145 resultados para fracture thresholds


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A study on the effect of material and fracture properties of phenolic composites cured with reduced thermal cycle times. These reductions were achieved using various techniques. The work highlights significant reductions in manufacturing times are possible for this group of materials and conveniently can also lead to improved properties.

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This paper is concerned with the construction of fracture envelopes of DP780 sheets using two methods: a hybrid experimental-numerical method; two-dimensional digital image correlation (2D-DIC). For the hybrid method, four types of ductile fracture tests were carried out covering a wide range of stress states on specimens: with a central hole; two symmetric circular notches; flat grooved; and diagonally double-notched. Based on the fracture strain and loading paths identified with finite element simulation, a fracture envelope was obtained by employing the three-parameter modified Mohr-Coulomb fracture model. In addition, the fracture surface strain was directly measured using 2D-DIC. Loading histories of each test were extracted from a surface element of a three dimensional finite element model. The comparison of fracture envelopes constructed by the two methods reveals that there is little difference. Thus, it can be concluded that 2D-DIC is applicable to fracture modelling of DP780 sheets despite the assumption of the plane stress condition even after necking

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Oral chemoreception of fatty acids and the association with diet and fatty food preferences may enable the identification of mechanisms involved with the development of obesity and why dietary changes may be difficult for many individuals.

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This paper considered the charitable ambassador role sports celebrities assume. The research analysed the media attention and the impact on organisations when celebrities transgressed.

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Background: Several studies support the use of CT for diagnosing coronal fractures of the distal radius but the inter-observer reliability of these observations is less well studied. We tested the null hypothesis that radiographs alone and the combination of radiographs and two-dimensional computed tomography scans (2DCT) have the same inter-observer variation for the diagnosis of coronal articular fracture lines in the distal radius. Methods: Using a web-based survey, 63 surgeons were randomized to evaluate 16 fractures of the distal radius on radiographs alone or radiographs and 2DCT for the presence or absence of a coronal fracture line of the lunate facet and, if present, the stability of the fracture. The kappa multirater measure was calculated to estimate agreement between observers. Results: The inter-observer variation in diagnosis of a coronal fracture line was fair with both radiographs and 2DCT, as was the diagnosis of instability of the volar lunate facet fracture when present. Conclusion: Two-dimensional computed tomography does not improve observer agreement on the diagnosis of coronal plane articular fracture lines in the lunate facet of the distal radius. © 2012 American Association for Hand Surgery.

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This study investigated the influence of prior fracture on the risk of subsequent fracture. There was a higher risk of subsequent fracture in both young and older adult age groups when Australian males or females had already sustained a prior fracture. Fracture prevention is important throughout life for both sexes.