(171a) Patch Repair of Composites Using Dielectric Barrier Discharge Induced Heating and Curing

Here, we demonstrate a novel methodology of repairing cracks or damages in carbon fiber reinforced composites (CFRCs) using Dielectric Barrier Discharge (DBD) induced heating and curing. This study involves the use of a epoxy-impregnated carbon fiber patch or prepreg, which is laid upon the cracked or affected area of a composite in order to eventually mitigate the damage. The DBD applicator generates an electric field plasma; conductive carbon fibers heat up when exposed to this plasma, and the heat is transferred to the surrounding epoxy, thus curing the patch. This cured patch acts as a structural additive to the damaged part, significantly improving its mechanical properties and rendering it fit for further use. Differential Scanning Calorimetry (DSC) experiments show that the glass transition temperature and degree of cure of the exposed patch can be controlled by adjusting the target temperature and residence time of the DBD-induced heating process; patches of varying initial degrees of cure allow for repairs in damaged composites with varying curvatures. Furthermore, the mechanical properties of damaged and repaired samples were compared using tensile testing; a ~78% increase in ultimate tensile strength of the DBD-repaired sample was observed compared to the damaged sample. This study establishes Dielectric Barrier Discharge as an energy efficient, out-of-oven methodology for damage repair in carbon fiber composites.