The self-healing sandwich panel: Production of epoxy based self-healing capsules, self-healable sandwich panel development, and experimental measurement of self-healing performance

• A novel macro-capsule production system was developed. • A sandwich panel was formed by filling macro-capsules with healing agents. • Quasi-static compression and high strain rate impact tests were performed. • The performances of healing agents were examined experimentally and visually. • The contribution of self-healing macro-capsules to the amount of energy absorbed was observed. In this study, macro-capsules were developed by encapsulating epoxy and hardener agents for macro-level structural healing. Obtained macro-capsules were placed into an aluminum honeycomb core to obtain self-healable sandwich structures. In principle, the aim was to self-repair damaged sandwich structures by breaking the macro-capsules with the resulting leak of healing agents into the cells of the core. The developed sandwich structure was subjected to repetitive quasi-static compression and high strain rate compression impact tests. According to the experimental results, the sandwich structure gained a very effective self-healing facility and maintained this property under multiple repetitive loadings. In addition, the energy absorption capacity of honeycomb aluminum sandwich structures was increased by approximately 80% under both quasi-static and high-speed impact loads.