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 23 for “"strain recovery."”.
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The effect of annealing on the microstructure of Cu-Al-Ni-Mn shape memory alloy microwires
… the shape memory effect and have achieved 6-8% strain recovery. This work investigates Cu-Al-Ni- Mn shape memory alloys in the form of microwires with the potential application in smart textiles. Wire microstructure and composition, transition temperatures, and strain recovery were analyzed …
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Cryogenic Shape Memory Alloy Actuators For Spaceport Technologies: Materials Characterization And Prototype Testing
… The shape change is associated with a large strain recovery as the material returns to its "remembered" shape. Their ability to act as both sensor and actuator has made them an attractive subject of study for numerous applications. SMAs have many characteristics which are advantageous in …
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Aerogels for energy storage applications: From shape memory materials to thermites and explosives
… were evaluated via four figures of merit namely strain fixity, strain recovery, strain recovery rate and fill factor. The morphologies of skeletal frameworks of those aerogels varied from micrometer sized particles with thick necks to bicontinuous structures, that are typical of spinodal …
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The theoretical behavior of a complex inelastic material
… to note the similarity between the stress-strain curves of the model and those of some aluminum alloys, Duralumin, magnesium and copperâ ¢ The creep and strain recovery curve of Fig. (20) is in close agreement with that of real metals discussed by Nadai (l5). This seems to indicate that the …
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Using surface topography to re-analyze gradients in mussel byssal threads
… Past work in the area has focused on full thread strain recovery dynamics and biochemical analysis of the collagenous and coating components in an attempt to understand the physical characteristics of the mussel byssal threads.
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Structural acoustic analysis of shape memory alloy hybrid composite panels
… are a class of materials which combine the strain recovery and elastic properties transformation capabilities of SMA fibers with the structural characteristics of advanced composite materials. This study utilizes the Rayleigh-Ritz method and finite panel acoustic radiation theory to …
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Actuation of shape memory polymer using magnetic fields for applications in medical devices
… Mechanical Thermal Analysis (DMTA), tensile strain recovery tests, and Differential Scanning Calorimetry (DSC) were used to measure the mechanical effects of various particle volume contents and sizes on shape memory polymer. These tests suggest that the proposed method of actuation is very …
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Deformation mechanisms in bulk nanostructured aluminum obtained after cryomilling and consolidation by spark plasma sintering
… that there is a significant fraction of plastic strain (11%) that can be recovered after unloading. High-energy synchrotron X-ray diffraction experiments revealed that, there is a correlation between plastic strain recovery and microstructural evolution detected during in-situ loading-unloading …
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Evaluation of viscous effects in crack tip fields in recycled asphalt pavement materials using digital image correlation
… Correlation (DIC) measurements. DIC measured the strain and displacement fields both at the far-field scale (40 microns/pixel) and at a near-field scale (8 microns/pixel), and allowed a local characterization of fracture mechanisms depending on the aggregate structure. Initial efforts focused on …
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A novel binary actuator using shape memory alloy
… displays. The actuator presented uses the strain recovery property 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 …
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Dowel-concrete contact characteristics
… using a novel laboratory setup of vibrating wire strain gauges embedded in both the dowel and concrete. The gages are set to measure the shrinkage strain induced in the concrete that surrounds the dowel as it cures causing the solidified concrete to clamp on the steel dowel. The measurements …
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Commissioning Of An Arc-melting/vacuum Quench Furnace Facility For Fabrication Of Ni-ti-fe Shape Memory Alloys, And The Characterization
Shape memory alloys when deformed can produce strains as high as 8%. Heating results in a phase transformation and associated recovery of all the accumulated strain, a phenomenon known as shape memory. This strain recovery can occur against large forces, resulting in their use as actuators. The …
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An investigation into the polyethylene extrudates produced by simultaneous orientation and high temperature quenching
… was analysed by tensile testing, cyclic strain recovery, shrinkage testing, density measurements and annealing in air and liquid metal at 117°C. It was found that the level of draw-down and the temperature of the quenching medium had a profound effect upon the resultant properties of the …
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Characterization of the Viscoelastic Fracture of Solvated Semi-Interpenetrating Polymer Network Silicone Hydrogels
… a "semi-infinite" strip geometry under constrained tension in which thin pre-cracked sheets of these cured hydrogels were exposed to several different loading conditions. Fracture tests were performed over a relevant range of temperatures and crosshead rates to determine and generate a …
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Design, Fabrication And Testing Of A Shape Memory Alloy Based Cryogenic Thermal Conduction Switch
Shape memory alloys (SMAs) can recover large strains (e.g., up to 8%) by undergoing a temperature-induced phase transformation. This strain recovery can occur against large forces, resulting in their use as actuators. The SMA elements in such actuators integrate both sensory and actuation …
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An Efficient Reduced Order Modeling Method for Analyzing Composite Beams Under Aeroelastic Loading
… while also allowing for accurate 3D stress and strain recovery. This efficient structural modeling would be ideal in the preliminary design optimization of a wing structure. Furthermore, in conjunction with an efficient unsteady aerodynamic model such as the doublet lattice method, the dynamic …
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Influence of tandem axle on pavement responses and weight limit equivalency
The student, Aravind Ramakrishnan, submitted this Thesis for approval on 2020-12-08 at 12:33.
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ASTM assessment of a novel shoulder prosthetic design: measurement of glenoid edge motion in three degrees of freedom
… from this thesis was that the deformation and strain recovery of the glenoid components played a larger role in edge motion than the expected ‘rocking' and this observation should be accounted for when developing new glenoid designs.
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Phase field modeling of the defect evolution and failure
<p>The plastic recovery processes in ultrafine and nano grained metals and the yield criteria and failure mechanisms in polymer matrix composite are the two major topics in this work.</p> <p>In the first part of the work, a phase field dislocation dynamics (PFDD) approach is introduced, which …
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Transmission Electron Microscopy Studies In Shape Memory Alloys
… induced transformation is associated with strain recovery that results in the shape memory effect. Ternary elemental additions such as Fe can additionally introduce an intermediate rhombohedral (R) phase between the cubic and monoclinic phase transformation. This work was initiated with the …
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