Mechanical properties of periodic rectangular tube sandwich structure subjected to out-of-plane impact compression loading

Owing to its unique deformation form, negative Poisson’s ratio sandwich structure has attracted significantly widespread interest, especially in the impact protection field. However, inferior mechanical properties severely limit their practical applications. To enhance its mechanical properties, a new type of periodic sandwich structure of rectangular tube was designed and fabricated, and the structure presents negative Poisson’s ratio characteristic under out-of-plane impact compression load. To evaluate its mechanical properties, the deformation form and equivalent yield strength of the periodic rectangular tube sandwich structure were obtained through the split Hopkinson pressure bar (SHPB) experiment. A numerical model of the different wall thicknesses of periodic rectangular tube sandwich structure (PRTSS) was established, and the accuracy of the model was verified by comparing it with the deformation form and equivalent yield strength obtained from experimental results. The results show that with the increase of rectangular tube wall thickness in PRTSS, the equivalent yield strength increases, and the equivalent yield platform strain decreases. Moreover, through the simulation results under four different strain rates, it is obtained that the equivalent yield stress of PRTSS increases with the increase of strain rate, and the straining length of the equivalent yield platform decreases with the increase of strain rate. The effect of wall thickness and strain rate on PRTSS was analyzed, which provided certain guiding significance for the application of the structure in the field of impact protection.