Experimental investigation of high fiber tow count fabric unsaturation during RTM

Effect of deformation on knitted glass preform in‐plane permeability

“…At low velocities, the capillary forces are predominant, and the flow takes place preferentially inside the yarn, whereas at high velocities, the flow takes place preferentially in the macropores, leading to the formation of microvoids inside the yarns. The existence of an optimal flow front velocity or, more generally, an optimal capillary number has been demonstrated experimentally [44,45] and is used to minimize the micro-and macrovoids formation [46,47]. Unfortunately, the present setup is not suitable to regulate flow-rate accurately because of the time response of the solenoid valve, whereas constant pressure experiments can be performed in conditions meeting identification method requirements.…”

Estudo do processamento de materiais compósitos com inserts impermeáveis embebidos via RTM

“…Gourichon et al, 2005 De acordo com Garay (2010), o RTM light utiliza pressão positiva e pressão a vácuo simultaneamente para a injeção, distinguindo do processo convencional de RTM, ou seja, nesse processo há um equipamento responsável por injetar resina no molde com pressão positiva e outro que vai gerar pressão negativa responsável pela retirada de ar e vedação do molde. Ambas as pressões possuem baixos valores, próximo a 0,7 bar para a pressão positiva de injeção e 0,6 bar para a pressão a vácuo (GOURICHON et al, 2006 Algumas vantagens como baixo custo de processo e projeto do molde, fazem o processo de VARTM ser atrativo quando comparado com processos como laminação manual e autoclave. Boas propriedades mecânicas, baixo teor de vazios, elevado teor de fibras e por utilizar molde fechado, não há emissão de estireno para o meio, reduzindo danos ao ambiente eà saúde (GARAY, 2010).…”

Application of calcium carbonate in resin transfer molding process: An experimental investigation

“…In many cases, the resin is injected together with solid particles, such as calcium carbonate, in an attempt to improve the mechanical properties of the composite and optimize the process . Several authors have carried out experimental investigation in resin transfer molding .…”

“…Lebrun et al report that the use of heated resin transfer molding moulds filled with a resin at ambient temperature has been proved to be effective in lowering the overall cycle time by reducing the filling and cure cycle times . Gourichon et al in their research related to resin transfer molding process noted that a impregnation of fiber clusters may lead to local incomplete saturation of fabrics, mechanical softening, early failure, or part rejection because of high voids content . A new experimental method has been proposed to measure the air volume entrapped within the wetted part of the fabric at any given time and to quantify air entrapment kinetics.…”