Research On Crashworthiness Performance Of Square Frustum Lattice Structure Based On Selective Laser Melting

The lattice structure has the properties of light weight,high strength ratio,high toughness,impact resistance and good energy absorption,and is widely used in aerospace,high-speed trains,ships,and many other engineering fields.In this paper,the flat-topped pyramid is used as the structural cell,combined with selective laser melting technology to fabricate the sample of square frustum lattice structure,and the in-depth and detailed discussion and research are carried out from the aspects of theoretical analysis,numerical simulation and experimental testing.The research contents of this paper are as follows:(1)The flat-topped pyramid with good stability is used as the structural cell,a new type of square frustum lattice structure is designed,and the theoretical prediction model of the mean crushing force is established.Then,based on the concept of light weight,Al Si10 Mg aluminum alloy powder is selected to prepare samples by selective laser melting.(2)The axial quasi-static and impact experiments of the lattice structure of the lattice structure are carried out,and the correction coefficient of the theoretical prediction model is proposed.It was found that,compared with the number of cells,the side-length ratio and the cell height has a more significant effect on the energy absorption capacity of the lattice structure under axial compression.Finally,the influence of the offset ratio of the axial load on the crashworthiness of the lattice structure is analyzed,and it is found that the crushing force under the offset load can maintain a small fluctuation with the displacement,and the maximum value of the stability index of the force-displacement curve does not exceed 0.20,and the forcedisplacement curve stability index phase under the offset load of 25%overlap ratio has a significantly higher value,the offset load with the overlap ratio of 40% and 60% absorbs the most energy per unit overlap.(3)The lateral quasi-static compression experiment is carried out on the lattice structure of the lattice structure,and the axial and lateral quasi-static compression comparison analysis is carried out with the common multicell structure commonly used in engineering and the multi-cell structure with origami pattern with better performance.In addition,the parametric analysis of the square frustum lattice structure under lateral compression is carried out,and finally the sensitivity comparison of the axial and lateral quasi-static compression of the square frustum lattice structure to the parameters is studied.Studies shown that the crashworthiness of lattice structures subjected to lateral compression loads is more affected by parameters than axial compression.Among them,the crashworthiness performance of lattice structures under lateral compressive load conditions is most sensitive to the side-length ratio among the structural parameters.