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 19 of 19 for “"Surface cracking"”.
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Hydrogen induced surface cracking of two orthopedic implant alloys
… absence of externally applied stress, induced surface cracking in 316 stainless steel and cobalt based ZIMALOY. Hot Isostatic Pressed (H.I.P.) ZIMALOY showed less susceptibility to surface cracking than 316 stainless steel samples. The susceptibility of 316 stainless steel to surface cracking …
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Development of domain integral and generalized finite element methods for three dimensional analysis of near-surface cracking in flexible pavements
… in the analysis of classical bottom-up fatigue cracking of relatively thin flexible pavements, where tensile stresses and strains govern the behavior at the asphalt layer. However, elastic theories are incapable of predicting other pavement distresses, including near-surface cracking. Similarly, …
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Understanding forgeability in highly reinforced cast-and-wrought superalloys
… microstructural evolution, and the occurrence of surface cracking in the hot die forging of highly γ′-reinforced cast-and-wrought nickel-based superalloys. The theory postulates that surface cracking is controlled by the dissolution of the secondary γ′ phase and its subsequent reprecipitation as …
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Establishing the Location and Magnitude of Critical Tensile Strains and Octahedral Shear Stresses for Design of Asphalt Concrete Pavement Systems
… years, our pavements experienced premature surface cracking and rutting. Traditional mechanistic design procedures account for two modes of failure in asphalt pavements: Fatigue and Rutting.
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Analysis of tire-pavement interaction and pavement responses using a decoupled modeling approach
… between a tire and a non-deformable pavement surface was simulated. The tire is modeled as a composite structure including rubber and reinforcement. The steady-state tire rolling process was simulated using an Arbitrary Lagrangian Eulerian (ALE) formulation. The developed tire-pavement …
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Parameters Influencing the Corrosion Protection Service Life of Epoxy Coated Reinforcing Steel in Virginia Bridge Decks
… A chloride solution was applied to the surface on a weekly cycle (for a total duration of 3.06 years) and a nondestructive electrochemical testing was performed on each core on a monthly cycle. Cores were also inspected for surface cracks, the thermal properties of the epoxy coating, and …
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Design and performance of cost-effective ultra high performance concrete for bridge deck overlays
… humidity and temperature gradients, as well as cracking and delamination were monitored over time. Test results indicate that the designed UHPC mixtures exhibited relatively low autogenous shrinkage and drying shrinkage. The G50 mixture had the lowest autogenous and drying shrinkage of 255 µm/m …
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Processing and Properties of Particulate Reinforced Carbon Matrix Composites
… However, at increased temperature, more surface cracking was observed, leading to the conclusion that an excessively high temperature is detrimental to mechanical properties. Finally, rutile TiO2 was formed as a result of the heat treatment process. In considering environmental impact, …
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Numerical modelling of the aluminium extrusion process and comparison with results obtained from industrially extruded complex sections.
… the required load, the temperature evolution, surface formation of the extrudate and material flow during the process. The effect of varying process conditions on the selected geometries were investigated and verified by means of experiment. Considering the difficulty in performing the …
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Effects of porosity on surface chemistry, wetting, and percolation in porous tungsten, liquid lithium hybrid plasma facing component system
… including enhanced hydrogen retention, surface cracking and surface morphology evolution that may lead to macro-level impurity emission into the plasma. An alternative approach to conventional monolithic tungsten-based PFC materials is to introduce designs to mitigate known shortcomings …
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Investigation on the mechanisms of block cracking in asphalt pavements
Block cracking in asphalt pavements is a primary form of surface cracking but has been the subject of very few scientific investigations. The extensive nature of this cracking form often leads to significant maintenance costs and reduces the ride quality and service life of the pavement surface. …
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Modeling of sheet metal fracture for shell finite elements with component level validation
… fracture not preceded by localized necking, aka surface cracking, and (3) biaxial fracture in consequence of localized necking. Validation is made in two steps. First, the model accuracy is evaluated purely numerically, compared to solid elements. Secondly, a comprehensive experimental validation …
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Investigation of Fatigue Properties of Superpave HMA at the Virginia Smart Road
… specimens, despite visual observation of damage (surface cracking) in the field-compacted specimens. Testing performed on one mixture to determine the influence of different loading frequencies showed that fatigue life was independent of the requencies tested. Investigation of rest period …
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Irradiation effects on geopolymer and additively manufactured 316H stainless steel and porosity in equine hoof wall
… modulus, and a 23% decrease in contact depth. Surface cracking was observed, attributed to ion implantation and reduced water content, highlighting its potential for shielding applications with further optimization. Next, we studied the irradiation response of AM 316H SS, produced via laser …
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Copper contamination in end-of-life steel recycling, developing a new strategy from million-tonnes to milligrams
… steel segregates during hot rolling, causing surface cracking and defects that are unacceptable for high-quality flat products. This thesis characterizes copper in the global steel system, evaluates the energy requirements of possible extraction processes and presents experimental results to …
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Abrasion-corrosion of downhole drill tool components
… contact conditions and can lead to accelerated surface degradation and even catastrophic failures. A Scanning Electron Microscope (SEM) investigation of worn drill-tool components revealed the presence of micro-scale (by abrasives similar size to the carbide grains i.e. less than 5 ?m) and …
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Multiscale materials design of natural exoskeletons : fish armor
… effective material properties, circumferential surface cracking, plastic dissipation in the underlying dentin layer, stress redistribution around the interfaces with suppression of interfacial failure. Secondly, since the outmost ganoine is structurally anisotropic, the roles of anisotropy of …
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Grinding of advanced ceramic materials: experimental and theoretical investigation into crack initiation and propagation
… from shaping ceramics whilst conserving their surface integrity, strength and high quality surface finish. Manufacturing processes such as grinding with diamond bonded wheels present one solution. The use of a diamond grinding wheel on the surface of ceramics, creates a complex system of …
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Modelización del deterioro de tableros de puentes de hormigón por difusión de cloruros y corrosión de la armadura pasiva
… initiation time prediction, basic variables like surface chloride content or threshold chloride concentration are not precisely defined yet. Regarding propagation stage, corrosion provokes the reinforcement cross-section reduction and the loss of bond between concrete and steel, as well as …