Resumo

PATINO ARCILA, Iván David. New approach for filling simulations of dual-scale preforms using BEM for manufacturing of composites materials. Rev.fac.ing.univ. Antioquia [online]. 2023, n.107, pp.66-79.  Epub 14-Jul-2023. ISSN 0120-6230.  https://doi.org/10.17533/udea.redin.20220783.

Some reinforcements used in the manufacturing of composites parts by Liquid Composite Molding (LCM) processes have a dual-scale nature, which supposes flow imbalances between the tows and channels at the mesoscopic scale, which in turn, cause uncontrolled defects (voids, dry points, among others) and could considerably affect the global flow behavior during the filling of cavities at a macroscopic scale. In the present work, a new approach to conducting filling simulations of dual-scale fibrous reinforcements at a mesoscopic scale is proposed. This consists of imposing a pressure gradient across the Representative Unitary Cell, and considering Stokes-Darcy coupling conditions between the porous and the free-fluid sub-domains to determine the filling of the former ones. Contrarily to the traditional approach, where a uniform pressure is assumed for the channels, and only the porous media fluid is modeled, the present approach allows considering the fluid motion at channels, flow-direction dependent capillary pressure, air compression and dissolution, and vacuum pressure, as well as capturing several phenomena of the evolution of intra-tow bubbles, namely, compression, mobilization at constant volume and migration from tows towards the channel. The velocity vectors and streamlines in the tows and channel subdomains, when these phenomena take place, are analyzed as well.

Palavras-chave : Fibrous reinforcements; liquid composite molding; multi-scale filling; boundary elements; polymers.

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