Analytical prediction of void distribution and a minimum-void angle in anisotropic fabrics for radial injection resin transfer molding

2D radial injection vacuum-assisted resin transfer molding experiments were performed using anisotropic plain-woven fabrics to determine the void distribution and the relationship between the void fraction and the resin flow velocity at arbitrary resin impregnation angles. The obtained void fraction values vary with the impregnation angle and velocity, while void formation is very difficult at the minimum-void angle oriented in neither the warp nor the weft direction. Moreover, the impregnation in the fabric microscopic structure is characterized by two patterns separated at the minimum-void angle. Based on the experimental results, a mathematical model for predicting the void fraction value at arbitrary impregnation angles and velocities and for calculating the minimum-void angle was developed. A comparison of the model predictions with the experimental results revealed a good agreement between them.