Research On Bio-inspired Curved Lightweight Sandwich Structure Design And Mechanical Property

Beetle's elytra is a biological material with special structure and function, which protect against external damage, and in possess of light weight and high strength and so on. Recently, this material is one of the bionic objects to research the new kind of light weight, high strength and multi-functional structural material.Beetle's elytra has a strong bearing capacity, not only related to the internal microstructure, but also on its unique arched surface. In this paper, a three-dimensional laser scanner smart SCAN is applied to measure the geometric surface, and obtained the point cloud data of beetle's elytra. Extract the outline data of beetle's elytra and import the data into Matlab, by using the least square method for data modeling and mathematical model. Then CATIA reverse engineering technology was used to reconstruct the elytra surface. Based on surface reconstruction and the microstructure of the cross-section of the beetle's elytra, a kind of bio-inspired curved lightweight sandwich structure was designed and built.The finite element model of bio-inspired curved lightweight sandwich structure was established, and bending mechanical properties was analyzed by using the finite element method.The bending force-displacement curves were obtained. In order to verify the correctness of the finite element analysis, a three-point bending experiment on the structure samples was carried by using the universal testing machine, and the contrast results between the finite element analysis and experiment show good consistency. At the same time, the mechanical properties of the bio-inspired curved lightweight sandwich was compared to that of plane structure and solid curved panel with FEM, the results show that the bio-inspired curved lightweight sandwich structure has superior mechanical properties. Then the compressive mechanical property of the structure was analyzed with FEM.The impact mechanical property was analyzed with FEM. The finite element models was established, including impact hammer and the bio-inspired curved lightweight sandwich structure. The dynamic response of the bio-inspired curved lightweight sandwich structure under impact load was simulated, solving the stress distribution and the impact energy of the whole process. Then the drop hammer impact experiment was carried to obtain the impact energy. The finite element results with the experimental results were compared to verify the accuracy of the finite element analysis.Finally, the parametic modeling of the bio-inspired curved lightweight sandwich structure was established, and quality and maximum equivalent stress were as multi-objective optimization goal, to determine the optimal parameters of the structure. The optimized structure of the maximum equivalent stress was reduced by 9.9% and the total mass was reduced by about 2%.At the same time, energy absorption ratio improved by 7.5%.