Sandwich structures, which consist of two thin, stiff face sheets separated by a lightweight, thicker core, have very important applications in the naval and aerospace industry due to its high specific strength, high specific stiffness and energy absorption capabilities. Lattice sand-wich structures can provide a good prospect for vibration and noise reduction owing to its open topology and design of core configuration. Based on bionic design, a gradient configura-tion of pyramid lattice sandwich structure was proposed in this paper by changing cross-section size of core bars of structures. The relative density of each core layer is changed while the total weight of structures is kept constant. Four multilayer gradient pyramid lattice struc-ture configurations were designed here and five models with different gradient ratio for each configuration were suggested. Commercial finite element software ABAQUS/Explicit was used to simulate vibration of the developed models, and the first to sixth order natural fre-quencies of each model were determined. The vibration characteristics of the gradient lattice sandwich structures were studied by comparative analysis.
