Étude de l'effet de la structure sur le comportement mécanique et l'activité acoustique des tubes filamentaire fibre de verre E/vinylester à ±55° par des essais de traction sur anneaux (Split Disk Test (SDT))

L’émission acoustique est l’une des techniques de contrôle non destructif les plus innovatrices qui permet de suivre en temps réel l’endommagement des matériaux composite. Dans cette étude, l’influence de la variation de la structure (tubes avec deux couches : couche anticorrosion (AC) et couche mécanique (CM) et tubes avec CM seulement, avec variation de l’épaisseur de cette couche) sur le comportement mécanique et sur l’activité acoustique des tubes obtenus par enroulement filamentaire par des essais de traction sur anneaux (Spilt Disk Test SDT) a été étudiée. Des anneaux seront préparés et coupés à partir de ces tubes. Un dispositif à été conçu et réalisé spécialement pour cette étude. les essais seront effectués en suivant les instruction de la norme ASTM-2290 Les résultats obtenus ont montré que le comportement mécanique ainsi que l’activité acoustique des tubes filamentaire changent pour chaque type de structure étudiée

Caractérisation mécanique et étude numérique des tubes composites à enroulement filamentaires ±55° assemblés par collage sous chargement uniaxial

Le collage des tubes composites obtenus par le procédé d'enroulement filamentaires semble être technique d'assemblage la plus efficace pour ces structures tubulaires. Une telle technique représente de nombreux avantages par rapports aux autres techniques (boulonnage, rivetage). Cependant, la compréhension des mécanismes d'endommagement de ces structures assemblées est peu maitrisée, ce qui rend leur utilisation moins fréquente dans plusieurs domaines. Dans ce travail, une étude expérimentale a été menée afin de caractériser le comportement mécanique en traction des tubes composites à base de fibres de verre de type E et trois types de résines (Vinylester, Vinylester 470 et Polyester Isophtalique) assemblés par collage en utilisant la colle Araldite. Egalement le comportement mécanique de cette colle a été analysé à travers des essais de traction uniaxial. Une étude numérique a été menée afin de mieux prédire le comportement élastique des ces tubes

Experimental and numerical study of adhesively bonded\textpm55° filament wound tubular specimens under uniaxial tensile loading

International audienceThis work denotes an insight into an experimental and numerical investigation of adhesively bonded tubular specimens. A series of tensile tests have been conducted on joined E glass reinforced thermoset resins to study the effect of the resin nature on mechanical behaviour. It has been proved through experimental outcomes that E glass/Vinylester 411 resin tube presents the best tensile properties in comparison with others resins. Therefore, the mechanical behaviour of this specimen has been investigated under uniaxial loading. The damage mechanisms resulting from this experimental test have been identified by means of the X-ray tomography and scanning electron microscope. A numerical model has been undertaken in order to predict the mechanical behaviour and the damage propagation of adhesively bonded tubular specimens. It has been proved that experimental and numerical results are in perfect agreement

Modeling and multi-objective optimization of abrasive water jet machining process of composite laminates using a hybrid approach based on neural networks and metaheuristic algorithm

International audienceAlthough the abrasive water jet (AWJ) has proven to be a suitable process for machining composite materials, it has some limitations related to dimensional inaccuracy and surface defects. As the performance of the AWJ process mainly depends on the machining parameters, an optimal selection of them is crucial to achieving an improved quality of cut. In this context, the present study reports an experimental investigation to assess the influence of AWJ machining parameters on kerf taper angle (θ) and surface roughness ( R a ) of E glass/Vinylester 411 resin laminates. The experiments are carried out using a full factorial design by varying the water pressure, traverse speed, abrasive flow rate, and standoff distance. A first-ever attempt is made in this paper to optimize the AWJ process using a hybrid approach combining artificial neural networks (ANNs) with a recently proposed metaheuristic algorithm known as multi-objective bonobo optimizer (MOBO). The results show that standoff distance and abrasive flow rate were the most significant control factors in influencing θ and R a , respectively. The developed ANN models are capable to predict the output responses with high accuracy and the solutions from the Pareto front provide a sufficient performance with a trade-off between θ and R a . The corresponding levels of the optimal process parameters are 430 g/min for the abrasive flow rate, the range of 140–180 mm/min for the traverse speed, 280 MPa for the pressure, and 1.5 mm for the standoff distance

Fire behaviour of hybrid filament-wound single and adhesively bonded composites tubes under static pressure

International audienceThe present work aims to experimentally investigate the fire behaviour of water-filled E glass reinforced thermoset resin hybrid filament-wound composites tubes under static pressure. Heretofore, fire endurance tests have been conducted on single and adhesively bonded tubes manufactured by CTRA Company. Furthermore, internal pressure tests until failure have been performed on the burnt single and burnt joined tubes in order to quantify their abilities to contain the fluid after being exposed to heat flux. A comparison between the pressure behaviour of exposed to fire (burnt) and non-exposed tubes (single and joined) was also inspected. The identification of the fire-induced damage mechanisms of the tubes was performed through optical microscopy, Scanning Electron Microscopy (SEM) and X-ray tomographic observations. Finally, the thermal analysis was carried-out on burnt specimens in order to better understand the multiphysical phenomenon taking place during the fire endurance tests. The experimental results have revealed that the combustion process of both single and joined tubes was described in four steps namely tube heating, resin degradation, ignition and flame decay. Moreover, it was found that no leakage was witnessed on the tubes (single and joined) outer surfaces during the fire endurance tests. The comparison between the pressure behaviour of the burnt single tube and the burnt joined one has proved that the single tube is much resistant under internal pressure loading than the burnt joined tube. Finally, the fire-induced damage included matrix cracking and delamination between the tube plies which was noticed from microscopic observations

Experimental investigation of three-point bending behavior of assembled hybrid composite tubes before and after the fire endurance test

International audienceThis work presents an experimental investigation of the post-fire flexural strength of Filament-wound Glass Fiber Reinforced Polymer (GFRP) tubes manufactured by CTRA Company. These tubes are assembled according to both the NFT57-900 and DIN-16966 standards’ recommendations. To this end, flexural tests have been carried out on butt-to-butt assembled tubes, before and after fire endurance tests. To gain a better insight into fire-induced damage mechanisms, thermal analysis (DSC and TGA), FTIR analysis tests, as well as Scanning Electron Microscope (SEM) observations have been conducted. The experimental results revealed that a water leakage was observed prior to the recommended threshold time by the International Maritime Organization (IMO) resolution. It has been also confirmed that flexural properties of the GFRP tube are degraded after the fire tests. Furthermore, a quantitative comparison for both filament tubes assembled according to the NFT and DIN standards confirms that the NFT ones depict higher resistance. Finally, damage investigation reveals that the main observed forms of damage occurring during this experiments are delamination and matrix cracking phenomena. The main novelties of this work are (a) extending the classic analysis carried out on simple composite plate to cover water-filled GFRP assembled tubes subject to fire endurance test, and (b) the experimental investigation of DIN and NFT butt welded joined pipes under three point loading prior and post fire endurance test

Experimental investigation of single and butt-welded GFRP filament winding tubes bending behavior based on conventional and Digital Image Correlation method

International audienceComposite joints have become increasingly popular in pipeline assembly, replacing conventional fasteners. However, butt-welded joint composite techniques still need further structural study. This paper aims to study the flexural mechanical performance of the above mentioned composite joint method. Four-point bending tests were conducted on both unassembled (single) and two butt-welded tube types (based on NFT and DIN standard methods). In this context, the 2D digital image correlation (DIC) technique was applied during these tests to analyze the damage scenario based on full-field strain mapping. To further visualize the microscopic damage modes, X-ray tomography observations were conducted on both single and butt-welded specimens. The experimental results show that single tubes have the highest mechanical properties, with quasi-elastic behavior until the occurrence of fracture. The NFT butt-welded composite tubes present the maximum flexural stiffness and strength compared with the DIN tubes. It has also been shown that the strain distribution depends on the specimen configuration. The DIC analysis results show that the damage scenario is divided into two events: the onset of fracture and then the fracture propagation. These results were confirmed through microscopic inspections. © 2023 Elsevier Lt