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El presente artículo analiza las propiedades tensiles de un material compuesto polimérico reforzado con fibras de carbono empleado en la fabricación del monoplaza para competición Fórmula SAE. Para ello se manufacturaron compuestos a partir de preimpregnados con diferentes orientaciones de fibra mediante un proceso de curado al vacío. Se evaluó el efecto de la orientación de las fibras sobre la resistencia y la rigidez de los compuestos formulados. Se instrumentaron las probetas de tracción con extensómetros biaxiales para obtener un registro real de la deformación y posterior determinación del módulo de Young. Los resultados experimentales fueron comparados con los resultados analíticos obtenidos a partir de la Teoría Clásica de Laminados mediante software especializado. Se desarrolló también un análisis microscópico de la región fracturada de las probetas para evaluar el efecto del proceso de manufactura. El conjunto de información generada a partir de los resultados experimentales y analíticos proporciona un entendimiento de la anisotropía de los materiales compuestos Epoxi-Carbono que permitirá tomar decisiones de diseño en futuros desarrollos dentro del proyecto Fórmula SAE.

Pre-preg material has been widely-used in the industry of the aerospace, the wind power, which has many advantages on manufacture process, and can be chosen as an effective complementary insulation method for the Wet-winding and Vacuum Pressure Impregnation technology in the field of superconducting fusion magnets. ASIPP undertaken many engineering tasks on the superconducting coil and busbar design and manufacture for the large fusion device, the pre-preg material and the relevant curing technology were researched as a new method for the high voltage potential components in ITER Feeders, such as the busbars and current leads. Two types of Chinese industrial glass fiber pre-preg insulation composite material were studied and pre-qualified using vacuum bag and silicone rubber assistance technique in ASIPP. The mechanical properties including the ILSS and UTS at 77 K, and void content of this composites were measured and discussed in this paper in detail.

Flexural properties of carbon fibre reinforced plastics (CFRPs) with multi-layer interfacial reinforcement of hierarchically structured aramid pulp (AP) fibres were measured at −40 and −100 °C under three-point bending (3 PB) together with unreinforced CFRPs. After curing, the ‘interleaf’ thicknesses were 3.3, 5.6 and 12.2 μm for three different AP areal densities of 0.8, 1.6 and 3.2 g/m2, respectively. 3 PB tests of control and AP reinforced CFRPs were also performed at 20 °C to compare the AP strengthening effects and their variations from ambient temperature to −100 °C. The flexural strength increased up to 30.6% at −100 °C for specimens with 1.6 g/m2 AP in comparison to 24.5% enhancement at room temperature. This finding proves that a proper composite design, i.e. adding tough and flexible short fibres into the brittle-fibre and brittle-matrix system, can indeed enhance the structural performance of CFRPs. The small-scale in-house ‘pre-preg’ fabrication adopted in this study shows that the ultra-thin layers of AP fibres can be potentially incorporated into a large-scale pre-preg production so that the extra step of inserting the interleaving layers can be removed from the composite forming process. In other words, end users can use the AP toughened pre-pregs just like any carbon fibre pre-pregs currently in use without the trouble of interleaving.

In situ consolidation of pre-impregnated thermoplastic composite requires as much as possible intimate contact as well as an appropriate molecular diffusion across the interface where the intimate contact takes place. The last depends on the temperature that influences the molecular mobility. Thus, in order to evaluate the consolidation first we must describe accurately the composite surfaces and then, when placed in contact for manufacturing the laminate, a high-resolution simulation of the resulting thermal model must be accomplished to have access to the thermal history at the rough contact surface. In this paper based on a fractal description of the composite surface, the evolution of the intimate contact is performed by solving the flow equations during the compression. High-resolution thermal simulations based on the use of the proper generalized decomposition – PGD – are carried out on the geometrically evolving composite surface.

A novel pre-preg coating method was used to improve the interlaminar fracture toughness in carbon fibre epoxy composite laminates, using reactive liquid rubber. The Epoxy Terminated Butadiene Nitrile (ETBN) liquid rubber incorporated between pre-pregs using automatic draw bar coating technique. Experimental test results reveal that by adding ETBN in small quantities in the range of 15.55–22.66 g/m2, inter laminar critical energy release rates (GIC and GIIC) can be improved up to 140% in mode-I loadings and 32% in mode-II loadings respectively. It was confirmed that the effect of ETBN rubber concentration in carbon epoxy pre-preg system on interlaminar fracture toughness under mode-I and mode-II loadings, was discussed by on the bases of fractographic observations and mechanism considerations using SEM.

This paper introduces an experimental and numerical investigation into hollow cylindrical thin-walled glass fibre reinforced epoxy matrix composite shafts produced by using both pre-preg wrapping and filament winding methods. The filament wound samples were manufactured with four different helix angles ([±30]FW, [±45]FW, [±60]FW, and [±75]FW ), whereas [0, 90]PP pre-pregs was utilised for producing the wrapped kind of samples. In order to assess the quasi-static failure responses, the samples were subjected to increasing amount of torsional load at a fixed angular rotation speed. The experimental findings of [±30]FW, [±45]FW, and [±60]FW samples were found to be very compatible with those obtained via Finite Element Analysis (FEA). Contrarily, the numerical model were not able to describe accurately the load—displacement behaviour of [±75]FW and [0, 90]PP with the exception of the initial loading phase. [±45]FW was found as the most favourable option for designers in terms of torsional stiffness. Whereas, those characterised by [±30]FW, and [±60]FW exhibited very close torsional resistances in a difference range of only 5%. [0, 90]PP exhibited the lowest average torsional failure resistant and stiffness but the highest average rotation angle before rupture.

A study concerning the application of fiber laser to perforate thermoplastic pre-pregs is presented. An IPG fiber laser was used to drill arrays of holes in PEKK carbon-fiber composite pre-preg material. Perforated holes were of the order of 100μm. The effects of laser perforation process parameters including the number of pulses on the geometry of the resultant holes and the thermal damage to the matrix and fibres have been investigated. Dimensional analysis and experimental results have been used to construct the laser perforation process model. Keywords: Laser perforation; Fibre laser; Process modelling; Polymer matrix composites.

Pre-preg and non-crimp-fabric composite single lap bonded joints were manufactured and investigated to characterise the bond quality and static failure behaviour. A two-part epoxy adhesive was employed to bond composite laminates. The composite panels, which were treated with low pressure oxygen plasma, were bonded in a hot drape former and then cut to manufacture single lap bonded joints. The joints were examined using X-ray microtomography to evaluate the bond quality achieved in the hot drape former. Quasi-static tensile tests were conducted on the pre-preg and non-crimp-fabric composite single lap bonded joints. The fracture surfaces were examined using optical and scanning electron microscopy. The static failure behaviour and failure patterns observed in the two joint types were compared and discussed.

The content of the scientific work is to evaluate the properties of matrix pre-preg systems of composite materials suitable for the production of high performance composite parts, for example for automotive or aerospace industry. The research work introduces composite materials, types, properties and fields of use of matrices and fibres. The main part deals with the description of the pre-preg production, the description of the state of the material conversion with a focus on the B-state of the resin, including the technologies for the production of composite materials from pre-preg systems. The practical part is focused on the testing of matrices intended for the manufacture of pre-preg systems of composite materials, it compares different types of epoxy matrix and glass fiber in several layers. The aim of the work is to evaluate the tested composite systems suitable for pre-preg applications, to compare the properties and parameters of the given application with the focus on the recommended production methods. The result of the work can then be used as the most suitable production application according to the customer's requirements for the product.

This paper presents a novel approach to toughen the otherwise brittle unsaturated polyester resin (USP) in the polymer matrix biofiber composites. In contrast to the conventional method of incorporating the toughening agent in the matrix resin, the method used in the present investigation consisted in treating the biofiber (OPF) with the toughening resin before impregnating with USP resin. Accordingly biofiber was first impregnated with toughening resin, acrylonitrile-butadienne-styrene (ABS) to produce a pre-preg. The pre-preg was then impregnated with USP resin containing free radical initiator. The ABS content in the biofiber pre-preg was varied from 5 to 25%. Unsaturated polyester was reinforced with the pre-preg and cured in presence of MEKP to produce “hybrid composite”. The physical and mechanical properties of the composites were determined.

Shape memory alloys (SMA) exhibit functional properties associated with the shape memory effect, responsible of the SMA shape recovery after a cycle of deforming-heating and of a simultaneous generation of mechanical work. Composite systems incorporating SMA wires have the ability to actively change shape and other structural characteristics. The functional properties of such adaptive composites are related to the martensitic transformation in the SMA elements and to the constraining behaviour that the composite matrix has on the SMA wires. In this work the behaviour of a shape memory alloy hybrid composite (SMAHC) is numerically and experimentally investigated. A plate was fabricated using prestrained SMA wires embedded in an epoxy resin pre preg glass fibres composite system. Upon calorimetric and mechanical material characterization, a finite element model was used in order to predict the structural behaviour of the SMAHC. In the experimental tests, the plate was clamped at one side and actuated via electrical heating. Temperature and displacement data were collected and compared with the prediction of the finite element model. The results show that the model is able to capture the shape change in the actuation region, although a thorough description of the SMAHC behaviour requires further modelling work, including the simulation of the SMA loading history during composite manufacturing.

Polymeric matrix composites are the standard materials used in the construction of Formula 1 racing cars. The transition to these from metallic types for primary load-bearing structures began in 1980 and progressed rapidly thereafter. The original reason for the change was a perceived lack of stiffness in the main semi-monocoque chassis relative to that required for the increased aerodynamic loading being generated from that time onwards; vehicle performance, meanwhile, is also strongly affected by mass. Composites, therefore, provided an improvement in stiffness for no weight penalty. Stiffness design, however, was only one consideration as, in an activity where there is substantial inertial loading – and high probability of collision with barriers or other cars – strength is a parallel consideration. The range of design criteria for composites within the assembly is broader, however, also covering impact energy absorption, damage resistance, fatigue durability, and environmental tolerance. Manufacturing methods are largely confined to the use of carbon/epoxy prepregs, composite tooling, and autoclave curing. In this fast-moving industry, evolution of design thinking is rapid and component complexity is extreme but unit numbers of parts are low; intricacy in designs is, therefore, tolerable.