Permeability characterization of stitched carbon fiber preforms by fiber optic sensors

The in-plane and through thickness permeability of unidirectional stitched carbon fiber preforms have been
determined through vacuum infusion tests. The impregnation of various dry preforms with different stitching characteristics
has been monitored by fiber optic sensors that have been stitched together with the dry tow to manufacture the dry preform.
The experimental infusion times have been fitted by a numerical procedure based on Finite Element (FE) processing simulations.
A good agreement between the numerical and experimental infusion times has been found demonstrating the potentiality
of the fiber sensor system as suitable tool to evaluate impregnation times and permeability characteristics.