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| Registros recuperados: 131 | |
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| Le Gac, Pierre-yves; Davies, Peter; Choqueuse, Dominique. |
| Polymers and composites are very attractive for underwater applications, but it is essential to evaluate their long term behaviour in sea water if structural integrity of offshore structures is to be guaranteed. Accelerated test procedures are frequently required, and this paper will present three examples showing how the durability of polymers, in the form of fibres, matrix resins in fibre reinforced composites for structural elements, and thermal insulation coatings of flow-lines, have been evaluated for offshore use. The influence of the ageing medium, temperature, and hydrostatic pressure will be discussed first, then an example of the application of ageing test results to predict long term behavior of the thermal insulation coating of a flowline will... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00199/30978/29356.pdf |
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| Floreani, Christophe; Robert, Colin; Alam, Parvez; Davies, Peter; Ó. Brádaigh, Conchúr M.. |
| Powder epoxy composites have several advantages for the processing of large composite structures, including low exotherm, viscosity and material cost, as well as the ability to carry out separate melting and curing operations. This work studies the mode I and mixed-mode toughness, as well as the in-plane mechanical properties of unidirectional stitched glass and carbon fibre reinforced powder epoxy composites. The interlaminar fracture toughness is studied in pure mode I by performing Double Cantilever Beam tests and at 25% mode II, 50% mode II and 75% mode II by performing Mixed Mode Bending testing according to the ASTM D5528-13 test standard. The tensile and compressive properties are comparable to that of standard epoxy composites but both the mode I... |
| Tipo: Text |
Palavras-chave: Toughened composites; Fracture toughness; Delamination. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00692/80371/83488.pdf |
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| Davies, Peter; Sims, Gd; Blackman, Brk; Brunner, Aj; Kageyama, K; Hojo, M; Tanaka, K; Murri, G; Rousseau, C.; Gieseke, B; Martin, Rh. |
| This paper presents a summary of the tests performed within a Versailles Project on Advanced Materials and Standards collaborative test programme to examine the measurement of mode II interlaminar fracture toughness using four different test methods based on end notched flexure, stabilised end notched flexure, end loaded split, and four point end notched flexure carbon fibre reinforced epoxy specimens. Tests were performed by members of the European Structural Integrity Society, the Japan Industrial Standards group, and the American Society for Testing and Materials. PRC/1546 |
| Tipo: Text |
Palavras-chave: Delamination; Fracture tests; Mode II; Interlaminar shear; Fracture toughness. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00148/25883/24089.pdf |
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| Cognard, J. Y.; Creac'Hcadec, R.; Da Silva, L. F. M.; Teixeira, F. G.; Davies, Peter; Peleau, Michel. |
| The modelling of the non-linear behaviour of ductile adhesives requires a large experimental database in order to represent accurately the strains which are strongly dependent on the tensile-shear loading combination. Various pressure-dependent constitutive models can be found in the literature, but only a few experimental results are available, for instance, to represent accurately the initial yield surface taking into account the two stress invariants, hydrostatic stress, and von Mises equivalent stress. This paper presents the possibility of combining the use of tests on bulk specimens and tests on bonded assemblies, which strongly limit the influence of the edge effects, with a pressure vessel especially designed to study the influence of hydrostatic... |
| Tipo: Text |
Palavras-chave: Adhesive testing; Finite element analysis; Hydrostatic stress; Modelling; Non-linear behaviour; Yield surface. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00048/15917/13374.pdf |
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| Khalid, Faryal; Davies, Peter; Halswell, Peter; Lacotte, Nicolas; Thies, Philipp R.; Johanning, Lars. |
| Innovation in materials and test protocols, as well as physical and numerical investigations, is required to address the technical challenges arising due to the novel application of components from conventional industries to the marine renewable energy (MRE) industry. Synthetic fibre ropes, widely used for offshore station-keeping, have potential application in the MRE industry to reduce peak mooring line loads. This paper presents the results of a physical characterisation study of a novel hybrid polyester-polyolefin rope for MRE mooring applications through a round robin testing (RRT) approach at two test facilities. The RRT was performed using standard guidelines for offshore mooring lines and the results are verified through the numerical modelling of... |
| Tipo: Text |
Palavras-chave: Synthetic fibre ropes; Testing infrastructure; Round robin testing; Rope modelling; Mooring components; Marine renewable energy. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00634/74605/74493.pdf |
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| Le Duigou, Antoine; Merotte, Justin; Bourmaud, Alain; Davies, Peter; Belhouli, Karim; Baley, Christophe. |
| The present article aims to investigate the contribution of hygroscopic expansion of flax fibres to interfacial radial stresses and Interfacial Shear Strength (IFSS) of Maleic Anhydride grafted PolyPropylene (MAPP)/Flax biocomposites. During manufacturing of thermoplastic biocomposites and storage at 50% RH, a weight variation is observed, attributed to water content evolution within plant cell-walls. The hygroscopic radial expansion coefficient βr flax of single flax fibres estimated by Environmental Scanning Electron Microscopy (ESEM) observation is many orders of magnitude higher (βf,R = 1.14 ε/Δm) than thermal expansion (αf, R = 78 10−6 ε/°C). Thus, its contribution to the development of residual stresses σrad during processing should be prevalent. A... |
| Tipo: Text |
Palavras-chave: Flax fibres; Fibre/matrix bond. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00397/50830/51594.pdf |
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| Stamoulis, Georgios; Carrere, Nicolas; Cognard, J. Y.; Davies, Peter; Badulescu, Claudiu. |
| The use of adhesively bonded structures is widespread in various engineering fields, as they provide many advantages over other conventional types of mechanical joints. In this study, we use a crash optimized, single-component epoxy adhesive (SikaPower®-498 made of a rigid epoxy matrix containing soft, tough polymer inclusions that provide additional ductility to the adhesive layer) at a constant layer thickness of 0.5 mm to bond metallic substrates. We investigate its fracture properties under mode I and mixed-mode I/II loadings, in order to obtain the full fracture envelope. Mode I loading has been performed using the ISO 25217 standard: the substrates were designed according to the TDCB (Tapered Double Cantilever Beam) geometry, and the fracture... |
| Tipo: Text |
Palavras-chave: Fracture toughness; Linear Elastic Fracture Mechanics (LEFM); Adhesive bonding; Finite Element Analysis (FEA); Failure criterion. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00181/29273/27685.pdf |
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| Humeau, Corentin; Davies, Peter; Jacquemin, Frederic. |
| The coupling between tensile stress and water diffusion in composites represents a major issue in many marine applications. Even if these two behaviours are well documented as separate subjects, there are still very few data on fully coupled mechanisms. The aim of this study is to understand what governs the coupled behaviour, by investigating the water diffusion in carbon/epoxy. The coupling is first evaluated on neat resin samples to characterise the matrix behaviour. Then the study focuses on composites with two types of woven fibre orientation: one at ±45°, in order to understand the coupling effects on materials loaded away from the reinforcement direction and another quasi-isotropic to obtain properties along the fibres. For each material the same... |
| Tipo: Text |
Palavras-chave: Composite; Moisture diffusion; Static tensile stress; Coupled behaviour. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00416/52788/53687.pdf |
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| Davies, Peter. |
| This paper describes the influence of seawater ageing on composites used in a range of marine structures, from boats to tidal turbines. Accounting for environmental degradation is an essential element in the multi-scale modelling of composite materials but it requires reliable test data input. The traditional approach to account for ageing effects, based on testing samples after immersion for different periods, is evolving towards coupled studies involving strong interactions between water diffusion and mechanical loading. These can provide a more realistic estimation of long-term behaviour but still require some form of acceleration if useful data, for 20 year lifetimes or more, are to be obtained in a reasonable time. In order to validate extrapolations... |
| Tipo: Text |
Palavras-chave: Seawater; Immersion; Durability; Damage; Coupling. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00340/45167/44603.pdf |
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| Carr, Magda; Sutherland, Peter; Haase, Andrea; Evers, Karl‐ulrich; Fer, Ilker; Jensen, Atle; Kalisch, Henrik; Berntsen, Jarle; Părău, Emilian; Thiem, Øyvind; Davies, Peter. |
| Internal solitary waves (ISWs) propagating in a stably stratified two-layer fluid in which the upper boundary condition changes from open water to ice are studied for grease, level, and nilas ice. The ISW-induced current at the surface is capable of transporting the ice in the horizontal direction. In the level ice case, the transport speed of, relatively long ice floes, nondimensionalized by the wave speed is linearly dependent on the length of the ice floe nondimensionalized by the wave length. Measures of turbulent kinetic energy dissipation under the ice are comparable to those at the wave density interface. Moreover, in cases where the ice floe protrudes into the pycnocline, interaction with the ice edge can cause the ISW to break or even be destroyed... |
| Tipo: Text |
Palavras-chave: Internal solitary waves; Sea ice; Arctic Ocean. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00593/70532/68677.pdf |
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| Chailleux, Emmanuel; Davies, Peter. |
| In this study the macroscopic analysis proposed by Schapery has been applied to model the non-linear viscoelastic and viscoplastic behaviour of polyester fibres. First, a special non-contact extensometry method has been developed in order to measure the fibre response without affecting the behaviour of these extremely anisotropic fibres. An accelerated identification method has then been developed. This enables a unique and independent set of parameters to be determined, which separate the reversible and non-reversible mechanisms responsible for measured strains. The model prediction for an arbitrary loading sequence corresponds closely to the measured strains. The model has been applied here at the yarn level but can equally well be used to predict rope... |
| Tipo: Text |
Palavras-chave: Viscoplastic; Viscoelastic; Polyester; Non linear; Model; Fibre. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-794.pdf |
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| Davies, Peter; Francois, M; Lacotte, Nicolas; Vu, Thanh Do; Durville, Damien. |
| Repeated bending over sheaves is one of the main causes of failure of synthetic fibre ropes used in marine operations. There are few published results available and even fewer models allowing lifetime to be estimated. A large new set of data from cyclic bend over sheave (CBOS) tests on 250 kN break load braided HMPE synthetic ropes is presented first, both tests to failure and interrupted tests followed by residual strength measurements. These data are analysed in order to propose an empirical lifetime model. This is identified using constant load tests, then evaluated for variable load sequences. A methodology to include rope lifetime prediction in handling system design is then discussed. |
| Tipo: Text |
Palavras-chave: Fibre rope; Bending; Sheave; Abrasion; Fatigue. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00251/36215/34775.pdf |
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| Baral, N.; Cartie, D. D. R.; Partridge, I. K.; Baley, C.; Davies, Peter. |
| This paper presents results from a test developed to simulate the water impact (slamming) loading of sandwich boat structures. A weighted elastomer ball is dropped from increasing heights onto rigidly supported panels until damage is detected. Results from this test indicate that honeycomb core sandwich panels, the most widely used material for racing yacht hulls, start to damage due to core crushing at impact energies around 550 J. Sandwich panels of the same areal weight and with the same carbon/epoxy facings but using a novel foam core reinforced in the thickness direction with pultruded carbon fibre pins, do not show signs of damage until above 1200 J impact energy. This suggests that these will offer significantly improved resistance to wave impact.... |
| Tipo: Text |
Palavras-chave: Honeycomb; Three-dimensional reinforcement; Impact behaviour; Mechanical testing. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00002/11311/7840.pdf |
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| Ilioni, Alin; Badulescu, C.; Carrere, N.; Davies, Peter; Thevenet, D.. |
| Most of the adhesives used in the marine industry are polymers with a mechanical behaviour which is strongly influenced by the strain rate. Therefore, it is important to predict with accuracy their viscous behaviour. To describe their mechanical behaviour in a bonded joint, a viscoelastic-viscoplastic constitutive law is proposed here. The viscous effects on the elastic behaviour is described using a spectral distribution, which divides the viscous strain as the sum of the strains of several viscous mechanisms, each of them with a different characteristic time and weight. The viscoplastic component of the model permits a better description of the strong non-linear behaviour of the adhesives. The parameters of the constitutive law are obtained using an... |
| Tipo: Text |
Palavras-chave: Epoxides; Mechanical properties of adhesives; Creep / mechanical relaxation. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00415/52651/53507.pdf |
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| Ghoreishi, Seyed Reza; Davies, Peter; Cartraud, Patrice; Messager, Tanguy. |
| In part I of this study it was shown that, to model synthetic fiber ropes, two scale transition models can be used in sequence. The first model (continuum model) has been presented in the part I and the present paper examines the behavior of a fibrous structure consisting of 6 helicoidal strands around a central core (1 + 6 structure). An analytical model will be presented which enables the global elastic behavior of such a cable under tension-torsion loading to be predicted. In this model, first, the core and the strands are described as Kirchhoff-Love beams and then the traction-torsion coupling behavior is taken into account for both of them. By modeling the contact conditions between the strands and the core, with certain assumptions, it is possible to... |
| Tipo: Text |
Palavras-chave: Testing; Analytical model; Aramid; Wire; Simple strand; Fiber rope. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2596.pdf |
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| Registros recuperados: 131 | |
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