Blast Resistance Simulation And Multi-objective Optimization Of Multilayer Pyramidal Lattice Sandwich Panel

Owing to its advantages of lightweight,high specific strength,high specific stiffness and designability,pyramidal lattice sandwich panels have great potential in the field of modern military protection.Sandwich panels on the battlefield are usually attached to the bottom of the passenger compartment to protect passengers from explosive weapons.Compared with single-layer lattice sandwich panels,multi-layer lattice sandwich panels have better blast resistant protection effect,but the deformation of multi-layer gradient sandwich panels under explosive impact varies greatly.Based on this research background,dynamic explicit finite element simulation technology is used to study the dynamic response under blast loading of the gradient and non-gradient multi-layer pyramidal lattice sandwich panels with different structural configurations.The influence of key geometric parameters on the blast resistance performance of the two types of sandwich structures is analyzed.On this basis,muti-objective optimization on the blast resistance performance of the above two types of structures is carried out.In this paper,finite element analysis software HyperMesh is used to establish a simplified core model with beam element instead of solid element,and then a finite element model of non-gradient multi-layer pyramidal lattice sandwich plate is built.The accuracy of the method is verified by comparing with the experimental results in the literature.On this basis,the deformation and energy absorption of the above finite element model under the impact of explosive load are analyzed.The simulation results show that the energy absorption characteristics of the non-gradient reference pyramidal lattice structure are limited due to the large difference of core deformation among layers.Therefore,it is necessary to analyze the parameters that cause the difference of deformation and energy absorption between gradient sandwich panels and non-gradient sandwich panels.In this paper,the impact of key geometric parameters on the blast resistance of gradient and non-gradient multi-layer pyramidal lattice sandwich structures is analyzed by taking the specific energy absorption and maximum deformation of backplane as evaluation indexes.Among them,the parameters of gradient lattice structure include the thickness of each layer plate,the height of each layer core and the cross-section size of each layer core web;the parameters of non-gradient lattice structure include the thickness of panel and the relative density of cells.In order to improve the blast resistant performance of sandwich panels,taking the specific energy absorption of structural planes and the maximum deformation of backplane center as optimization objectives,and taking several geometric parameters which have great influence on the performance of multi-layer sandwich panels as variables,the RBF response surface proxy model and the NSGA-II genetic algorithm are used to optimize the gradient and non-gradient multi-layer pyramidal lattice sandwich panels respectively,and the Pareto optimal non-dominant solution sets are obtained.Furthermore,considering load uncertainty,the reliability optimization design of the structure is carried out.Comparing the optimization results of two kinds of multi-layer sandwich panels under different explosion equivalents,it is found that the blast resistant performance indexes MaxD and ASEA of sandwich panels under single explosion load are contradictory;with the increase of explosion equivalents,the values of ASEA and MaxD will increase simultaneously;the reliability of ideal optimal solution under single explosion condition is poor,and load uncertainty is introduced to satisfy the reliability design results.When the maximum instantaneous displacement of the center of the backplane is small,the gradient sandwich panel has greater energy absorption advantage;on the contrary,the non-gradient sandwich panel has more potential.