potential for actuators with many advantages over traditional transducing electromechanical actuators made of shape memory alloys and electroceramics (piezoelectric and electrostrictive). Drawback of traditional actuators is that they require hard-wired connections to transmit the control signals which introduce electrical noise into the control signals; on the other hand PLZT actuators offer non-contact actuation, remote control, and are immune from electric/magnetic disturbances. The main goal of the research work is to investigate the feasibility of utilizing photostrictive materials as an optical actuator for Micro-Electro-Mechanical-Systems (MEMS) applications. In this investigation process both experimental and computational approaches have been implemented. In the experimental part of this research, a test set-up has been designed and developed to measure the photostriction effect of a PLZT thin film on a silicon wafer as smart beams. The experimental set-up includes high pressure short arc xenon lamp with lamp housing, power supply, lamp igniter, hot mirror, band pass filters, optical chopper, and laser sensor with sensor head and controller.1 μm PLZT thin film on the silicon wafer sample has been tested as a cantilever beam with different light intensities, and focusing the light at the different locations on the PLZT cantilever beam. The experiment has been performed for continuous and pulses of lights focusing on the PLZT optical actuator. An optical chopper was used to make pulses of light on the PLZT cantilever beam. Also, a computational finite element method useful for design of systems incorporating thin film photostrictive actuators has already been developed by the authors. The element has been implemented in an in-house finite element code. This derived finite element for continuous illumination of light on the photostrictive thin film has been used to investigate the application of photostrictive actuators for the different structures and various boundary conditions of microbeams with various actuator locations and length intensities. A successful conclusion of these tasks will affirm the potential of the PLZT optical actuator to use in the MEMS devices.
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Velukkudi Santhanam, Senthil Kumar, Ganesh Pasupathy, and Padmanabhan Kuppuswamy Anantha. "Determination of Superplastic Material Properties for Parent Material and Friction Stir Welded Joint of Al-Alloy AA6061-T6." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51368.
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Superplastic forming (SPF) takes the advantage of the metallurgical phenomenon of superplasticity (SP) to form complex and highly intricate bulk and sheet metal parts. SP refers to the extraordinary formability of certain metals and alloys, ceramics, composites (both metallic- and ceramic-based), dispersion strengthened materials, nanostructured materials and bulk metallic glasses, which allows them to suffer elongations of several hundred percent under the action of tensile forces. The superplastic forming characteristics of materials like aluminium, titanium and magnesium alloys have been clearly identified in order to produce complicated near-net shapes. These materials are used in the aeronautical manufacturing industry and automotive manufacturing industries due to the significant weight (by ∼ 30%) and cost (by ∼ 50%) saving that is possible. Some research work has proved superplastic forming of friction stir welded (FSW) joints also. The FSW joint efficiencies have been characterized by mechanical and metallurgical examination. Studies are also available on the behavior of FSW joints of similar and dissimilar metals. Information on the performance of friction stir welded joints during superplastic forming is rather limited, but it is important to achieve excellent properties in the friction stir welded joints also during superplastic forming. FSP (friction stir processing) – SPF (superplastic forming) is presently being promoted as a very viable near-net shape technology for making very large and complicated sheet metal products. To achieve this superplastic material parameters are much required in industry to develop new shapes. One has to understand the flow rule relationship and mechanics involved during sheet metal forming at high temperature to select the material and forming tool with selected process parameters. This paper deals with the determination of superplastic material properties of non-superplastic aluminum alloy AA6061-T6. The superplastic material properties like strain rate sensitivity index, flow stress and strain rate were determined for both the selected material and friction stir welded sheets at various tool rotation speeds. The superplastic free blow forming experiments were performed for various constant temperatures and pressure for the parent material. Similarly the superplastic free blow forming experiments were performed for the friction stir welded joint for various tool rotation speed at constant temperature. The methods were used to determine the material properties are straight line fit method and polynomial regression method. The superplastic forming height is significantly high in case of the FSW specimens at 2000 rpm, the initial forming rate is faster and the strain rate sensitivity index obtained is also higher when compared to the parent material properties. The strain rate sensitivity index obtained for friction stir welded specimen during superplastic forming was foundto have improved when compared to the parent material.
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Hjorth, Carl-Gustaf, and John C. Hebeisen. "Subsea Manifolds: An Alternate Fabrication Strategy Using HIP PM Near Net Shapes." In ASME 2005 Pressure Vessels and Piping Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pvp2005-71156.
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The fabrication of near net shape powder metal (PM) components by hot isostatic pressing (HIP) has been an important manufacturing technology for steel and stainless steel alloys since about 1985. The manufacturing process involves inert gas atomization of powder, 3D CAD capsule design, sheet metal capsule fabrication and densification by HIP in very large pressure vessels. Since 1985, several thousand tonnes of parts have been produced. The major applications are found in the oil and gas industry especially in offshore applications, the industrial power generation industry, the pulp and paper industry and in pharmaceuticals and traditional engineering industries. Typically, the components replace castings, forgings and fabricated parts and are produced in grades such as martensitic steels, austenitic and duplex (ferritic/austenitic) stainless steels and nickel- based superalloys. The application of HIP PM near net shapes to manifolds for medium to high pressure use has a number of advantages compared to the traditional forging and welding approach. First, the need for machining of the components is reduced to a minimum and welding during final assembly is reduced substantially. Manifolds by HIP design reduce the necessary welding by 70–90%. Mechanical properties of the HIP PM part are isotropic and equal to the best forged properties in the flow direction as is demonstrated below. This derives from the fine uniform microstructure of the PM parts. The PM parts are significantly lighter in weight because of the need to stiffen the forged component at the location of the weldment for the intersecting passageway — the PM parts can be smoothly blended into the intersection without need for welding. Furthermore, the PM HIP components can be made with significantly reduced manufacturing lead-time, greater design flexibility and improved cost for the final component. The PM HIP near net shape route has received approval from both ASTM [1,2,3] and NACE [4] for specific steel, stainless steel and nickel base alloys. This paper reviews the manufacturing sequence for PM near net shapes and discusses the details of several successful applications. The application of the HIP PM process to subsea manifolds is highlighted.
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Arnaboldi, Sergio, Paola Bassani, Carlo Alberto Biffi, Marco Carnevale, Nora Lecis, Antonietta Lo Conte, Barbara Previtali, and Ausonio Tuissi. "Microcutting of NiTiCu Alloy With Pulsed Fiber Laser." In ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2010. http://dx.doi.org/10.1115/esda2010-24943.
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Laser microcutting of thin sheets made of innovative and hard to machine materials, such as shape memory alloys (SMAs), is a very interesting topic. Innovative laser sources, such as pulsed fiber lasers, are becoming promising tools to be used in precise and fast operations in industrial applications. The positive features of this type of laser sources are high beam quality, strong focusability, high pulse energy and consequently high productivity. On the contrary the most important drawback is the pulse width in nanosecond regime, which means thermal effects in the workpiece. The investigated material is a nickel-titanium-copper (Ni40Ti50Cu10) alloy, a ternary SMA derived from NiTi binary alloy. In this work the effect of laser process parameters, such as number of laser passes, type of shielding gas, gas pressure and process speed on the cutting edge quality features, such as the amount of spatter and the kerf width, was studied. Finally functional characterization, i.e. differential scanning calorimetry (DSC) and mechanical measurements (nanoindentations), of the laser cutting edge was performed.