Enhanced the impact resistance by gradient face-sheet design of a sandwich structure

Abstract

Sandwich structure has been designed to reduce the impact damage of the stress waves. However, the existing work focuses on the optimization of sandwich cores while the face-sheet structure is seldom improved. Here, we used the impedance matching theory to design a negative gradient face-sheet sandwich structure with excellent stress wave attenuation performance. Owing to stress wave attenuation form a high impedance to a low one, the negative gradient face-sheet sandwich structure shows a low peak stress of 5.51 MPa, and the average transmission peak stress is 2.69 MPa. The gradient face-sheet structure changes the compressive deformation behavior; thus, the energy absorption performance of the negative gradient face-sheet sandwich structure increases to be 1311.8 kJ/m3 and the specific energy absorption reaches 1072 J/kg. Finite-element methods further demonstrate the overall sandwich structures can be enhanced through alleviating the failure of sandwich core by a gradient face-sheet structure. This work provides a paradigm for the design of sandwich structures with high energy absorption performance.