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 32 for “"Crack Patterns"”.
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The dynamics of crack patterns in soil induced by desiccation
Many soil types develop cracks due to desiccation. The resulting crack patterns were simulated with the help of a network of springs, representing the breaking material. A spring breaks if the tensile stress on it exceeds a threshold. Based on existing models in the literature a numerical model was …
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Crack Patterns in Thin Films and X-ray Optics Thermal Deformations
… of their reflective performance and even film cracking. Therefore, analysis of the thermally-induced deformations and stresses in the X-ray optical elements is important. The presented work is organized in two major parts. The first part examines formation of the peculiar periodic crack …
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Analysis of crack patterns in reinforced concrete frames under seismic excitation
… these different types of concrete. Then cracks patterns analyses are run at the joint between beam and column. In that part, theoretical approach precedes experimental application. Finally, explanation about benefits and advantages of using SFRC in joints of buildings subjected to seismic …
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Experimental study of fracture energy for foamed concrete
… is the main parameter that governs damage and cracks mechanisms of any structural components. Therefore, the present study aims to experimentally investigate the fracture energy of foamed concrete using beam specimens with U-notch and V-notch through a three-point bending test. Fifty-two (52) …
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Low velocity impact response of rc beam with artificial polyethylene aggregate as concrete block infill
… results, the impact force, displacement and crack patterns were affected by the impact load. For RCAI specimens, the impact force was larger but smaller displacement value was observed, compared to the NRC specimens. Furthermore, the width of the cracks generated in the RCAI specimens near …
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Drying of colloidal suspension drops : pattern formation and mechanical deformation
… drying stresses generate regularly spaced radial cracks. The crack patterns define four different regimes which we relate to experimental measurements of the deposit shape. The radial cracks separate the deposit into a multitude of petals. Due to the negative water pressure inside the pores of the …
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Fabrication of Directed Nanowire Networks Through Stress -Guided Self -Assembly
… the nature of multilayer fracture and resulting crack patterns under various stress states is followed by a novel, bottom-up technique for nanowire fabrication based on controlled cracking of thin SiO2 coatings on Si substrates, where each crack with its nanoscale opening serves as a mold to be …
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Fracture Morphologies in Particulate Suspensions
Films of a colloidal suspension solidify and crack during drying and discontinuously shearthickening suspensions shear-jam and fracture under applied stress. In both systems, the morphology and dynamics of fracture reveal the internal stresses in the material: craquelures in old paintings reveal …
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Lagrangian methods for ballistic impact simulations/
… shown to capture experimentally observed radial crack patterns. An adaptive remeshing strategy using finite elements is then explored and applied, with limited success, to the problem of predicting the transition from dwell to penetration for long-rod penetrators impacting confined ceramic …
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Investigation of the Strength and Ductility of Reinforced Concrete Beams Strengthed with CFRP Laminates
… specimen; the moment, deflection, CFRP strain, crack patterns, and mode of failure are discussed. The results included an increase in load capacity with respect for the number of CFRP layers applied for both orientations. Also, the ductility of the beams were reduced by adding CFRP orientations.
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Microstructure-based modeling of damage and healing in salt rock with application to geological storage
… rock properties. The evolution of pores and cracks during thermo-hydro-chemo-mechanical coupled processes governs the variations of macroscopic properties. This research investigates the modeling of damage and healing in rocks with applications in geological storage. This presentation focuses …
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Field monitoring of integral abutment bridge approach slabs
… lower maintenance costs and longer service life. Cracking of approach slabs immediately adjacent to IABs, which requires maintenance, repair, and even premature replacement, has been observed recently at a number of IABs in Illinois. Agency survey across the U.S. indicates that other states have …
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Fatigue and static behaviour of post-tensioned steel-concrete composite beams
… post-tensioning (PT) as a retrofit on the cyclic crack patterns on the concrete flange, cyclic incremental deformations, and strains were investigated with various pre-fatigue conditions. The pre-fatigue conditions included exposure to outdoor environmental changes for 365 days, plastic …
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A Machine Learning and Computer Vision Framework for Damage Characterization and Structural Behavior Prediction
… in RC beams, slabs, and panels based on surface crack pattern images. The predictive models have been generated and tested using image data sets obtained from earlier published studies, which together provide about 1,500 crack pattern images captured from about 170 individual RC beam, slab, and …
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Hydraulic fracturing through 3D printing and lattice modelling
… bar (SHPB) system for investigating the dynamic crack propagation and coalescence. In addition to the high accuracy and flexibility in specimen preparation, the desired fracture paths captured by the high-speed camera affirm the suitability of the powder-based material on fracturing test. …
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Short-term and time-dependent flexural behaviour of steel fibre-reinforced reactive powder concrete
… under short-term loading to determine their cracking and ultimate moment capacity. The remaining 4 beams were used to investigate the time-dependent flexural behaviour of prestressed SF-RPC slabs. The material properties were measured using a range of short-term tests and included the …
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Shear strengthening and repair of deep beams with and without web reinforcement using near-surface mounted CFRP bars
… to G5 consists of initially strengthened or pre-cracked and repaired deep beams with CFRP NSM bars with different schemes and orientations. Other variables included beams with and without web reinforcements. The selected orientations for all CFRP NSM bars were either at 0/90 or 45/135 degrees and …
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Phase field modeling of dynamic brittle fracture at finite strains
… body through the propagation of one or several cracks. Computational methods for fracture mechanics are becoming increasingly important in dealing with the nucleation and propagation of these cracks. One method is the phase field approach, which approximates sharp crack discontinuities with a …
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Shear strengthening of pre-cracked and non pre cracked reinforced concrete continuous beams using bi directional CFRP strips
… similar behaviour in terms of shear capacity and crack patterns. Three existing theoretical models; ACI 440, Khalifa and Nanni and fib models were adopted for theoretical comparison of shear capacity contributed by CFRP, Vf while for shear capacity contributed by concrete, Vc and stirrups, Vs, the …
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Phase field modeling of the defect evolution and failure
… is presented to study the onset of yielding and crack propagation in polymer matrix composite. The effect of two damage parameters, the fracture toughness <em>Gc</em> and crack length scale parameter <em>l0, </em>are first investigated. The former is shown to determine the energy needed during …
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