Papers by Keyword: CFRP

Abstract: If the attention is not paid to the crack in a structure, then it could suddenly propagate at a rapid rate and rip apart the structures. A small crack needs urgent attention and repair since replacing the parts with a small crack is not economically feasible at all the time. Repairs were used to be carried out through rivets, welding and nut-bolts, but recently composite materials are showing promising results in this field. Since composite material are anisotropic in nature their application needs careful study about the loading pattern on the repaired structure. In this study, Carbon Fiber Reinforced Polymer (CFRP) was used as a composite material to repair Aluminium alloy specimens. These specimen were subjected to a three-point bending load to investigate the effectiveness of CFRP. By using innovative ply drop technique and design of experiment a configuration was selected to sustain three-point bending load. To suppress the CFRP’s peeling off tendency, attention was given to the interfacial shear stress rather than to the fracture toughness parameter.

Abstract: At the time of unprecedented development of digital technologies, business owners across various industries need to stay up-to-date in terms of using cutting-edge technologies such as Industry 4.0 to ensure competitive performance. There are still many areas where their positive implications of digital technologies have not been applied. For example, the end-of-life (EoL) waste from the automotive, aerospace, and wind energy industries is still accumulating in landfills. At present, an increasing number of vehicles, airplanes, and wind turbine blades are made of Carbon Fiber Reinforced Polymer Composites (CFRPs) leading to an urgent demand for implementing sustainable waste disposal strategies. Thus, recycling CFRPs is a key research area that provides a potential for improvement, particularly, in terms of digitalization. This study addresses the issues prevalent in this sphere and proposes Industry 4.0 related technologies to be integrated into the CFRP recycling supply chain stages, including waste collection, dismantling, transportation, recycling, and re-manufacturing. For this purpose, key technologies were selected from the literature review, smart recycling trends were defined and relevant analysis was carried out to map technologies onto the CFRP recycling supply chain.

Abstract: The purpose of this study is to investigate the effect of bending-twisting coupling deformation on the bending strength of CFRP in which laminate configuration has symmetricity and angled fiber orientation. In this study, a novel type of test fixture for pure bending test that permit the coupled bending-twisting deformation is newly developed. Test results showed that the pure bending strength of the angle-ply laminates was decreased when bending-twisting coupled deformation was permitted. The normalized bending strength when the bending-twisting coupled deformation is permitted was decreased with increase of coupled component of angle-ply laminate. Observations of fracture morphology of specimen also showed that the specimen was firstly failure at the 0° layer on the compression side, no matter if the coupled deformation was permitted or constrained. However, when the coupled deformation was permitted, the failure was occurred at lower applied bending stress compared with when coupled deformation was constrained. Moreover, when the coupled deformation was permitted, the failure of 0° layer was occurred at the diagonal portion of specimen. These results suggested that the existing of in-plane shear stress at 0° layer affects the fracture morphology of specimen.

Abstract: Weight reduction is often a key factor in modern mechanical design, therefore materials such as carbon fibre reinforced plastics (CFRP) are increasingly used and integrated within multi-material structures using adhesive technologies, which require high effort and are difficult to disassemble. The capability of a blind rivet nut (BRN) to join different materials without these disadvantages has created a growing industrial interest in the fastener. However, installing a BRN in CFRP laminate induces a significant stress concentration in the plate, which potentially causes damage. Given that ‘damage free’ joints are demanded by the industry, the BRN is often not considered as a suitable joining technique. In the present research, an experimental campaign is performed to investigate the fatigue resistance of a BRN joint in CFRP. It is demonstrated that the resulting compressive stress after installing a BRN can enhance the fatigue resistance of the specimen. The results increase the potential of the BRN as a fastener for CFRP.

Abstract: The present work aims at studying the buckling behavior of lattice structures realized by additive manufacturing technology. To this purpose, carbon fiber reinforced thermoplastic filaments have been used to realize anisogrid structure at different geometric parameters by means of Fused Filament Fabrication technology. Eight configurations were realized varying the rib width and the rib thickness of the structures, and keeping constant the cell height value. Anisogrid structures were tested under compressive load in order to investigate the effect of geometric parameters on strength and specific strength exhibited by the structures. It has been shown that mechanical performances of lattice structures are highly affected by the geometric parameters of the anisogrids.

Abstract: Stochastic tow based discontinuous composites (STBDC) are fabricated from the compression molding of chips made from chopped and slit pre-impregnated uni-directional carbon fiber reinforced polymer (CFRP) tape. The discontinuous mesostructure gives the material system increased moldability versus continuous fiber composites allowing complex three-dimensional parts to be manufactured. However, the discontinuous mesostructure creates challenges for engineers designing parts as the effective properties are variable. Furthermore, the properties have been shown to be a function of the consolidation method of the chips. This study uses finite element analysis simulations of mesostructural representative volume elements to compare the elastic response and characteristics. The results are compared to the available literature regarding the elastic response STBDCs.

Abstract: Different commercial Finite Element Codes proved to be able to describe the mechanical behavior of masonry materials externally reinforced by means of Carbon Fiber Reinforced Polymers (CFRP); the behavior of fracturing materials, characterized by low tensile strength, with adhered strips can be reproduced relying on parameters based on fracture mechanics and the theories of adhesion.In this report the comparison is made of previous experimental test results with numerical analysis, carried out on masonry panels reinforced with CFRP strips and subjected to out of plane actions. The comparison is especially addressed to the evaluation of the post peak branch; in addition to the slopes of the diagram in the pre-critic phase, available kinematic ductility and energy shares both prior and after the peak load were considered in order to interpret the capability of the micro-mechanical model implemented in the FEM Code to account for the local phenomena influencing the interaction between masonry and FRP strengthening systems.

Abstract: Carbon Fiber Reinforced Polymer (CFRP) is an anisotropic material with outstanding tensile strength in the direction of axial but low compressive strength in the direction of radial, so the radial compressive failure and sliding failure are easy to occur in the practical application of compression and hanging wires. In this paper, the influence of different parameters on radial compressive failure and sliding failure is studied. The finite element method is used to simulate and analyze the CFRP and wedge clamp to find optimum condition parameters to make the CFRP neither sliding failure nor radial compressive failure. The parameters are as follows: interference between the CFRP and the inner wedge, friction coefficient between the CFRP and the inner wedge, angle of the wedge, inner wedge material elastic modulus. The results show that the most appropriate parameter is: the interference between 0.0236mm and 0.0252mm, the friction coefficient between 0.194 and 0.206, the wedge angle is greater than 1.75° and the elastic modulus of wedge material has little influence on the compressive failure and slippage failure of the CFRP.

Abstract: The paper presents the results of tests of carbon plastic samples consisting of carbon fabric Grafill TR30S-S (Italy) and epoxy resin binder EPR 320 modified by WC tungsten carbide nanopowders in the form of agglomerates. The positive effect of additives on the tensile strength and on the modulus of elasticity at transverse bending of the concentration of additives 1-3% is shown.

Abstract: This paper presents the experimental testing of eccentrically compressed reinforced concrete columns. There are experimental results of crack resistance of non-strengthened (control) and strengthened RC columns in the tension zone. The columns were strengthened by carbon fiber reinforced polymers (CFRP). As a result of experimental studies with the columns strengthened by CFRP, we obtain that the width of their crack decreased by an average of 33%. The eccentric compression load of the crack’s appearance increased from 40 kN to 60 kN for strengthened columns.