This research investigates whether the layup order of the carbon-fibre/glass-fibre skins in hybrid composite sandwich panels has an effect on impact response. Composite sandwich panels with ...carbon-fibre/glass-fibre hybrid skins were subjected to impact at velocities of 75 ± 3 and 90 ± 3 m s
−1
. Measurements of the sandwich panels were made using high-speed 3D digital image correlation (DIC), and post-impact damage was assessed by sectioning the sandwich panels. It was concluded that the introduction of glass-fibre layers into carbon-fibre laminate skins reduces brittle failure compared to a sandwich panel with carbon-fibre reinforced polymer skins alone. Furthermore, if the impact surface is known, it would be beneficial to select an asymmetrical panel such as Hybrid-(GCFGC) utilising glass-fibre layers in compression and carbon-fibre layers in tension. This hybrid sandwich panel achieves a specific deflection of 0.322 mm kg
−1
m
2
and specific strain of 0.077% kg
−1
m
2
under an impact velocity of 75 ± 3 m s
−1
. However, if the impact surface is not known, selection of a panel with a symmetric yet more dispersed hybridisation would be effective. By distributing the different fibre layers more evenly within the skin, less surface and core damage is achieved. The distributed hybrid investigated in this research, Hybrid-(GCGFGCG), achieved a specific deflection of 0.394 mm kg
−1
m
2
and specific strain of 0.085% kg
−1
m
2
under an impact velocity of 75 ± 3 m s
−1
. Blast loading was performed on a large scale version of Hybrid-(GCFGC) and it exhibited a maximum deflection of 75 mm following a similar deflection profile to those observed for the impact experiments.
The rate-dependent failure response of multi-material adhesive joints for three deformation modes is investigated. A combination of carbon fibre reinforced polymers (CFRP) and titanium alloy ...Ti-6Al-4V is employed. The experiments provide important information about the failure sequence of a multi-material adhesive joints, which depends upon the loading rate regime. This is the first time that dynamic fracture mechanics experiments are performed in multi-material adhesive structures. The observed experimental results suggest a rate-dependent failure sequence for mode I dominated fracture. Simulations of the experiments are used to predict and rationalise the failure performance of the multi-material adhesive joint. The numerical analysis highlighted the importance of the individual knowledge of the rate-dependent mechanical performance of adhesive and composite to fully understand the fracture sequence of multi-material joints under impact.
The development of composite materials through hybridisation is receiving a lot of interest; due to the multiple benefits, this may bring to many industries. These benefits include decreased brittle ...behaviour, which is an inherent weakness for composite materials, and the enhancement of mechanical properties due to the hybrid effect, such as tensile and flexural strength. The effect of implementing hybrid composites as skins on composite sandwich panels is not well understood under high strain rate loading, including blast loading. This paper investigates the blast resilience of two types of hybrid composite sandwich panel against a full-scale explosive charge. Two hybrid composite sandwich panels were mounted at a 15 m stand-off distance from a 100 kg nitromethane charge. The samples were designed to reveal whether the fabric layup order of the skins influences blast response. Deflection of the sandwich panels was recorded using high-speed 3D digital image correlation (DIC) during the blast. It was concluded that the combination of glass-fibre reinforced polymer (GFRP) and carbon-fibre reinforced polymer (CFRP) layers in hybrid laminate skins of sandwich panels decreases the normalised deflection compared to both GFRP and CFRP panels by up to 41 and 23%, respectively. The position of the glass-fibre and carbon-fibre layers does not appear to affect the sandwich panel deflection and strain. A finite element model has successfully been developed to predict the elastic response of a hybrid panel under air blast loading. The difference between the maximum central displacement of the experimental data and numerical simulation was ca. 5% for the hybrid panel evaluated.
By 2020, European Union Member States should achieve Good Environmental Status (GES) for eleven environmental quality descriptors for their marine waters to fulfill the Marine Strategy Framework ...Directive (MSFD). By the end of 2015, in coordination with the Regional Seas Conventions, each EU Member States was required to develop a marine strategy for their waters, together with other countries within the same marine region or sub-region. Coherent monitoring programs, submitted in 2014, form a key component of this strategy, which then aimed to lead to a Program of Measures (submitted in 2015). The European DEVOTES FP7 project has produced and interrogated a catalogue of EU marine monitoring related to MSFD descriptors 1 (biological diversity), 2 (non-indigenous species), 4 (food webs) and 6 (seafloor integrity). Here we detail the monitoring activity at the regional and sub-regional level for these descriptors, as well as for 11 biodiversity components, 22 habitats and the 37 anthropogenic pressures addressed. The metadata collated for existing European monitoring networks were subject to a SWOT (strengths, weaknesses, opportunities and threats) analysis. This interrogation has indicated case studies to address the following questions: a) what are the types of monitoring currently in place?; b) who does what and how?; c) is the monitoring fit-for-purpose for addressing the MSFD requirements?, and d) what are the impediments to better monitoring (e.g. costs, shared responsibilities between countries, overlaps, co-ordination)? We recommend the future means, to overcome the identified impediments and develop more robust monitoring strategies and as such the results are especially relevant to implementing coordinated monitoring networks throughout Europe, for marine policy makers, government agencies and regulatory bodies. It is emphasized that while many of the recommendations given here require better, more extensive and perhaps more costly monitoring, this is required to avoid any legal challenges to the assessments or to bodies and industries accused of causing a deterioration in marine quality. More importantly the monitoring is required to demonstrate the efficacy of management measures employed. Furthermore, given the similarity in marine management approaches in other developed systems, we consider that the recommendations are also of relevance to other regimes worldwide.
Benthic infaunal species and communities have been extensively used to evaluate quality of the marine environment. Within the MSFD, community composition is addressed most commonly through Descriptor ...6 (Seafloor integrity), criterion 6.2 (Condition of benthic communities). At the same time, the Directive has stipulations for addressing and assessing indicators linked with pressures in an explicitly spatial manner. At larger scales, achieving this through point sampling may be impractical or unfeasible; hence predictive methods are being increasingly employed to produce the large scale spatial data that are often required for marine spatial planning and management. The aim of the current work was to develop statistical and spatial modelling tools that can predict the distribution of soft-sediment benthic polychaetes in the Aegean coast of Turkey. To do that, we employed Species Archetype Models (SAMs), a novel analytical and modelling framework which uses mixture models to cluster species responses to the environment, producing a number of “archetypal” responses assumed to represent species with similar ecological/physiological tolerances. Polychaete presence/absence data were obtained from the literature and modelling was performed against environmental variables reflecting the main natural and anthropogenic gradients in the region. The resulting models are interpreted in light of the sensitivity/tolerance classification scheme for benthic invertebrates. Three Species Archetypes were identified through the analysis. In brief, Species Archetype 1 consists of the most prevalent species in the dataset and primarily follows the salinity and temperature gradients. Species Archetype 2, present in the central and southern Aegean, is dominated by sensitive and indifferent species and responds negatively to chlorophyll a, whereas Species Archetype 3 represents mostly tolerant and opportunistic polychaetes with increased probability of occurrence in eutrophic, shallow, inshore areas throughout the region. Predictive performance was constrained by the information contained in our data. These results from a limited data set show promise that SAMs as a modelling tool can offer valuable insights into patterns of benthic species distribution and coexistence and increase our capacity to provide predictive advice.
Pour analyser la situation actuelle en Turquie, et notamment pour caractériser le régime politico-juridique, le professeur Kabo lu propose deux concepts : la déconstitutionnalisation et la ...délégalisation. Cet entretien cherche à décrypter ces deux concepts et à analyser l’évolution de la dégénérescence du régime juridique à des fins politiques. L’entretien révèle aussi comment la période actuelle se différencie d’un passé où les dérives et pratiques antidémocratiques ont toujours existé. Le débat s’ouvre sur les moyens d’une reconstitutionnalisation du régime juridique en Turquie.
Une loi de 2001 créait un Conseil consultatif des droits de l'homme en Turquie. Ce Conseil se réunit pour la première fois en 2003, mais son président, l'auteur de l'article, et un autre membre ont ...été l'objet d'une poursuite pénale en 2005 (pour atteinte à l'" unité nationale ") et le Conseil a été suspendu. C'est le rapport relatif aux droits des minorités et aux droits culturels qui est à l'origine des poursuites pénales. Et elles se situent dans un contexte de remontée d'un nationalisme violent et d'un recul de la liberté d'expression. Reproduced by permission of Bibliothèque de Sciences Po
Le présent article aborde les bouleversements politico-constitutionnels auxquels on a assisté en Turquie à partir du 15 juillet 2016. Alors que l’état d’urgence a été proclamé afin de rétablir ...l’ordre public troublé par la tentative du coup d’état militaire, une modification constitutionnelle visant à la suppression du régime parlementaire a été effectuée dans les circonstances exceptionnelles. Dans cet article, on s’interroge d’abord sur la pratique de l’état d’urgence proclamé dans le cadre constitutionnel et encadré par la Constitution et la Convention européenne des droits de l’homme. Ensuite, la modification constitutionnelle (tellement radicale) dans la continuité de l’ordre constitutionnel est examinée aussi bien du point de vue du temps et de la procédure que des exigences de l’Etat de droit. On se demande enfin si le « nouvel ordre » ! est soutenable dans une organisation politique conçue comme un Etat de droit démocratique basé sur les droits de l’homme.
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