The permeability of fibrous preforms used as reinforcements for fiber‐reinforced polymeric composites is a decisive parameter for simulation‐based predictions of common defects that occur during the filling process. This study focuses on the transverse permeability which becomes important for high thickness parts. An instrument that detects the transverse flow front by ultrasound and determines the transverse permeability has been developed. In contrast to other approaches, the developed permeameter uses a nondeflecting (metallic) tool while the selected sensing method is nonintrusive to the material. Novel electromechanical features allow a wide range of measurable preforms. The remaining limitations of the system have been identified and the model that correlates raw ultrasound measurements with flow front has been verified by visual observations. The transverse permeabilities of 18 different preforms have been determined in an experimental scheme designed to isolate the influence of preform thickness. POLYM. COMPOS., 39:360–367, 2018. © 2016 Society of Plastics Engineers

This paper is dealing with the influence of processing parameters for manufacturing of steel-carbon-fiber-reinforced-plastic (CFRP) hybrid plates by using the one-shot-hybrid resin-transfer-moulding (OSH-RTM) process. A design of experiments study was carried out. The quality of the manufactured parts was quantified by the bending modulus, the apparent interlaminar shear strength (ILSS), the maximum deflection and the density of the CFRP. The following changeable processing parameters were chosen: mould temperature, resin temperature, change in mass flow and maximum injection pressure. It is shown that the mould temperature and the change in mass flow show significant impact on the flexural modulus, density and maximum deflection of the plate while there is no significant impact on the apparent ILSS. Furthermore, the interaction between the mould temperature and resin temperature is having an influence on the flexural modulus and density.

The production of fibre metal laminates (FMLs) is a time consuming and expensive procedure. This paper shows the application of the vacuum assisted resin transfer moulding ((VA)RTM) technique using an injection unit and a rigid mould for the production of FMLs. This processing technique, in combination with a corona discharge activation of the aluminium surface, can lead to enormous reductions to the cycle time. To prove the quality of the produced FML, impact tests were carried out. The influence of the impact energy on the specimen is observed using a deformation scan and ultrasound C-Scan. Furthermore, the peak forces and permanent deflections of the tested specimen were analysed.

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HybridRTM terms a publicly funded project, which aims at the development of a processing technique for manufacturing of light weight structural components from hybrid materials. In particular, components involving metal as well as fibre-reinforced polymer composite materials are manufactured in a single processing step by means of the resin transfer moulding (RTM) technique. Project activities include material development and characterization, modelling of thermally induced residual stresses, process simulation, mould development as well as model-based process control in order to ensure consistently high component quality. This paper outlines the fundamental idea of the project and summarizes the most important results gained during the first two years of project activities.

This work describes a model-based methodology to improve the bonding quality between the metal and composite constituents of one-shot-hybrid resin transfer moulding (OSH-RTM) parts. In order to reduce void induced defects in the interface an ideal flow front velocity needs to be achieved. This ideal flow front velocity is characterised by capillary rise experiments at the used carbon fibre textile. The flow front velocity during mould filling is controlled by the use of pressure sensors and Darcy's law. Therefore, viscosity characterisation of the resin system and permeability measurements of the preform were carried out. The interface of the produced OSH-RTM roof bar for a car is tested on a component test rig imitating the load of a side impact at a car. A t-test was carried out to prove that the flowspeed-controlled injection strategy is advantageous compared to a constant mass flow injection by means of a higher maximum load transferable by the interface of the hybrid part.

This work shows a new way of single lap shear specimen production for hybrid metal-composite materials, which can be used to characterize process-induced interface property variations. Due to this special procedure, the specimen manufacturing can be done production-related and with a homogenization of the thermal stresses occurring in the joint area of the hybrid at each specimen. The exemption process of the specimen is kept in a minimum invasive way, not affecting the interface in the tested zone. The influence of the metal surface structure specifically created by micro form milling as well as the influence of the curing temperature on the maximum shear strength of the interface, were investigated. Finally, the driving failure mechanisms were identified and described.

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