Blast Resistance Simulation And Multi-objective Optimization Design Of 3D Re-entrant Honeycomb Sandwich Panels

Nowadays,with the rapidly changing of modern wars and conflicts,improvised explosives,landmine bombs,etc.have become the main threat to the loss of personnel and materials.In addition,the power of explosive weapons is further enhanced,so it is especially important that the blast resistant performance of military armored vehicles needs to be improved.The sandwich composite armors with excellent blast resistance and light-weight performance have received extensive attention and research in the field of explosion protection for military vehicles.Among them,the Negative Poisson's Ratio structure is regarded as the ideal material for the core part of the sandwich panel because of its higher specific stiffness and specific strength,superior energy absorption performance.In this study,a novel three-dimensional re-entrant honeycomb structure is applied to the core of sandwich panels,and the dynamic response and blast resistant performance of the three-dimensional re-entrant honeycomb sandwich structures under blast loading were simulated by finite element method.In addition,the influence of some structural key parameters on the overall blast resistance was investigated and the multi-objective optimization design of the sandwich structures was performed.Firstly,the specimens of three-dimensional re-entrant honeycomb structure were fabricated by additive manufacturing or laser cutting technology combined with the interlocking assembly method.Their Negative Poisson's Ratio effects and the compression deformation modes were studied by quasi-static compression experiment and finite element simulation methods.The results showed a great consistency between the experimental process and finite element analysis,so the subsequent simulation and optimization design can be performed based on this finite element model.Secondly,the finite element models of the three-dimensional re-entrant honeycomb sandwich panels were established by using HyperMesh and LS-DYNA software.In this paper,an effective simplified beam element modeling method was proposed to establish the core part the sandwich panels.The numerical simulation was carried out to study the overall blast resistance of the three-dimensional re-entrant honeycomb sandwich panels with different material configurations under blast loading.The results showed that the type of sandwich panel with the lower stiffness material of upper face sheet and the harder material of back face sheet has a preferable comprehensive anti-explosion performance.In terms of the core's features,although the "harder" core can ensure an ideal deformation intrusion of the back face sheet,the "soft" core can absorb more blast energy through the deflection.Then,the structural parameters are divided into two categories: external parameters and geometric parameters.The effects of these key parameters on blast resistance of the sandwich panels were quantitatively analyzed.Afterwards,in order to obtain the optimal design of blast-proof structures,the multi-objective optimization design of the geometrical parameters was carried out to realize the maximum energy absorption(ASEA)and minimum deformation(MaxD).It was found that there are contradictions between the two optimization objectives,and it is necessary to identify the optimal designs according to actual needs in the Pareto optimal set.Finally,the functionally graded concept was introduced to design the layered graded sandwich panels.The influence of the various gradient arrangements of struts' thickness on the blast resistance was investigated and analyzed.The simulation results denoted that the layered graded arrangements have a significant effect on the structural blast resistance of the three-dimensional re-entrant honeycomb sandwich panels.Compared with the equivalent uniform thickness three-dimensional re-entrant sandwich panel,the panel with alternating arrangements of graded core has the best performance against explosive loading.At the same time,the concept of graded core provides a larger design range to further enhance the blast resistance through the multi-objective optimization for graded struts thickness.