Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 120 for “"Shape memory alloy"”.
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Prestressing Concrete with Shape Memory Alloy Fibers
… large, straight members. During the last decade, shape memory alloys (SMA) have become more prevalent in engineering and civil engineering applications. The shape memory effect refers to the contraction of the SMA when it is heated to its austenite phase. When a prestrain is induced in the SMA, it …
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Advancing Architecture through Shape Memory Alloy Actuators
This thesis explores the integration of Shape Memory Alloy (SMA) actuators into architectural design, proposing a comprehensive knowledge framework that bridges material science, responsive technologies, and architectural theory. Motivated by the ontological and experiential implications of kinetic …
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Functionalized Shape Memory Alloy Microfilament Twisted Yarn Structures
… devices. Of the smart material technologies, shape memory alloys (SMA) exhibit significant strain recoverability, large actuation deformations and forces, and multipurpose damping abilities through thermally dependent solid-state phase transformations. Monofilament-based SMA systems have …
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A novel binary actuator using shape memory alloy
… of the martensitic transformation of Nitinol, a Shape Memory Alloy (SMA), to generate the actuation force. A compliant bistable mechanism provides the restoring force that pre- strains the martensitic Nitinol, and thus makes the actuator binary. Binary actuation alleviates some of the problems …
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Using shape memory alloy as dampers : design methodology
Many shape memory alloy (SMA) material models have been proposed in the literature, but most are suited only to forward analysis and not to design. This project proposes a generalized friction element, the lambda box, to model the stress-strain curve of SMA during pseudoelasticity. Simulation is …
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Symbiotic Encounter: Shape Memory Alloy Actuators in Architecture
… reference on the effective integration of shape memory alloys into architectural design and design. Despite growing interest in SMAs for kinetic structures and adaptive facades, there is currently a fragmented understanding of how to leverage their unique properties in the built …
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The VT1 Shape Memory Alloy Heat Engine Design
The invention of shape memory alloys spurred a period of intense interest in the area of heat engines in the late 70's and early 80's. It was believed that these engines could use heat from low temperature sources such as solar heated water, geothermal hot water and rejected heat from conventional …
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Thermomechanical Response of Shape Memory Alloy Hybrid Composites
This study examines the use of embedded shape memory alloy (SMA)actuators for adaptive control of the themomechanical response of composite structures. Control of static and dynamic responses are demonstrated including thermal buckling, thermal post-buckling, vibration, sonic fatigue, and acoustic …
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Surface integrity of laser cutting nitinol shape memory alloy
… Nitinol, a nearly equiatomic nickel-titanium shape memory alloy, has been widely used to fabricate vascular stents due to the excellent mechanical properties, fatigue and corrosion resistance, and biocompatibility. The challenges for manufacturing Nitinol stents are manifested in two aspects: …
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Shape memory alloy rotary actuator for CubeSat deployable structures
… multiple-use actuator by using a Joule-heated shape memory alloy-based hinge. The hinge uses two shape memory alloy strips which are trained in opposite directions and mounted into a rotary actuator. Two different shape memory alloy geometries are explored: a rectangular cross-section and a …
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Issues in the design of shape memory alloy actuators
This thesis considers the application of shape memory alloy (SMA) actuators for shape control of the undertray of a sports car. By deforming the shape of the structure that provides aerodynamic stability to the car, we expect to improve the overall performance of the vehicle by adapting its …
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In search of martensite : titanium-tantalum shape-memory alloy
… medical implants and devices that rely on the shape-memory (SME) and superelastic properties of various nickel-based alloys [8]. Unfortunately, there is also serious concern about the toxicity of nickel. Titanium based shape-memory alloys have been noted as potentially non-toxic replacements of …
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Self-Regulated Thermal Management with Shape-Memory Alloy Torsional Tubes
… to an increase in component energy density. Shape-memory alloy actuators, which respond with a mechanical shape recovery to variations in temperature, can be used as self-regulated thermal management actuators that are able to respond to environmental thermal changes autonomously. In this …
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Design and Analysis of Energy Harvesting with Shape Memory Alloy
Shape memory alloys (SMAs) are metallic alloys made of Titanium & Nickel to retain a specific shape by undergoing a heating process. The shape memorization occurs via a temperature dependent phase transformation process between two crystal structures, austenite phase and martensite phase. Typical …
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Investigation of Residual Stresses in Shape Memory Alloy (Sma) Composites
A three-phase concentric cylinder micromechanics model and an SMA composite thermoelastic beam theory were developed to analyze the micromechanical and structural-level thermal and transformational stresses for nitinol composites induced by nitinol wires embedded in a host matrix. A series of …
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Superelastic shape memory alloy composite bars for reinforcing concrete structures
Superelastic shape memory alloys (SMAs) are a class of metallic alloys that have the unique property of being able to undergo large amounts of plastic strain while remaining elastic and dissipating energy. This thesis explored a strategy for adding ductility and energy dissipation to FRP …
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A rotary shape memory alloy actuator for CubeSat deployable structures
… deployable structures. We propose using a shape memory alloy (SMA) actuator to meet this need. A SMA can be annealed at high temperatures to remember a trained shape. Upon cool down, the SMA element transforms to the martensite phase and is easily deformed. When the element is heated above …
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Grain constraint and size effects in shape memory alloy microwires
Shape memory alloys exhibit interesting and useful properties, such as the shape memory effect and superelasticity. Among the many alloy families that have been shown to exhibit shape memory properties the ones based on copper are interesting because they are relatively inexpensive and show …
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Design and characterization of acoustic pulse shape memory alloy actuators
Single crystal Ni-Mn-Ga ferromagnetic shape memory alloys (FSMAs) are active materials which produce strain when a magnetic field is applied. The large saturation strain (6%) of Ni-Mn-Ga, and material energy density comparable to piezoelectric ceramics make Ni- Mn-Ga an interesting active material. …
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A torso haptic display based on shape memory alloy actuators
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2003.
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