The present study deals with the numerical modelling of hybridlaminated composites, which can be proved especially useful in theengineering and maintenance of advanced aerospace primary structures. Thelamina is comprised of continuous carbon fibers, thermosetting epoxypolymer matrix, as well as carbon nanostructures, such as graphene orcarbon nanotubes, inclusions. Halpin-Tsai equations combined with resultsobtained from nanomechanical analysis are employed in order to evaluatethe elastic properties of the carbon nanostructure/polymer matrix. Then, theobtained elastic properties of the hybrid matrix are used to calculate theorthotropic macro-mechanical properties of the unidirectional compositelamina. A hybrid composite plate is modelled as a 2D structure via theutilization of 4-node, quadrilateral, stress/displacement shell finite elementswith reduced integration formulation. The convergence and analysisaccuracy are tested. The mechanical performance of the hybrid compositesis investigated by considering specific configurations and applyingappropriate loading and boundary conditions. The results are compared withthe corresponding ones found in the open literature, where it is possible.
Stricter environmental policies, increased energy prices and depletion of resources are forcing industries to look for bio-based and low carbon footprint products. For industries, flax is interesting resource since it is light, strong, environmental friendly and renewable. From flax plant to fiber products involves biochemical and mechanical processes. Moreover, production and processing costs have to compete with other products, like petroleum based materials. This research focusses on sustainable process improvement from flax plant to fiber production. Flax retting is a biological process at which mainly pectin is removed. Without retting, the desired fibre remains attached to the wooden core of the flax stem. As a result, the flax fibres cannot be gained, or have a lows quality. After retting, the fibers are released from the wooden core. Furthermore, machines have been introduced in the flax production process, but the best quality fibers are still produced manually. Due to the high labor intensity the process is too expensive and the process needs to be economical optimized. Since the retting process determines all other downstream processes, retting is the first step to focus on. Lab-scale experiments were performed to investigate the retting process. Factors that were researched were low cost processing conditions like, temperature, pH, dew retting and water retting. The retting rate was low, around three weeks for complete retting. The best retting conditions were at 20°C with water and any addition of chemicals. The process could be shortened to two weeks by recycling the water phase. In a scale-up experiment, a rotating drum was used at the optimal conditions from the lab-experiment (20°C and water). First the flax did not mix with the water content in the rotating drum. The flax was too rigid and did not tumble. Therefore, bundles of flax plants were used. The inner core of the bundle seemed to be protected and the retting rate was less compared to the flax on the surface of the flax bundle. This implies that mechanical impact increased retting in the rotating drum, however heterogeneous retting should be avoided. To overcome the heterogeneous retting problem, a water column was used to improve heterogeneous retting. Retting was performed in a water column and mixing was accomplished by bubbling air. As a result of the mixing, the flax bundle was retted homogenously. And after drying, it was possible to separate the fibers from the wooden flax core. Retting with a bubble column can overcome this problem and seems to be a usable retting process step. Water samples of the lab-scale experiments, the rotating drum and the bubble column showed a chemical oxygen demand (COD) content up to 4 g/L. Overall, 1 kg Flax resulted in 40 g COD. This indicates the possibility to produce biogas that can be used for generating heat and electricity, to make the process sustainable. Around 50% of the weight consists of wooden shives. The shives can be used for pyrolysis and it was possible to produce around 30% coal and 20% oil. These compounds can be used as building blocks, but also to generate heat and electricity. Heat and electricity can be used for the flax processing. Shives were only dried for 1 day at 105°C and slow pyrolysis was used. This indicates that a higher yield can be expected at fast pyrolysis. Overall, the reported implicates that quality fiber production from flax plant can be a feasible, sustainable and a renewable production process. Feasibility of the process can be obtained by, (1) retting at low-cost process conditions of 20°C and using water without any addition of chemicals, (2) with increased flax retting rate by recycling water, (3) with increased flax retting rate by introducing mixing forces, and the ability to lower the energy consumption of the overall process, (4) producing biogas from the COD with anaerobic digestion and (5) producing pyrolysis oil and pyrolysis c
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In the high-tech mechatronics world, aluminum and steel are well known materials, while carbon fiber is often neglected. In the RAAK project 'Composites in Mechatronics', the use of carbon fiber composites in mechatronics is investigated.
Paper sludge contains papermaking mineral additives and fibers, which could be reused or recycled, thus enhancing the circularity. One of the promising technologies is the fast pyrolysis of paper sludge, which is capable of recovering > 99 wt.% of the fine minerals in the paper sludge and also affording a bio-liquid. The fine minerals (e.g., ‘circular’ CaCO3) can be reused as filler in consumer products thereby reducing the required primary resources. However, the bio-liquid has a lower quality compared to fossil fuels, and only a limited application, e.g., for heat generation, has been applied. This could be significantly improved by catalytic upgrading of the fast pyrolysis vapor, known as an ex-situ catalytic pyrolysis approach. We have recently found that a high-quality bio-oil (mainly ‘bio-based’ paraffins and low-molecular-weight aromatics, carbon yield of 21%, and HHV of 41.1 MJ kg-1) was produced (Chem. Eng. J., 420 (2021), 129714). Nevertheless, catalyst deactivation occurred after a few hours’ of reaction. As such, catalyst stability and regenerability are of research interest and also of high relevance for industrial implementation. This project aims to study the potential of the add-on catalytic upgrading step to the industrial fast pyrolysis of paper sludge process. One important performance metric for sustainable catalysis in the industry is the level of catalyst consumption (kgcat tprod-1) for catalytic pyrolysis of paper sludge. Another important research topic is to establish the correlation between yield and selectivity of the bio-chemicals and the catalyst characteristics. For this, different types of catalysts (e.g., FCC-type E-Cat) will be tested and several reaction-regeneration cycles will be performed. These studies will determine under which conditions catalytic fast pyrolysis of paper sludge is technically and economically viable.
Lichtgewicht voertuigen voor stadsdistributie bestaan voor een belangrijk deel uit vezelversterkte kunststoffen zoals carbon fiber reinforced polymers. De productie hiervan is tijdrovend en recycling is maar beperkt mogelijk. Het realiseren van zero-emissie stadsvervoer in 2025 wordt met de bestaande technologie duur en niet circulair. ModuBase beoogt een nieuw recyclebaar polymeer in combinatie met een Added Manufacturing platform (3D Printen) te ontwikkelen. Hiermee wordt het mogelijk om volledig recyclebare kunststoffen 3D te printen dichtbij de montage van de voertuigen. Supply chains worden zo korter, gebruikers en ontwerpers krijgen meer ontwerpvrijheid en de grondstof is (oneindig) recyclebaar. Dit consortium maakt gebruik van een nieuw ontwikkeld thermoplastisch polymeer en gaat dit voor het eerst toepassen in 3D printing. Hiervoor is een consortium voorzien met de materiaalexpertise (DSM), 3D Printexpertise (CEAD) en werktuigbouwkundige ontwikkelexpertise (Fontys). De materialen worden uitvoerig bestudeerd voor automotive toepassingen, ontwerpregels worden opgesteld en eerste werkstukken worden geprint. Materiaaleigenschappen en recyclebaarheid na het printen worden in testopstellingen ge-evalueerd. Resultaat is een proof of concept van een vezelversterkt 3D print platform. Het betrokken industriële (automotive) cluster van Brainport wordt geïnteresseerd om met de nieuw ontwikkelde 3D printkennis prototypes voor Light Electric Vehicles onderdelen te gaan ontwikkelen en onderzoeken.
