1,721,057 research outputs found
Analytical modelling of pseudo-ductility in angle-ply CFRP laminates with central unidirectional plies
No full textA new analytical modelling method is developed and subsequently used to predict the pseudo-ductile, metal-like stress-strain responses of thin ply CFRP [±θ=0]s laminates. Three combinations of thin ply materials containing standard (235 GPa) and high (540 GPa, 720 GPa, 780 GPa) modulus fibres have been utilised. The modelling method is used to determine the range of ±θ values for each material combination that will exhibit pseudo-ductility. It is shown that a high modulus 0º ply and standard modulus ±θ layers can produce considerable pseudo-ductility, via fragmentation of the 0º ply and local delaminations at the 0/-θ interfaces. With the use of the various thin ply materials and a range of ±θ angles between 20º–30º, the stress-strain response of these laminates can be finely controlled to achieve a desired ‘yield’ stress plateau, pseudo-ductile strain or laminate strength
A simple and robust approach for visual overload indication - UD thin-ply hybrid composite sensors
Get PDFA novel, purpose-designed, thin interlayer glass/carbon-epoxy hybrid composite sensor concept is presented here that can be used for structural health monitoring (SHM), offering potential for safer operation in service. The hybrid composite sensors indicate the overload of a structure by exhibiting a change in their appearance when loaded in tension over a predefined strain value. The sensors can be attached to a component either as a structural sensing layer or integrated locally as demonstrated in this study through real-life applications. Furthermore, various test methods have been utilised to characterise the bonded-on sensors including mechanical testing, Digital Image Correlation (DIC) and Acoustic Emission (AE) measurements. An optimal configuration has been identified with the utilised materials that can potentially be used in applications such as sporting goods, civil engineering structures (e.g. truss and bridge elements) as well as pressure vessels
Taking advantage of the hybrid effect in thin-ply pseudo-ductile laminates: 17th European Conference on Composite Materials, ECCM 2016
No full textHybrid laminates and angle-ply laminates with thin unidirectional carbon plies have been shown to give a pseudo-ductile response with more gradual failure than conventional composites. This paper shows the effect of ply thickness on tensile strength. Significant enhancements to the failure strain are demonstrated in glass-carbon hybrid composites, in hybrids with different grades of carbon fibre and in carbon fibre laminates combining 0° and angle plies. In addition to providing pseudo-ductility, these laminates therefore enable greater advantage to be taken of the intrinsic properties of the materials
Role of fibre fragmentation on pseudo-ductility of thin-ply [±27<sub>7</sub>/0]<sub>s</sub> carbon fibre laminates with high modulus 0° plies under compressive and flexural loading
No full textPseudo-ductile tensile, compressive and flexural behaviour was achieved in a thin-ply carbon fibre [±277/0]s laminate with different fibre types in the angle plies and 0° plies. The laminate with the present layup was tested in both tension and compression, the latter through an unconventional indirect compressive test method using a sandwich beam configuration and the compressive stress was derived by considering the change in position of the neutral axis. The tests demonstrated for the first time that pseudo-ductility and progressive failure can be obtained under compressive loading on thin-ply [±θm/0n]s laminates using a combination of intermediate modulus and high modulus fibre prepregs. Delamination was suppressed throughout the testing and only occurred at the final fracture of the angle plies. Multiple fibre fractures of the 0° plies were obtained within the laminate with the support of the surrounding angle plies in both loading cases. When the laminate was subjected to monolithic flexure, a gradual failure and significant amount of non-linearity occurred. This was primarily due to 0° ply fragmentation on both the compressive and tensile sides of the beam; the fragmentation on both sides resulted in shifts of the neutral axis, retarding the strain increase on the compressive side, delaying the final failure and achieving a higher failure strain in flexure than in compression
A pseudo ductile angle-ply sub-laminate approach for multidirectional thin ply CFRP laminates: 17th European Conference on Composite Materials, ECCM 2016
No full textAnalytical modelling of thin ply angle-ply [±θ/0]s carbon-epoxy layups consisting of intermediate modulus MR60 and ultra high modulus YSH70A prepreg materials has been conducted to establish a candidate configuration for use as a pseudo-ductile sub-laminate in a multidirectional laminate. These layups have demonstrated considerable pseudo-ductility via gradual failure of the 0° ply. Stress-strain predictions of [±25/0]s, in particular, have shown that this layup possesses a high initial modulus of 135 GPa and produce a pseudo-ductile strain of 1.43%, for a strength of 761 MPa. Selected as a sub-laminate configuration, this layup has been applied to two stacking sequences: [30/0/ - 30]s and [45/0/ - 45]s, where the global orientations correspond to the direction of the 0° ply in each sub-laminate. Classical laminate analysis indicates that these multidirectional laminates can exploit the pseudo-ductility of the sub-laminates to achieve a gradual failure at a higher scale
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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