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 53 for “"deformation mechanism"”.
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Pressure Solution as a Deformation Mechanism in the Purgatory Conglomerate
Made available in DSpace on 2014-12-14T07:10:52Z (GMT). No. of bitstreams: 1 7913556.pdf: 7769578 bytes, checksum: 155ded23e12ea8ea7f1080586439949c (MD5) Previous issue date: 1978
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Experimental Quantification of the Phonon Drag Deformation Mechanism in Metals at Extreme Strain Rates
Extreme strain rate deformations, above 10⁶ s⁻¹, are seen across many fields of science and engineering; from meteorite impacts and impact induced crystallographic phase changes to high-speed machining and additive manufacturing. Despite the range of applications, many common high-rate impact …
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Modeling of twinning as a deformation mechanism in iron (bcc) crystals and iron-based alloys
We develop an analytical expression for twin nucleation stress in bcc metals considering GPFE (generalized planar fault energy) and the dislocations bounding the twin nucleus. We minimize the total energy to predict the twinning stress relying only on parameters that are obtained through atomistic …
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Free-radical maleation of poly(butylene adipate-co-terephthalate) in supercritical carbon dioxide and its effect on the percolation and deformation mechanism of layered silicate nanocomposites
The utilization of compostable polymers such as poly(butylene adipate-co-terephthalate) (PBAT) in single-use packaging applications can mitigate the water, solvents, and energy required for processing plastic waste. PBAT exhibits exceptional elongational properties, but its moderate water vapor …
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A Plasticity Theory of Metals Based on the Dislocation Substructures
… plasticity model developed from the microscopic deformation mechanism of metals is suggested. In the development of such a mechanistic model, the dislocation substructure of metals under different loadings is studied. Based on the observed substructure, the deformation mechanism of metals is …
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In situ diffraction investigations of mechanisms that lead to path dependent mechanical behaviours of nickel-titanium shape memory alloys
… deconvolute and interpret the role of multiple deformation mechanism has been on the top priority. Historically, lack of experimental capabilities to study in situ deformation mechanism like phase transformation and reorientation of variants was the main hindrance. But with development of modern …
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Fatigue and Fracture Behavior of High Strength and High Conductivity Copper Alloys for High Heat Flux Applications
… where dislocation glide is the dominant creep deformation mechanism. It was also determined that crack initiation and propagation at grain boundaries was accelerated under creep-fatigue loading conditions.
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Study of Nanowires Using Molecular Dynamics Simulations
… and grain growth. It was shown that during deformation, there is interplay between dislocation-mediated plasticity and grain boundary accommodation of plasticity through grain boundary sliding. To further understand the effect of stress on nanocrystalline materials we performed tensile tests …
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Multiscale Experimental Study on the Effect of Texture and Anisotropy on the Thermomechanical Response of Zirconium
… a possible dependence of dissipation on deformation mechanism. No correlation is found between deformation twinning and energy dissipation, and the appearance of energy storage in basal textured polycrystals is explained by the presence of localized deformation. Experimental and numerical …
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Deformation mechanisms in a polycrystalline Ni-based superalloy
… raised temperature window extends into a new deformation mechanism regime that needs to be explored and understood to be able to design and optimise new and existing Ni-based disc superalloys. For this purpose, this work investigates the deformation behaviour of the established coarse-grained …
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Densification and Mechanical Properties of Nanocrystalline FeAl
… and 525°C, similar to the decrease in deformation rate observed in sinterforging experiments. The stress exponent was calculated from the steady-state impression velocities at punching stresses of 400, 600 and 800 MPa, which are equivalent to conventional stresses of 130, 195 and …
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Carbon nanotube based electromechanical probes
… mechanical compression tests revealed a unique deformation mechanism of the CNT structures where continued compression results in successive buckle formation which later can serve as micro-bellows and elastic springs.
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Binder Film Thickness Effect on Aggregate Contact Behavior
… modeling is very important for understanding the deformation mechanism of the mixture. In this study, the contact modeling of asphalt mixture was reviewed and the numerical tools used to investigate the micromechanical behavior of asphalt mixture will also be introduced. By using the cabinet x-ray …
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Strength Development at Incompatible Polymer Interfaces
… coupled with a chain pull out microstructural deformation mechanism, which predicts that G$\sb{\rm IC}$ increases inversely with the interaction parameter, X. Microscopic investigation of the fracture surfaces revealed dissimilar fracture surfaces for a given pair, with evidence of stick-slip …
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Deformation at Low Temperatures in Single Crystal Ni-base Superalloys
… regime (above 700 °C). However, the study of deformation in the range of 20 °C to 700 °C is critical to understanding behaviour in the shanks of turbine blades in service, where the low-temperature properties of single crystal Ni-base superalloys have implications for fatigue and …
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Machining-induced damage mechanisms in KDP crystals
… This thesis aims to reveal the machining-induced deformation mechanisms of KDP with the aid of molecular dynamics (MD) analyses. To this end, a reliable potential function will be established to conduct some large-scale MD simulations. The MD analyses include simple loading conditions (tension and …
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A nonlinear viscoplastic double yield surface constitutive model for geologic materials
… of two components of strain for each deformation mechanism. In particular, in both the elastic and the plastic regimes a fast and a slow strain mechanism are assumed to be present. To this aim the constitutive model is based on two yield surfaces based on overstress viscoplasticity …
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Multiscale chemomechanics of polymer deformation under contact : predicting structure-property correlations from the bulk to the interphase
… as polystyrene and polycarbonate. The contact deformation mechanism near an amorphous polymer surface is found to scale with the surface area of contact, suggesting the dynamic formation of a structural interphase region. Chemical probe functionalization experiments are developed to explore the …
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Nanomechanical studies of metallic glasses at ambient and elevated temperatures
… display several unacceptable features upon deformation, including quasi-brittle failure along shear bands, extremely limited tensile ductility, and propensity for fatigue under cyclic loading. Though researchers have studied metallic glasses for the last fifty years, several fundamental …
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