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 12 of 12 for “"R-curve"”.
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Quantification and Characterization of Fracture Resistance in Asphalt Concrete Based on R-Curve Method
… and propagation of cracks. The Resistance Curve method, or R-Curve, is widely applied in characterizing various materials including, but not limited to, metal, polymer, rock, and composite. This research R-Curve method introduces asphalt concrete through a stepwise approach. First, in …
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Crack growth resistance in nuclear graphite
R-curve behaviour is often used for evaluating crack growth resistance in quasibrittle materials but few studies have focused on polycrystalline graphite. In this study, R-curve behaviour in three commercial grade nuclear graphites, of varying structure and properties, is compared using an optical …
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Performance Evaluation and Durability Studies of Adhesive Bonds
… to a simple rule of mixture, while reverse R-curve and R-curve type trends were observed in the regions surrounding weak interface patterns. Under mixed mode conditions such that bonding surface with patterns is subjected to axial tension, fracture energy did not show R-curve type trends while …
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Investigation of a Model for the Study of Digital Perfusion in Equine Laminitis Using an Extract of Black Walnut (Juglans Nigra)
… to potentiate the concentration-response (C-R) curve for epinephrine-induced constriction of isolated equine digital vessels in the presence of hydrocortisone. Clinical signs, hematologic and serum biochemical parameters, plasma epinephrine and cortisol concentrations, distribution of digital …
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A Numerical Investigation of Loading Rate Effects on Pre-Cracked Charpy V-Notch Specimens
… studies focusing on numerically generated R-curves quantify the relative influence of impact velocity, material strain rate sensitivity, and properties of the computational cells (thickness and initial cell porosity). In all cases, impact loading elevates significantly the R-curve by …
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Models of stand basal area distributions, individual tree basal area growth, and height-diameter relationships for loblolly pine
… Louisiana. Five height-diameter (basal area) curves were examined to determine which was most appropriate for the data set utilized. The model H = a + b log(BA), where H denotes height and BA denotes basal area, was chosen as best, based on several fit and prediction oriented statistics. A …
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High temperature fracture behaviour of laser-powder bed fusion produced nickel superalloy
… based on ASTM E1820 was used to generate a J–R curve and determine the 𝐽𝐼𝐶 of the specimens. These L-PBF produced specimen fracture toughnesses were compared to those reported in the literature for both wrought and L-PBF produced IN718. The results showed that, at 650 °C, laser-powder bed fusion …
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Factors Affecting the Structural Integrity of Wood-Based Composites: Elevated Temperature and Adhesive Bonding
… rotary-peeled veneers) demonstrates a rising R-curve behavior (an increase in the fracture toughness with crack length) when bonded on the loose side. This increase in fracture toughness is observed to be a result of adhesive-substrate interaction, which is a developing process zone behind the …
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Improvement in mechanical properties through structural hierarchies in bio-inspired materials
… present in the structure. The importance of R-curve behavior, i.e., toughness change with the advance of a crack in the structure. to the defect-tolerance length scale is also established. These findings showcase the validity of using design principles obtained from biological materials for …
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Fatigue crack propagation in functionally graded materials
Propagation of cracks in functionally graded materials (FGMs) under cyclic loading was investigated via experiments and finite element (FE) analysis. Alumina-epoxy composites with an interpenetrating-network structure and tailored spatial variation in composition were produced via a multi-step …
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Testování lomové houževnatosti za vysokých teplot s využitím miniaturních CT těles
Tato diplomová práce se zabývá testováním lomové houževnatosti za vysokých teplot a studiem vlivu velikosti zkušebního tělesa na měřené hodnoty při využití miniaturních CT těles. Pro účely experimentální práce byla z oceli P91 vyrobena zkušební tělesa standardní a čtvrtinové velikosti. J-R křivky …
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Bulk Ceramic-Based Biologically Inspired Composites: Design, Fabrication and Testing
… and energy absorption. We further show that the curved prism motifs in the proximal parts of the Ostrea edulis shells result in a significant reduction in mechanical robustness due to the growth-related restrictions arising from the simultaneous normal and lateral growth of shells. Moreover, we …