An easy-to-implement self-healing smart design for increasing impact strength and crashworthiness resistance of honeycomb sandwich structures

In this paper, the dynamic compression impact response of an aluminum honeycomb core filled with open-cell foams impregnated with self-healing liquid agents was investigated experimentally. Samples were subjected to a variety of impacts in order to determine healing time and self-healing performance. Three different sandwich specimens were developed to evaluate the effectiveness of self-healing. The sandwich specimens are designated as B (empty honeycomb core cells), S (only open-cell soft polyurethane foam-filled honeycomb core cells), and self-healing agent (SHA) (open-cell soft polyurethane foams impregnated with liquid self-healing agents). The test results were presented by considering the crashworthiness and healing efficiency criteria, and the impact characteristics of the samples were compared related to these criteria. After testing, the results demonstrated that the self-healing agent specimens had much fewer buckling deformation and displacement than their counterparts. Significant improvements were achieved in healing efficiencies and crashworthiness evaluation criteria. The peak load and the energy needed to attain peak load are considered healing efficiency criteria. Self-healing agent specimens reached 29.7% and 12.9% more peak loads, and in the energy absorbed up to peak loads 140% and 34.9% higher values than the B and S sandwiches. In the same samples, crushing strain features were acquired as 50% versus 66%, indicating less displacement in self-healing agent specimens than counterparts. The results indicated that an aluminum honeycomb sandwich structure that can heal itself after damage and recover impact characteristics remarkably could be produced practically.