Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Investigation of the influence of a highly permeable layer on the transverse permeability determination of RTM fibrous reinforcements
Submission Author:
Gustavo Pereira , RS
Co-Authors:
Gustavo Pereira, Douglas Cardoso, Cristiano Oliveira, jeferson Avila Souza
Presenter: jeferson Avila Souza
doi://10.26678/ABCM.COBEM2023.COB2023-1323
Abstract
The transverse permeability of reinforcement materials is one of the variables that determines the rate of resin flow in the composite part injection process. A low transverse permeability can lead to incomplete resin impregnation and void formation in the composite part, resulting in reduced mechanical properties and potentially compromising the structural integrity of the part. The constant flow method (saturated) is a technique used to measure transverse permeability in the resin transfer molding (RTM) process. This method involves placing a thin, flat sample of the reinforcement material between two plates, and then applying a constant resin flow to one side of the sample. As the resin flows through the sample, it is collected on the other side and the flow pressure drop is measured. The transverse permeability of the reinforcement material can then be calculated based on the flow rate, pressure drop, resin viscosity and thickness of the sample using the Darcy's Law. Thus, when defining permeability in the transverse direction, it is important to ensure a rectilinear (1D) resin flow inside the mold cavity. Some studies have shown that the incorrect distribution of holes in the perforated plate may not produce the 1D flow behavior, resulting in large errors in transverse permeability calculations. The objective of present work is to numerically evaluate the possibility of eliminating these errors by including a highly permeable layer before the fibrous reinforcement region. For this purpose, a numerical study is presented on which fluid flow through the reinforcement fiber region and a highly permeable layer is modeled as a porous medium. A two fluid flow (air + resin) is modeled with the Volume of Fluid (VoF) method. GMSH software is used to create and discretize the geometry and OpenFOAM software is used to solve the flow problem, determining pressure drop and flow rate inside the mold. Results show that the highly permeable layer tends to decrease the error in determining the transverse permeability of the fibrous reinforcement in up to 20%.
Keywords
transverse permeability, polymer composites, Resin Transfer Molding, numerical solution
