Resin Capacity of Technical Woven Fabrics: Pore Volume and Pore Shape Simulation
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ISSN 1229-9197 (print version) ISSN 1875-0052 (electronic version)
Resin Capacity of Technical Woven Fabrics: Pore Volume and Pore Shape Simulation Hamid Reza Sharafat1, Mehdi Kamali Dolatabadi1*, and Ali. A. A. Jeddi2 1
Departmentof Textile Engineering, Science and Research Branch, Islamic Azad University, Tehran 1477893855, Iran 2 Departmentof Textile Engineering, Amir Kabir University of Technology, Tehran 1591634311, Iran (Received May 14, 2019; Revised February 4, 2020; Accepted March 3, 2020) Abstract: Nowadays, technical woven fabrics are broadly utilized as reinforcement of composites. Resin capacity of woven fabric is one of the main challenges in laminate fabrication. Resin diffusion during fabrication of the composite is extremely depended on fabric micro-morphology. The geometry of weave unit cell and its pore are fundamental factors in evaluating resin capacity and resin diffusion within fabrics. The main attempt of this study was obtaining an approach to evaluate resin capacity of a woven fabric via simulating pore shape and pore volume. For this purpose, four basic unit cells for all kind of weaves were simulated with the two shapes of tow cross-section: lens and racetrack. Afterwards, 3D shape and volume of their pores were simulated using this approach. The proposed approach is established on the base of initial data of fabric such as tow setts, tow titers, planar density and thickness of a technical fabric. To assess the simulation, three types of woven fabrics namely, plain, twill and satin were impregnated by epoxy resin using vacuum infusion process. The volume fractions of the matrix and fibers of real composites were compared with simulated ones. It was demonstrated that the approach with racetrack assumption led to high degree of convergence with experimental results. The maximum relative error of pioneered method to evaluate volume of the pore in this condition exceeded up to 1.43 %. Suitable correlation between volume fractions of the pore and void was observed in experimental data. It is experimentally demonstrated that the void volume fraction of composite will be increased with decrease of pore volume due to difficulty of wetting. In this paper, it is illustrated that the resin capacity of a woven fabric is a function of vacuum level in vacuum infusion process. For instance, resin capacity of a certain plain fabric could be reduced up to 10 % under 60 kPa (0.6 bar) of vacuum in contrast with steady state of fabric at room atmosphere. Keywords: 3D shape of pore, Volume of pore, Resin infusion, Vacuum infusion process and, Woven fabric geometry
fabric’s structural properties [1,2]. Backer [3] demonstrated that the air permeability of a woven fabric corresponds with minimum pore area which can be obtained via slicing horizontally of the fabric unit cell. He defined four unit cells to evaluate this minimum pore area for all possible weaves of a fabric with circular tow cross-section. However, this method is time-consuming, and the results are depended on pitch of each slice. By increasin
