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 62 for “"fatigue cracking"”.
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Fatigue cracking of lumber bandsaw blades
The focus of this research is on the fatigue cracking problem in the tooth gullet region of wide handsaw blades used in the lumber industry. This thesis presents both the theory and the experiment aspects of this research in terms of the tasks defined as follows. The current literature was reviewed …
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An integrated approach to fatigue cracking, reliability and inspection of offshore structures
This thesis describes an integrated approach to fatigue cracking, reliability and inspection of offshore structures. The basis of the approach is statistical in nature and draws on recent experimental data and field measurements. It is intended as a working tool for those engaged in design, …
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Development of Pre-Stressed Retrofit Strategies for Mitigating Fatigue Cracking in Steel Waterway Lock Gate Components
… create economic ripples throughout the nation. Fatigue and corrosion are key causes of unscheduled service interruptions, degrading lock gate components over time. Additionally, because lock gates are submerged during operation, crack detection prior to component failure can be difficult, and …
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An active-path-dissolution model for corrosion-fatigue cracking of drill-pipe steels in offshore drilling environments
The corrosion-fatigue life of drill-pipe steels in simulated offshore-drilling environments was predicted using an analytical model. This model, named the Active-Path-Dissolution (APD) model, simulates a sequence of three corrosion-fatigue processes: chemical notching process, microcrack …
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Preliminary Study of Highway Pavement and Materials
… of in-place air voids and other factors on fatigue cracking using Long-Term Pavement Performance data, (b) fracture properties of asphalt concrete in a semicircular bend (SCB) test using a noncontact camera and crosshead movement, and (c) hot applied modified-binder-chip-seal field …
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Development of Mechanistic-Empirical Principles for Jointed Plain Concrete Pavement Fatigue Design
… effect on the observed critical distresses and fatigue life of rigid, pavements. A mechanistic analysis and design software (RadiCAL) was developed employing an influence line approach in conjunction with Miner's Hypothesis to calculate the fatigue damage at numerous locations in the slab for …
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Performance Evaluation of Asphalt Mixtures with Tire Rubber Modified Binder
… by means of dynamic modulus master curves, fatigue cracking, permanent deformation, and reflective cracking resistance. Dynamic modulus tests were conducted using the Asphalt Mixture Performance Tester (AMPT) device and the master curves were built using AASHTO R84 standard procedure for …
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Classification of In-Flight Fatigue Cracks in Aircraft Structures using Acoustic Emission and Neural Networks
… deals with the analysis and classification of fatigue cracks in aircraft structures. The particular structure that was examined was the vertical tail section of a Cessna T-303 Crusader aircraft. The analysis was performed using the nondestructive evaluation technique known as acoustic emission …
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Evaluation of Superpave mixtures in West Virginia using the asphalt pavement analyzer
… evaluate rutting, moisture susceptibility, and fatigue cracking.;This research focused on establishing whether there are relationships between the APA rutting potential and field performance. The APA was used to measure the rutting potential of Superpave mixes constructed throughout the state. …
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Implementation of mechanistic-empirical approach for structural design of hydrated lime modified flexible pavement
… advantages of hydrated lime in the resistance to fatigue cracking and permanent deformation are utilized as main factors in the adopted Mechanistic-Empirical approach of this study. To achieve the objective of this study, three types of asphalt concrete mixtures that represent the pavement …
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Characterization of Ohio Traffic Data for Integration into the Mechanistic-Empirical Pavement Design
… pavement included longitudinal (top-down) fatigue cracking, alligator (bottom-up) fatigue cracking, transverse (low-temperature) cracking, rutting, and smoothness (expressed using IRI), while key performance parameters for the rigid pavement included transverse cracking (% slabs cracked), …
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Experimental and modelling studies of pit-to-crack transition under corrosion fatigue conditions
Corrosion fatigue cracking is a material degradation mechanism which occurs when materials are under cyclic loading and in a corrosive environment. The joint effect of both mechanical and environmental factors makes it one of the most challenging topics in the study of material degradation. The …
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Accurate characterisation of surface fatigue cracks (in steels) using the AC potential drop NDT technique
… variously shaped and oriented surface breaking fatigue cracks. The ACPD method was reviewed to establish its viability as an NDT technique, and to understand the response of the output to fatigue cracking. The proposed system using a mains power source with a frequency of 50Hz was investigated …
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Redesign and shock analysis of HALIFAX class frigate gas turbine uptake structure
… Canadian Navy have experienced thermally-induced fatigue cracking since soon after the commissioning of these ships. The uptake structure is heavily stiffened in order to meet shock resistance requirements. Unfortunately, the result has been that thermal expansion of the uptake shell is …
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Optimization of Rib-To-Deck Welds for Steel Orthotropic Bridge Decks
… its light weight and fast construction. However fatigue cracking problems on the welds have been observed in many countries. Rib-to-deck welds need special care since they are directly under wheel loads, which cause large local stress variations and stress reversals. Currently the only …
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A Numerical Based Determination of Stress Intensity Factors for Partially Cracked Flexural I-shaped Cross-sections
… modern steel structures are designed to resist fatigue cracking from service loads, cracks in the tension flanges of steel bridge girders have been observed as a result of stress concentrations, design errors, welding quality control, and vehicular impacts. Cracks can grow in size with time and …
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Use of phase angle in lieu of critical crack tip opening displacement for asphalt binder specification
… Shear Rheometer to determine the resistance to fatigue cracking, permanent deformation, performance at high, intermediate and low temperatures. The Double-Edge-Notched Tension (DENT) test was performed to measure the ductile strain tolerance in the presence of critical tensile stresses. …
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In-Flight Fatigue Crack Monitoring of an Aircraft Engine Cowling
… the feasibility of implementing an in-flight fatigue crack monitoring system in an airplane to identify fatigue crack growth. An acoustic emission data acquisition system coupled with a Kohonen self organizing map neural network were used to perform the analysis.</p> <p>Fatigue cracking was …
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Balanced asphalt mix design and pavement distress predictive models based on machine learning
… to resist pavement distress, such as rutting, cracking, IRI (international roughness index), etc., is still the trend of future asphalt mix design. The service life of asphalt pavement mainly depends on the properties of the asphalt mixture. Whether asphalt mixture has good properties also …
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Acoustic Emission Fatigue Crack Monitoring of a Simulated Aircraft Fuselage Structure
… purpose of this research was to replicate the fatigue cracking that occurs in aircraft placed under loads from cyclical compression and decompression. As a fatigue crack grows, it releases energy in the form of acoustic emissions. These emissions are transmitted through the structure in waves, …
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