Numerical Determination of Permeability Tensor Components for 3D-braided Composites Using RVC Approach

摘要

Today, one of the most promising trends in the design and manufacturing of composite structures is the use of 3D-reinforced thermoplastic composites. The present paper is concerned with the problem of resin transfer molding (RTM) process modeling, which is an important stage of 3D thermoplastic composites design. It is known that during the impregnation of woven preform local starved spots may occur, the textile pattern may distort and as a result the final structure will differ in mechanical properties form the initial design. The proper selection of RTM process parameters, such as injection holes placement, pressure profile and flow rate is a challenge for designers and process engineers. Nowadays, specialized software is developed for the solution of that problem, but the RTM process modeling in these environments is associated with considerable difficulties, caused by the need to set the permeability tensor, which components should be determined experimentally for each fiber material and for each weaving type. However, the permeability parameters can be determined in virtual experiments using the representative volume cell (RVC) approach by simulating a coupled-field problem of a viscous incompressible fluid flow through a porous medium. The paper demonstrates such an approach for permeability tensor components determination for the chosen 3D textile pattern using LS-DYNA with ALE computational method. Resin flow interaction with the fibers is modeled using FSI approach, while the flow through the fiber material is described by Darcy's law. As a result, resin pressure drop curves along three RVC directions were determined, on the basis of which the permeability tensor components were obtained.