Development of a novel cyanoacrylate injection repair procedure for composites

In this study, a novel resin injection repair procedure and rig have been developed that have several advantages over current repair methods including a relatively low curing temperature and the use of common laboratory equipment. Cyanoacrylates (CAs) have been chosen as the repair resin due to their very low viscosity. Impact damage was introduced to carbon fibre epoxy resin specimens using a drop tower instrument. An impact energy of 20 J resulted in repeatable damage consisting of delaminations, matrix cracks and breakout where the plies close to the impacted surface were not fractured. Compression after impact testing was performed to evaluate the success of the repair procedure. Damaged specimens retained 45.1% of the ultimate compressive strength of pristine specimens. It was found that up to 92.4% of the compressive strength of pristine specimens was achieved by specimens repaired with a liquid CA using the developed repair procedure. Repaired specimens had similar damage tolerance to pristine specimens and displayed only minor decreases in compressive strength after fatigue loading.