| Among many new materials and structures in the field of modern armor protection, metal lattice sandwich structure rose to prominence and would expand the application to other areas owing to its lightweight, high strength and specific stiffness characteristics, excellent energy absorption and buffering capability, This paper took it as the object and investigated the dynamic responses of pyramidal lattice sandwich panels under blast load and projectile impact load by explicit finite element method. Moreover, multi-objective optimization of the pyramidal lattice sandwich panels were studied.Firstly, two kinds of simplified FEA models used to simulate the lattice core were proposed. The one is simplified shell element model, the other is simplified beam model. The former can be used for anti-blast performance analysis and optimization of PLSP, and the latter can be applied for penetration condition. Based on the simplified model, parameter analysis with single variable method were adopted in changing the front and back face-sheet thicknesses, core thickness, length of square core truss section as well as standoff distance (SoD) between the panel and the charge. Hence, aimed to improve the anti-blast properties of the sandwich plate and based on the surrogate model method, multi-objective design optimization (MDO) of the PLSP was studied with certain and uncertain blast load, which the design variables were key structure parameters of sandwich panel. The study found that two anti-blast performance evaluating indicators were not positive correlation. Optimal design should be selected in the obtained Pareto Front according to the needs. Besides, a robust design method of sandwich panel under uncertain blast load was provided.Secondly, aluminum alloy was added into the sandwich panels, thus the steel and aluminum composite sandwich panels with different material configuration were formed. Studied with dynamic response of four kinds of PLSP under blast load, then normalized blast resistant performance of four kinds of sandwich panel and found that four sandwich panels have their own advantages and disadvantages. The optimized results showed that three kinds of sandwich panels would have become the optimal solution set of different stages, and one of them was not dominant; Hybrid sandwich panels provided much more choices with optimal performance.In addition, explosion is often accompanied by the occurrence of projectile penetration. The anti-penetrating performance of PLSP was studied numerically, using the shell element model to simulate. Its accuracy was verified by the experimental results. This paper studied the penetrating process with three kinds of incident position, explored its effect on the ballistic limit. The results showed that three situations have different deformation modes. Ballistic limit of PLSP depends on weakest incident position.Finally, simulation of the blast resistance of curved pyramidal lattice sandwich panels (CPLSP) was analyzed. The effect of radius of curvature on the anti-blast properties of sandwich panels was emphased. Also, the results show that the radius of curvature change would lead to the different deformation modes of sandwich panel and have a monotonic effect on ASEA and MaxD in the studied range. However, in the case of R tent to infinity (flat plate), the maximum deformation of the back plate decreased, so there was a maximum value point. Therefore, MDO of the CPLSP was launched. Compared with the original design, the anti-blast performance of the optimal design of Pareto Front was apparently improved. |
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