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Different Techniques for Designing and Fabrication of Advanced Composite Materials
Published in Subhash Singh, Dinesh Kumar, Fabrication and Machining of Advanced Materials and Composites, 2023
Subhash Singh, Rama Kanti, Vikas Kumar
The RTM process, employs a closed mould in which the resin is transferred to a pre-existing reinforcement (woven/strand mat) placed over a lower half of a mould. This mould surface is coated with a release gel for a composite to be easily removed and then the mould is closed using a clamp. The mechanism of clamping employed is either press or a perimeter clamping. The uniform pumping of the resin occurs via mould ports seeking the support of a catalyst as well as vacuum, resulting in air displacements via vents. Once cured, the composite is removed by opening the mould. The resin as well as the catalyst are store in diverse containers (Fig. 3.4) in which resin is stored in a larger one [16]. Each container has its own outlet that pumps the respective contents into a mixing chamber where the resin as well as the catalyst are mixed thoroughly. Resin is then injected via an injector, into a mould cavity comprising two halves (upper/lower) with an integrated heating system. The unwanted gases escape via the vents at the time of clamping.
Fabrication of Composites
Published in Shishir Sinha, G. L. Devnani, Natural Fiber Composites, 2022
Ishan Srivastava, G. L. Devnani, Shishir Sinha
Resin transfer molding (RTM), is a closed-molding fabrication process. It is high standard composite preparation method that works on low temperature and low pressure. The pressure usually varies from 3.5–7 bar. The dimensions of the molded composites are accurate to a large extent and provide a good surface finish. RTM is capable of dealing with an intermediate amount of volume and produces a two-ended surface finished composite. It offers a wide variety of composites that includes two-dimensional and three-dimensional materials.
Conventional Processing of Polymer Matrix Composites
Published in Sanjay Mavinkere Rangappa, Jyotishkumar Parameswaranpillai, Suchart Siengchin, Lothar Kroll, Lightweight Polymer Composite Structures, 2020
M.K. Singh, N. Verma, S. Zafar
RTM is used to fabricate the composites which are of high-end use. The RTM technique produces high-strength composites that are used for aerospace applications. With the advancement in technology of RTM, it is used to produce lightweight products with excellent mechanical properties.
Investigation of the bending behaviour of multi-ply dry carbon fibre non-crimped fabrics
Published in The Journal of The Textile Institute, 2018
Timo Grieser, David Becker, Peter Mitschang
Resin Transfer Moulding (RTM) is an established liquid composite moulding (LCM) process, which potentially allows realization of mass production (Neitzel, Mitschang, & Breuer, 2014). The RTM process chain can be split into two main phases: preforming (fibre structure preparation) and injection (impregnation of the fibre structure with a matrix system). In this context, compared to the injection phase, the efficiency and robustness of the preforming phase is more deficient and can therefore be seen as a key element for further improvement of RTM, respectively, LCM (Arnold, Rieber, & Mitschang, 2012).
The effect of molding process on thermomechanical properties of feather nonwoven reinforced polyester composites
Published in The Journal of The Textile Institute, 2022
Ouahiba Mrajji, Mohamed El Wazna, Abdeslam El Bouari, Omar Cherkaoui
Several molding techniques can be applied for feather nonwoven reinforced composite fabrication. Some are based on the polymerization of the polymer in the mold. One of these methods is ‘resin transfer molding’ (RTM). In this process, the fiber reinforcement is put in a mold cavity and the resin is introduced by injection. In comparison with the other methods, RTM is a simple and economical method. The only problem with this method is the low fiber volume fraction, which could also be overcome by using denser fibers. In RTM, the catalyzed resin is injected under a pressure of 1000 bar into the mold through a properly positioned injection port. The injection is stopped when the mold is completely filled with the resin, and the sample is subsequently cured. After the polymerization, the sample is removed from the mold (Van den Broek d’Obrenan, 2011). The vacuum molding process is similar to contact molding, except that it is carried out under a vacuum of 500 bars. The first step in vacuum molding is to prepare the mold to receive the different types of reinforcements; a release agent can be applied to facilitate the demolding of the sample. The reinforcement in the form of mat or tissue is impregnated with resin, usually manually, until the desired thickness. The air is emptied from the mold and once the polymerization is complete, the sample is demolded (Merad, 2010). Infusion molding was developed to reduce the costs and constraints associated with the use of RTM. It doesn't require the use of a counter-mold or oven, which reduces investment costs and sample size limitations. In infusion molding, reinforcements are installed in the mold and then the vacuum system is applied. The air is removed from the mold and the catalyzed resin is injected inside the mold under a low pressure of 500 bar (Blais et al., 2016).
Parallel optimization of design and manufacturing—Carbon fiber battery pack for electric vehicles
Published in Mechanics of Advanced Materials and Structures, 2022
Qi-hua Ma, Fan Dong, Xiao-yu Qin, Xue-hui Gan, Ming Cai
The excellent performance and designable features of carbon fiber composites should have achieved rapid development in various transportation fields, but the immaturity of the process technology has limited its large-scale application. The molding method, hand layup, vacuum infusion, split forming, and vacuum bagging method [19–21]. Among them, the resin transfer molding (RTM) molding process is used for the mass production of composite parts with high precision, high efficiency, and low cost [22]. Shi and Dong [23] discussed the time analysis step, heat of reaction, thermal conductivity of the fibers and resin, and initial temperature of the fibers for the RTM process. Djebara et al. [24] developed an RTM global modeling approach based on previous work to simulate the resin flow during RTM fabrication and predict the effective heat transfer of the composite. Huang et al. [25] revealed the whole process of resin flow and infiltration during the molding process by numerical simulation to visualize the process. Shimada et al. [26] focused on the numerical simulation of defect prediction during RTM molding, using boundary element and line dynamics methods to simulate small molding defects by adding nodes at desired locations in the time evolution process. The level of RTM is increasingly advanced by researchers, but they focus only on the parameters of the curing process and ignore the presence of molding defects. Combined with the heavy difficulties of actual carbon fiber processed products, cutting and layup are the most important processes in RTM molding. Most of the current scheme designs realize the preprocessing performance prediction by finite element technology, which ignores a difficult point, namely, the fiber bundle cluttering at the fiber cutting. To solve the fiber uncontrollability problem, preprocessing simulation of the product before manufacturing is performed by Fiber Sim software in this paper to achieve the parallel structural design-manufacturing optimization [27, 28].