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Lars Pejryd - One of the best experts on this subject based on the ideXlab platform.
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dual energy computed tomography investigation of additive manufacturing aluminium Carbon Fibre Composite joints
Heliyon, 2019Co-Authors: Anton Jansson, Lars PejrydAbstract:Abstract In this work, aluminium–Carbon-Fibre reinforced plastic joints have been studied. Three types of samples were designed as double lap joints where the aluminium inserts were fabricated using both classical methods (milling) and additive manufacturing. Two versions of the joint were fabricated using additive manufacturing, one flat, and the other with small teeth designed to hook into the Carbon-Fibre plies. The joints were characterised using a non-linear, dual-energy computed tomography method to evaluate the bond between the Composite and the metal inserts. The mechanical strength of the bonds was evaluated, both through tensile tests and four-point bending. A simple finite element model was used to discuss the joints behaviour. It was found that the joints fabricated using additive manufactured inserts were more resistant to peel stress than the milled inserts. In four-point bending tests the moment that the joint could withstand was increased by roughly 300% with the use of additive manufacturing and 400% with the use of additive manufacturing and small teeth. However, in tensile tests it was found that the teeth design reduced the maximum load capacity of the joints by roughly 30% due to porosity. Further, it was found that the additive manufactured samples did not add to the capability of withstanding shear stress. The information gained with the dual-energy computed tomography method was highly valuable as the behaviour of the joints would have been difficult to explain without the porosity information.
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Dual-energy computed tomography investigation of additive manufacturing aluminium–Carbon-Fibre Composite joints
Elsevier, 2019Co-Authors: Anton Jansson, Lars PejrydAbstract:In this work, aluminium–Carbon-Fibre reinforced plastic joints have been studied. Three types of samples were designed as double lap joints where the aluminium inserts were fabricated using both classical methods (milling) and additive manufacturing. Two versions of the joint were fabricated using additive manufacturing, one flat, and the other with small teeth designed to hook into the Carbon-Fibre plies. The joints were characterised using a non-linear, dual-energy computed tomography method to evaluate the bond between the Composite and the metal inserts. The mechanical strength of the bonds was evaluated, both through tensile tests and four-point bending. A simple finite element model was used to discuss the joints behaviour. It was found that the joints fabricated using additive manufactured inserts were more resistant to peel stress than the milled inserts. In four-point bending tests the moment that the joint could withstand was increased by roughly 300% with the use of additive manufacturing and 400% with the use of additive manufacturing and small teeth. However, in tensile tests it was found that the teeth design reduced the maximum load capacity of the joints by roughly 30% due to porosity. Further, it was found that the additive manufactured samples did not add to the capability of withstanding shear stress. The information gained with the dual-energy computed tomography method was highly valuable as the behaviour of the joints would have been difficult to explain without the porosity information. Keywords: Mechanical engineering, Materials scienc
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characterisation of additive manufacturing metal Carbon Fibre Composite bond by dual energy computed tomography
EUSPEN Conference Proceedings Special Interest Group: Dimensional Accuracy and Surface Finish in Additive Manufacturing Katholieke Universiteit Leuven, 2017Co-Authors: Anton Jansson, Lars PejrydAbstract:Joining of dissimilar materials is a topic of high interest for the industry. The ability to seamlessly join materials with significant differences in properties would advance the development of ef ...
Anthony R Bunsell - One of the best experts on this subject based on the ideXlab platform.
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acoustic emission analysis of Composite pressure vessels under constant and cyclic pressure
Composites Part A-applied Science and Manufacturing, 2015Co-Authors: H Y Chou, M K Bannister, Adrian P. Mouritz, Anthony R BunsellAbstract:The use of acoustic emission (AE) for the detection of damage in Carbon Fibre Composite pressure vessels was evaluated for constant and cyclic internal gas pressure loading conditions. AE was capable of monitoring the initiation and accumulation of damage events in a Composite pressure vessel (CPVs), although it was not possible to reliably distinguish Carbon Fibre breakage from other microscopic damage events (e.g. matrix cracks, Fibre/matrix interfacial cracks). AE tests performed on the Carbon Fibre laminate used as the skin of pressure vessels revealed that the development of damage is highly variable under constant pressure, with large differences in the rupture life and acoustic emission events at final failure. Numerical analysis of the skin laminate under constant tensile stress revealed that the high variability in the stress rupture life is due mainly to the stochastic behaviour of the Carbon Fibre rupture process.
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intrinsic safety factors for glass Carbon Fibre Composite filament wound structures
Applied Composite Materials, 2014Co-Authors: Anthony R Bunsell, Alain Thionnet, H Y ChouAbstract:The determination of intrinsic safety factors for glass and Carbon Fibre unidirectional Composites and filament wound internally pressurised structures, is described. In such structures the Fibres are placed on geodesic paths and the pressure induces tensile forces in them. The Fibres ensure the strength of the Composite and must break for it to fail. Failure is seen in such structures, to depend mainly on the accumulation of Fibre breaks. These are initially randomly distributed but become critical when clusters of breaks develop. Long term behaviour of Carbon Fibre Composites is controlled by the viscoelastic relaxation of the matrix around breaks, which can lead to further delayed Fibre breaks. Failure in glass Fibre structures can additionally be induced by stress corrosion of the glass Fibres. This process does not seem to occur with Carbon Fibres and as the latter are increasingly used in critical structures emphasis is given to them. Until the development of clusters of Fibre breaks, in a filament wound structure, no macroscopic changes in the Composite behaviour are evident so that failure occurs in a sudden death manner. Multi-scale simulation, taking into account the characteristics of the Composite components and scaling up their behaviour under load, accurately describes the overall behaviour of the Composite structure. This approach not only allows the behaviour to be described, as a function of time, but also calculates the scatter which will occur in the behaviour of the structure. This allows the intrinsic safety factors of the Composite structure to be quantified.
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Determination of lifetime probabilities of Carbon Fibre Composite plates and pressure vessels for hydrogen storage
International Journal of Hydrogen Energy, 2011Co-Authors: S. Camara, Anthony R Bunsell, Alain Thionnet, David H. AllenAbstract:It is shown that an analogy can be made between the failure of unidirectional Carbon Fibre reinforced epoxy plates and filament wound Carbon Fibre Composite pressure vessels and that their strengths and failure probabilities can be determined. Fibres in filament wound Composite structures are placed on geodesic paths around the mandrel, which becomes the liner; so that when the structure is pressurised the Fibres are only subjected to tensile forces, as in a unidirectional Composite. Multiscale modelling reveals that Composite failure is controlled by Fibre breakage and that clustering of Fibre breaks determines ultimate reliability of the structure. Time dependent relaxation of the matrix leads to delayed failure of the elastic Fibres. A statistical study, using the stochastic properties of the Fibres, determines the range of lifetimes which will be obtained in a given class of pressure vessel, leading to an evaluation of failure probabilities as a function of internal pressures. In this way the definition of safety factors, based on an understanding of the physical processes governing damage accumulation, becomes possible.
Andreas T Echtermeyer - One of the best experts on this subject based on the ideXlab platform.
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critical energy release rate for a csm reinforced Carbon Fibre Composite steel bonding
Composites Part A-applied Science and Manufacturing, 2006Co-Authors: Hakon W Andresen, Andreas T EchtermeyerAbstract:Abstract Metal structures are usually repaired by welding. An alternative is the bonding of Composite patches, like Carbon Fibre reinforced epoxy, over cracked or corroded sections to restore strength or stiffness. The patch repair method is especially favourable in oil and gas installations, where the sparks from welding create a fire hazard. Knowledge of the adhesive strength of the interface between the dissimilar materials is an essential part in designing and qualifying such repairs. Specimens were made by attaching a Carbon laminate to a steel plate with a glass-Fibre reinforced adhesive. The Double Cantilever Beam test and the End Notched Flexure test were used to measure G IC and G IIC , respectively. G IIC was crack length dependent and the interfaces show some apparent plastic behaviour ahead of the crack. The steel–adhesive interface was found to be the weak link in both failure modes. In contrast to typical laminate properties the critical energy release rate of the interface of this system was higher in Mode I than in Mode II. This behaviour could be explained by looking at the characteristics of the fracture surfaces.
V.s. Deshpande - One of the best experts on this subject based on the ideXlab platform.
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Indentation response of a 3D non-woven Carbon-Fibre Composite
Journal of Materials Research, 2018Co-Authors: Satyajit Das, K. Kandan, Haydn N G Wadley, Sohrab Kazemahvazi, V.s. DeshpandeAbstract:The indentation response of a 3D noninterlaced Composite comprising three sets of orthogonal Carbon-Fibre tows in an epoxy matrix is investigated. The 3D Composites have a near isotropic and ductile indentation response. The deformation mode includes the formation of multiple kinks in the tows aligned with the indentation direction and shearing of the orthogonally oriented tows. Finite element (FE) calculations are also reported wherein tows in one direction are explicitly modeled with the other two sets of orthogonal tows and the matrix pockets treated as an effective homogenous medium. The calculations capture the indentation response in the direction of the explicitly modeled tows with excellent fidelity but under-predict the indentation strength in the other directions. In contrast to anisotropic and brittle laminated Composites, 3D noninterlaced Composites have a near isotropic and ductile indentation response making them strong candidates for application as materials to resist impact loading.
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Compressive response of a 3D non-woven Carbon-Fibre Composite
International Journal of Solids and Structures, 2017Co-Authors: K. Kandan, S. Kazemahvazi, Haydn N G Wadley, V.s. DeshpandeAbstract:The compressive response of a three-dimensional (3D) non-interlaced Composite comprising three orthogonal sets of Carbon Fibre tows within an epoxy matrix is analysed. First, the compressive response is measured in three orthogonal directions and the deformation/failure modes analysed by a combination of X-ray tomography and optical microscopy. In contrast to traditional unidirectional and two-dimensional (2D) Composites, stable and multiple kinks (some of which zig-zag) form in the tows that are aligned with the compression direction. This results in an overall Composite compressive ductility of about 10% for compression in the low Fibre volume fraction direction. While the stress for the formation of the first kink is well predicted by a usual micro-buckling analysis, the Composite displays a subsequent hardening response associated with formation of multiple kinks. Finite element (FE) calculations are also reported to analyse the compressive response with the individual tows modelled as anisotropic continua via a Hill plasticity model. The FE calculations are in good agreement with the measurements including prediction of multiple kinks that reflect from the surfaces of the tows. The FE calculations demonstrate that the three-dimensionality of the microstructure constrains the kinks and this results in the stable compressive response. In fact, the hardening and peak strength of these Composites is not set by the tows in direction of compression, but rather set by the out-of-plane compressive response of the tows perpendicular to the compression direction.
Anton Jansson - One of the best experts on this subject based on the ideXlab platform.
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dual energy computed tomography investigation of additive manufacturing aluminium Carbon Fibre Composite joints
Heliyon, 2019Co-Authors: Anton Jansson, Lars PejrydAbstract:Abstract In this work, aluminium–Carbon-Fibre reinforced plastic joints have been studied. Three types of samples were designed as double lap joints where the aluminium inserts were fabricated using both classical methods (milling) and additive manufacturing. Two versions of the joint were fabricated using additive manufacturing, one flat, and the other with small teeth designed to hook into the Carbon-Fibre plies. The joints were characterised using a non-linear, dual-energy computed tomography method to evaluate the bond between the Composite and the metal inserts. The mechanical strength of the bonds was evaluated, both through tensile tests and four-point bending. A simple finite element model was used to discuss the joints behaviour. It was found that the joints fabricated using additive manufactured inserts were more resistant to peel stress than the milled inserts. In four-point bending tests the moment that the joint could withstand was increased by roughly 300% with the use of additive manufacturing and 400% with the use of additive manufacturing and small teeth. However, in tensile tests it was found that the teeth design reduced the maximum load capacity of the joints by roughly 30% due to porosity. Further, it was found that the additive manufactured samples did not add to the capability of withstanding shear stress. The information gained with the dual-energy computed tomography method was highly valuable as the behaviour of the joints would have been difficult to explain without the porosity information.
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Dual-energy computed tomography investigation of additive manufacturing aluminium–Carbon-Fibre Composite joints
Elsevier, 2019Co-Authors: Anton Jansson, Lars PejrydAbstract:In this work, aluminium–Carbon-Fibre reinforced plastic joints have been studied. Three types of samples were designed as double lap joints where the aluminium inserts were fabricated using both classical methods (milling) and additive manufacturing. Two versions of the joint were fabricated using additive manufacturing, one flat, and the other with small teeth designed to hook into the Carbon-Fibre plies. The joints were characterised using a non-linear, dual-energy computed tomography method to evaluate the bond between the Composite and the metal inserts. The mechanical strength of the bonds was evaluated, both through tensile tests and four-point bending. A simple finite element model was used to discuss the joints behaviour. It was found that the joints fabricated using additive manufactured inserts were more resistant to peel stress than the milled inserts. In four-point bending tests the moment that the joint could withstand was increased by roughly 300% with the use of additive manufacturing and 400% with the use of additive manufacturing and small teeth. However, in tensile tests it was found that the teeth design reduced the maximum load capacity of the joints by roughly 30% due to porosity. Further, it was found that the additive manufactured samples did not add to the capability of withstanding shear stress. The information gained with the dual-energy computed tomography method was highly valuable as the behaviour of the joints would have been difficult to explain without the porosity information. Keywords: Mechanical engineering, Materials scienc
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characterisation of additive manufacturing metal Carbon Fibre Composite bond by dual energy computed tomography
EUSPEN Conference Proceedings Special Interest Group: Dimensional Accuracy and Surface Finish in Additive Manufacturing Katholieke Universiteit Leuven, 2017Co-Authors: Anton Jansson, Lars PejrydAbstract:Joining of dissimilar materials is a topic of high interest for the industry. The ability to seamlessly join materials with significant differences in properties would advance the development of ef ...