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 84 for “"spalling"”.
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Material properties related to fire spalling of concrete
… 100 years of research, the fundamentals of fire spalling of concrete are not yet fully understood. Many different theories exist, each trying to describe the coupling between different phenomenon leading to fire spalling. Some of these phenomenon have been investigated and are presented in this …
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Theoretical study of thermal spalling of brittle materials
In this work several problems related to thermal spalling are considered. First, a novel approximate technique to solve general linear heat-conduction problems with changing boundary conditions and locations is proposed. The technique is based on the concept of linear superposition and the …
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Numerical simulation of fragmentation and spalling and parallelization of a spacetime finite element code
We present a study of the problem of spalling and fragmentation using a Space Time Discontinuous Galerkin Finite Element Method (SDGFEM) coupled with an interfacial damage model. SDGFEM offers many advantages over conventional finite element methods. These include element-wise conservation, linear …
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Development of internal pressure monitoring system for control of explosive spalling in refractory castables
… pressure exceeds material strength, explosive spalling results. A probe capable of measuring internal steam pressures"in-situ" has been developed and tested. Correlation of cement calorimetry and pressure data suggests that castable heating schedules can be modified to reduce explosive spalling.
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Investigating the Optimization of Terrestrial Laser Scanning Procedures for the Analysis of Concrete Bridge Pier Spalling
… to scan surface defects of structures, such as spalling, to better understand its overall condition. However, much of the research conducted regarding TLS only accounts for its implementation rather than improving the process itself. Due to this, there are no general guidelines or standards for …
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An investigation into the characterisation of the spalling behaviour of Polycrystalline Diamond Compact(PDC) cutters under impact loading conditions
… investigation into the identification of the spalling mechanisms of polycrystalline diamond compact (PDC) cutters and the effect of stress wave shape on the degree of spalling was performed using the split-Hopkinson pressure bar (SHPB) apparatus. The PDC cutters were loaded under specific …
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Response of high strength concrete columns under fire-induced biaxial bending
… can arise due to eccentricity in loading, uneven spalling, or due to significant thermal gradients generated through 1-, 2-, or 3-sides of fire exposure. High strength concrete (HSC) columns are especially prone to such biaxial bending due to fire induced spalling. However, there is limited data …
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Scale-model investigation of brittle tunnel failure using a true-triaxial device
… have led to severe consequences such as spalling, violent rock ejection or rock burst, and tunnel collapse. Detached rocks from the tunnel boundary not only compromise the structural integrity of tunnels but also pose significant safety risks to personnel and construction equipment, …
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Residual Strength of Ultra-High Performance Concrete After Exposure to Elevated Temperatures
… fire-resistant mixture exhibited no explosive spalling during heating but demonstrated reduced compressive strength at temperatures over 200<sup>o</sup>C (392<sup>o</sup>F). Durations greater than one hour had little effect on the residual compressive strength of the cylinders. Unlike the …
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Calibrated mechanistic design procedure for jointed plain concrete pavements
… transverse cracking, joint faulting and joint spalling.
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3D numerical modelling of brittle failure in mechanized excavation of deep tunnels
… brittle failure of hard rocks, leading to spalling (formation of rock slabs) and/or rockbursting (violent ejection of rock fragments). This thesis initially deals with brittle failure, both in laboratory tests (uniaxial and/or triaxial) and in tunnelling, with a special interest in TBM …
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Vertical gallium nitride power devices on bulk native substrates
… The thesis concludes with the demonstration of spalling off the bulk GaN substrate after device fabrication. Thanks to the substrate spalling technology, the on resistance of the device can be further reduced and the bulk GaN substrate could possibly be reused to save cost.
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Experimental study of UHPC with high fire resistance and meso-scale modelling
… up to 80% after exposure to 800 °C and explosive spalling is a common disaster to UHPCs. To develop a UHPC with high fire resistance, a total of six UHPC mixtures were designed and tested after subjected to elevated temperatures up to 1000 °C in this study. The effects of aggregate type, fibre …
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Three-dimensional boundary element and experimental analysis of lubricant ceramic surface ring cracks in rolling contact.
… size,lubricant and material type. Ring crack spalling failure is not only influenced by sub-surface fatigue crack propagation but also strongly influenced by secondary surface cracks. The formation of the secondary surface cracks is a key factor which dominates spalling of rolling contact …
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Moisture Conditions and Frost Resistance of Concrete in Hydraulic Structures
… in this work confirm this deterioration process. Spalling of concrete has been observed below the water level in water retaining concrete structures subjected to long periods of freezing temperatures in winter. The hypothesis is that either poor quality concrete or the effects of aging make …
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Subsidence Cracking of Concrete Over Steel Reinforcement Bar in Bridge Decks
… corrosion of the reinforcing steel resulting in spalling of the cover concrete. Concrete specimens with 16 mm (# 5) diameter bars were cast with various cover depths, bar spacing and two concrete mixture types to determine the influence that epoxy coated reinforcement, cement type and bar spacing …
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Seismic Behaviour of Grouted Connections in Precast Concrete Panels
… modes, being reinforcement fracture, concrete spalling without metal duct pull out, and concrete spalling with metal duct pull-out. An alternative simple analytical method was proposed in order to determine the type of connection failure without using a time-consuming finite element method. …
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Physics-Informed Diagnostic and Prognostic Models for Rolling Element Bearings Using Oil Debris Data
… diagnostic and prognostic models due to spalling in the inner raceway. This is achieved by integrating real-time oil debris data and a comprehensive understanding of the underlying bearing degradation mechanisms. The diagnostic model incorporates spall physical information, a heuristic …
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