Modelling the Permeabilities of Dry Filament Wound Cylindrical Reinforcements for RTM Simulation

The production rate of filament wound composites can be improved by using the resin transfer moulding (RTM) process on dry filament wound reinforcements. Finite-element simulation of the resin flow in the porous dry fibre preform is needed to understand and improve the RTM process and to lower development time and cost. However, in a filament wound preform, the fibre volume content and the stacking sequence related to winding angles vary with geometry. This paper presents a new and simple modelling approach which quickly predicts the local principal directions and values of the permeabilities of a dry filament wound preform. In dry filament winding, dry unidirectional fibres are wound on a mandrel so that each element in the RTM simulation contains a multidirectional stacking. Thus, the model uses experimental permeabilities of a unidirectional stacking to predict the permeabilities of a multidirectional stacking for each element. Comparisons between calculated and experimental permeabilities of flat multidirectional stackings show a nesting effect on the permeabilities of the unidirectional stacking used as model input. A calculation method to recalibrate the input permeabilities of the dry unidirectional tape, based on measurements with minimal nesting, is offered. Better predictions are then obtained. The absolute percentage changes with experimental values were limited to 63.9% and 103.6% on in-plane and out-of-plane permeabilities, which had an order of magnitude of 1 × 10−12 and 1 × 10−13, respectively.