Vacuum infusion in porous preform with different mould configurations: Flow simulation and experimental validation

Abstract

The present work focuses on the formulation of transient incompressible resin flow during vacuum-assisted resin transfer moulding using level set front tracking method in a multi-block structured grid within a finite difference framework. Initially, the relation between compaction pressure and fibre volume fraction ([Formula: see text]) has been established by conducting compression tests using a universal tensile machine under dry and wet conditions. In-plane permeability has been characterised as a function of [Formula: see text] using three thicknesses of unidirectional carbon fabric (4, 8 and 12 plies). A pressure data acquisition system and a non-contact out-of-plane displacement measurement setup have been developed using a single lens camera to conduct the vacuum infusion experiments. The numerical model prediction of the instantaneous change in pressure, displacement, and fill time has been validated with the experiments for the three different thickness of unidirectional preform in a flat plate and a plate with a centrally located hole during vacuum infusion. The coupled transient flow model with the level set interface propagation in a multi-block framework shows a good agreement with vacuum infusion experiments. The proposed transient vacuum infusion flow model, compaction relation with [Formula: see text], permeability and experimental setup show the potential to capture realistic flow physics during vacuum infusion on different mould configurations.

Resin infusion in porous preform in the presence of HPM considering complex geometry and gravity: Flow simulation and experimental validation

“…The isothermal resin impregnation in the dry porous preform during VI is considered as Newtonian fluid flow in a porous medium, which is governed by the created pressure gradient between the inlet and outlet. 5,6,35,36 Considering gravity and isothermal resin flow in a homogenized porous preform, the governing equation takes the following form…”

“…Similar to Richards’s approach of transient porous media flow, the realistic representation of incompressible resin flow during infusion and considering the temporal availability of pore space (φ=1−Vf) in a control volume has been modeled using continuity equation (6). 4,5,53 It has been assumed that complete saturation of the preform means both the saturation of channel and fiber tows…”

“…During infusion, the spatio-temporal pressure gradient in the preform drives the flow front toward the outlet port. 4,5 The presence of a flexible vacuum bag on top and the saturation level in the porous preform creates the spatio-temporal variation in compaction pressures, fiber volume fraction (Vf), and permeability. Three saturation regions appear locally, corresponding to the associated saturation level: fully saturated, partially saturated, and the dry areas near the flow front.…”

“…Correia et al 6 proposed a 1D analytical model to predict the pressure profile, fill time, thickness variation, and fiber volume fraction for a predetermined steady incompressible flow and used the same for VI. However, Adhikari et al 5 and Yenilmez and Sozer 12 have incorporated the time-dependent relation of preform saturation with the spatio-temporal variation of Pcomp, Vf, and permeability tensor [ K ] to represent VARTM in a more realistic way ensuring complete saturation with low void content.…”

“…Vila et al 7 have incorporated the level set method to the coupled VI continuity model and Darcy’s momentum balance to model the VI and predict the location of flow front during infusion. Adhikari et al 5 proposed the level set 33 approach coupled with spatio-temporal preform compaction pressure Pcomp, Vf, and updated permeability to predict the instantaneous flow front location during VI without HPM. Later, the level set–based VI with HPM on top was modeled using a two-layer HPM and preform with the spatio-temporal variation of Pcomp, Vf, and permeability to predict the instantaneous location of flow front from both the top and bottom layers of the preform during infusion.…”