Crushing performances of Kirigami modified honeycomb structure in three axial directions

Abstract

A novel Kirigami (cut and fold) modified honeycomb structure is proposed in this study, aiming to reduce the initial peak force under out-of-plane crushing while maintaining the high energy absorption capacity, as well as increasing the in-plane crushing resistance. Three aluminium hexagonal honeycomb structures: standard honeycomb (HC), sheet reinforced honeycomb (RHC), and Kirigami modified honeycomb (KHC) structures are prepared and tested under quasi-static compression in three axial directions. The compressive properties of the proposed Kirigami modified honeycomb are compared with standard honeycomb and reinforced honeycomb in three axial directions. Numerical method is employed to adjust the wall thickness of HC so that its relative density is the same as RHC and KHC for fair comparisons on the crushing performances. Numerical model of standard honeycomb (HC) is calibrated and updated with the adjusted wall thickness to compare with the test results of reinforced and Kirigami modified honeycomb structures of the same relative density. The KHC demonstrated significant improvement on energy absorption capability as compared to the other two honeycombs in all three axial directions. Under out-of-plane crushing, KHC does not develop an initial peak force, while its average crushing resistance remains at a similar level as RHC, and is 17.6% higher than that of HC. Under the in-plane 1 compression, the average crushing resistance of KHC is around 5.2 and 7.5 times of that of HC and RHC, with an even lower uniformity ratio. The KHC shows a moderate improvement in crushing resistance in in-plane 2 direction, compared with the other two honeycombs. These results demonstrate the significant improvement of Kirigami modification on the crushing performance of honeycomb structures.