1,138 research outputs found
A shallow crack assessment scheme for generalised material behaviour in pure bending
No full textAn engineering J-integral estimation procedure has been developed from data generated using finite element computations. The study has been focused on shallow edge cracked geometries with crack depths up to 10% of the specimen depth and subjected to severe localised plastic deformation under pure bending loading. The material behaviour considered is of a generalised nature—one that consists of a perfectly plastic plateau preceding the work hardening region, which is represented by power law. J-estimation equations were developed from curve-fitting a large number of J versus remote strain curves obtained from finite element analyses. The validity of the proposed scheme was confirmed by comparison with finite element solutions on specimens with fictitious and real material curves. The current work, together with a previously presented scheme for tension loading, hence provides a comprehensive treatment of defect assessment of shallow cracked geometries under severe localised plastic deformation.<br/
The effects of weld mismatch on J-integrals and Q-values for semi-elliptical surface flaws
No full textThree-dimensional finite element analysis of shallow semi-elliptical surface flaws in the centre of rectangular welds was undertaken, and the effects of varying weld mismatch and weld width on J-integrals and Q-values were investigated. An interesting relationship between weld width and the applied load at failure, as predicted from a J–Q failure locus, was observed. The practicalities of modifying the J- and Q-estimation schemes developed for homogeneous plates to include mismatch effects were investigated using a limited parametric study
The sensitivity of J-integrals to material law variations for semi-elliptical surface cracks
No full textJ estimation for shallow semi-elliptical surface cracks in wide plates under pure bending
No full textThree-dimensional finite element models have been used to predict the J versus applied strain behaviour of shallow semi-elliptical surface cracks in wide steel plates. These models were loaded in pure bending up to fully plastic conditions that produced maximum strains remote from the crack of 10 times the yield strain. This study examined cracks with a crack depth to plate thickness ratio (a/t) in the range 0.05–0.15, and crack depth to crack half-length ratio (a/c) from 0.2 to 0.57, in elastic-hardening materials as well as those with a yield plateau before strain-hardening. The results were found to differ significantly from those obtained from plane strain analyses, and a J estimation scheme was developed from the three-dimensional results. Comparisons between the results obtained in this work and the J predictions provided by existing defect assessment methods show that the proposed equations are a significant improvement when large strains are likely.<br/
Effects of biaxial loading on crack driving force and constraints in shallow semi-elliptical surface flaws
No full textThree-dimensional, elastic-plastic finite element analyses have been carried out to investigate the effects of biaxial loading on J-integrals and Q-values for shallow semi-elliptical surface flaws in wide plates. Direct tension and pure bending loading of up to about 10 times the yield strain were applied to models with linear elastic-power hardening and tripartite material behaviours. Crack depths were limited to 15 percent of the plate thickness. Differences were observed between the effects of biaxiality on J-strain behaviour for cracks in semi-infinite plates and those in finite width plates. The cracked semi-infinite geometry was considered more representative of structural applications. In this case, biaxial loading gave a large increase in J-integrals compared to uniaxial loading, but had negligible effect on constraint, as measured using the Q-value
J-estimation for semi-elliptical surface cracks in wide plates under direct tension
No full textLarge marine structures can be subjected to extensive localized damage, with strains reaching 10 times the yield strain. Small defects might propagate, and accurate defect assessment is required for safe operation. To simulate this problem, J-integrals have been computed for semielliptical cracks in wide steel plates under tension. Three-dimensional (3D) elastic–plastic finite element analysis was used to model shallow crack geometries with 0.2???a/c???0.57 and 0.05???a/t???0.15. The material responses were linear elastic followed either by power hardening, or perfect plasticity and power hardening. It was found that, in contrast to previous studies on single edge notch geometries, the material law does not have a major influence on the J–strain behaviour. Results obtained from the 3D analyses form the basis for the development of a J-based estimation scheme.<br/
New exact coherent states in channel flow
No full textThree spatially periodic travelling wave exact coherent states are presented for channel flow. Two of the flows, which are asymmetric with respect to the channel centreplane, are derived by homotopy from solutions for channel flow subject to a spanwise rotation investigated by [1]. The third flow satisfies a half-turn rotational symmetry about a point on the channel centreplane, and turns out to be the flow from which one of the asymmetric flows bifurcates in a symmetry breaking bifurcation. One of the asymmetric flows is found to substantially reduce the value of the lowest Reynolds number at which exact solutions are known to exist down to 665
Scouts & Guides - Latvians WWII
No full textA detailed description (including locations, dates and Troup No.'s) where Boy Scouts and Girl Guides were present during WWII and Post WWII (including Troup numbers)6.0 Documents, 3.0 The War Years, 3.1.9 D.P. Camps, 10.0 Life of Latvian Children, 10.1.4 Boy Scouts and Girl Guide
Author Correction:A 41,500 year-old decorated ivory pendant from Stajnia Cave (Poland)
No full textCorrection to: Scientific Reports https://doi.org/10.1038/s41598-021-01221-6, published online 25 November 2021The original version of this Article contained errors in the author list where Marjolein D. Bosch was omitted from the author list, and Mikołaj Urbanowski was incorrectly listed as an author of the original Article, and has subsequently been removed.The Author contributions section now reads:“S.T. W.N. and A.N. conceived the project; S.T., W.N., A.P., M.B., S.C., M.D., H.F., A.M., M.D. B., D.P., M.P.R., C.M.R., V.S-M., G.M.S., P.S., M.S., K.S., A.V., F.W., H.W., A.W., M.Z., S.B., A.N., J-J. H., performed research; S.T., A.P., W.N., M.B., M.D.B., S.C., M.D., H.F., A.M., D.P., M.P.R., C.M.R., V.S-M., G.M.S., P.S., M.S., K.S., A.V., F.W., H.W., A.W., M.Z., S.B., A.N., J-J. H. analysed all archaeological data; S.T. and A.P. wrote the paper with the collaboration of all the co-authors.”The original Article and its accompanying Supplementary Information file have been corrected
Perryvale School District No. 4390 - 03
No full textPhotograph - Staff members at Perryvale School, left to right: D.P. Walsh and left to right, Anne Lehto and Eleanor Telford, Perryvale, AlbertaWalsh, D.P; Lehto, Anne; Telford, Eleano
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