Research on three-point bending performance of hollow-core rod pyramidal gradient lattice sandwich beam

In contemporary engineering, there is an escalating demand for higher mechanical properties in sandwich beams. In this paper, we propose a novel lattice sandwich beam with a hollow-rod pyramid gradient structure (PGLSB) that exhibits superior three-point bending performance. The ultimate flexural capacity of the PGLSB serves as the index to evaluate the flexural performance of the structure. Theoretical prediction and numerical simulation are employed to examine the impact of the gradient coefficient, initial outer diameter, and wall thickness of the core rod on the three-point bending performance of the structure. Furthermore, the bending ultimate specific carrying capacity (fv) is adopted as the optimization objective, and the genetic algorithm (GA) and response surface method (RSM) are applied to optimize the structural parameters. The findings reveal that the gradient coefficient (q), initial outer diameter (D1), and thickness of the core rod (tc) have a considerable influence on the bending ultimate specific carrying capacity (fv) of the structure. The optimized sandwich beam displays a substantial improvement in the ultimate specific carrying capacity compared to the conventional sandwich beam. In conclusion, this study on the three-point bending performance of the PGLSB may guide the optimal design of lightweight lattice sandwich structures.