Analytic methods to predict resin pocket geometry around the microvascule in self-healing composites

Two analytic methods are presented to predict the resin pocket geometry around the microvascule in self-healing composites with microvascular networks. The bending strain energy is calculated on the fiber scale in one method (FSM), while is on the layer scale in the other method (LSM). For the FSM, several fibers in thickness direction are tied together to account for the bending stiffness increment caused by the interaction between the fibers. And for the LSM, a single ply is divided into several sublayers to account for the bending stiffness decrement caused by the sliding between adjacent fibers. Both analytic methods can provide the closed-form solution for the resin pocket width, and the analytic results agree well with experimental results. The physical consistency of two methods is proved. It is found that the resin pocket size depends mainly on ply angles of the plies close to microvascule, and the stacking sequence has some effect.