Repairing sharp delamination cracks in CFRP through capillary action of acetone-diluted resin solution

Shape delamination cracks in carbon fiber composites were successfully repaired utilizing the capillary action of acetone-diluted resin solutions (without hardener). Resin pre-coating (RPC) solutions with 5, 10, 15, 30 and 45 wt% resin were tested and their repair effectiveness were compared. Resin curing inside narrow delamination cracks was achieved by applying the normal resin/hardener mixture at the open delamination edge so the hardening process could take place inside the resin-filled delamination cracks with time. Compressive tests were performed after 7, 21 and 42 days of repair to study the influence of curing period. The edge delamination was introduced through light impact at the edge of CFRPs panels. Compressive failure loads after repair showed that the 30 wt% of RPC solution yielded the most favorable repair result for the 7-day curing time. With 21- and 42-day curing times, even the least favorable repair condition of 5 wt% of the RPC solution produced significantly improved repair results. X-ray scanning was used to reveal the internal delamination before and after repair.