On The Study Of Electromagnetic And Shock Wave Property Of A Sandwich Vehicular Armour Plate With Composites

Armoured vehicle plays a very important role in transporting infantry for the mobile warfare capability and transportation of materials or supplies, et al, in the war. The stealth ability of Armored vehicles has been improved in order to adapt the development of anti-stealth technique with the development of the electronic detection technique. People realize the serious harm of blast wave caused by bomb to the human body. But anti-explosive feature of amoured vehicle should be enhanced. It is necessary to investigate the electromagnetic (EM) and shock wave mitigation capability of a novel sandwich armor panel in order to protect the vehicles and crew better.Maxwell's equations in this paper introduce the relationship between the electric field and magnetic field, field and field, field and medium in detail; The reflection and refraction characteristics of EM wave vertically incident monolayer and multilayer dielectric medium are deduced; The oblique incident EM wave on boundary surface is analyzed; The loss mechanism of the traditional absorbing material and the new absorbing material is discussed.The characteristics of sandwich structure are analyzed. It is found that sandwich structure has better resistance to bending deformation by comparing bending rigidity between single layer structure and sandwich structure. According to the law of conservation of energy and conservation of momentum, the transmission characteristics of shock wave in the sandwich structure are deduced.Based on the theory analysis and deduction of EM wave and shock wave, the armor plate sandwich structure prototype is established; this paper designs a novel lightweight sandwich plate, which both absorb EM wave and attenuate the shock wave transmission, and the core of which is functionally graded foams containing multiwall carbon nanotubes (MWCNT) at weight percentage of 5%. According to the analytical model, a parametric study is performed to investigate the effect of gradient pattern and the thickness of each dielectric layer on EM reflection coefficient and shock wave transmission coefficient. By the software interface of ISIGHT integrating MATLAB optimization program, a multi-objective optimization used NSGA-II is conducted to generate the optimal design. As a result, the electromagnetic reflection coefficient and shock wave transmission coefficient are reduced by 94.58% and 4.35% respectively, which indicate a good EM absorbing performance and shock wave attenuation performance.Finally, the coaxial airline hosting the electromagnetic absorber is simulated by using COMSOL MULTIPHYSICS, and the validity of the finite element model is verified by the experimental results. Then, a finite element analysis has been carried out to explain the mechanism of EM absorption. The results are consistent with theoretical analysis, and the results illustrate that MWCNT can stimulates the absorption of EM waves.