Study On Electromagnetic Wave Absorbing Performance Of Quasi-honeycomb Core Structure

As a typical structural wave-absorbing material,honeycomb structure has been widely used in the field of stealth because of its dual functions of bearing and absorbing.At present,most of the researches on the microwave absorbing ability of honeycomb structure are focused on hexagonal honeycomb structure.With the increasing requirement of engineering application on load-bearing and wave-absorbing performance,it is necessary to study the wave-absorbing performance of new honeycomb structure.In this paper,based on the existing research results,the quasi-honeycomb core structure is studied by theoretical analysis and numerical simulation.The main research contents are as follows:(1)Calculation of equivalent electromagnetic parameters of quasi-honeycomb sandwich absorbing structure.Based on the homogenization theory and strong disturbance theory,the equivalent electromagnetic parameters(permittivity and permeability)of the quasi-honeycomb core absorbing structure are derived,and the reflectivity curves of the equivalent model and the original model are obtained by simulation analysis,the accuracy of the formula for calculating the equivalent electromagnetic parameters is verified.Finally,the influence of structural parameters on the equivalent electromagnetic parameters is analyzed.(2)Study on wave-absorbing performance of quasi-honeycomb core structure.The finite element model of quasi-honeycomb core structure with absorbing core and absorbing coating is established,the effects of a series of structural parameters,such as cell-like size,height,wall thickness and coating thickness,on the microwave absorbing properties of the two structures are analyzed.For the quasi-honeycomb core structure filled with absorbing core,the reflectivity of the structure is less than-10 d B in the range of 6.57-7.33 GHz and 8.73-9.04 GHz in the frequency range of 2-18 GHz,the reflectivity of the structure is less than-8d B in the range of2.53-3.53 GHz and 4.29-18 GHz.For the quasi-honeycomb core structure with impregnated absorbing coating,the reflectivity of the structure is in the range of 2.60-5.87 GHz and 8.80-18 GHz when the reflectivity is less than-10 d B.Finally,the gradient distribution of absorbing coating is presented,and the range of reflectivity of the gradient structure is 3.2-18 GHz,which is less than-10 d B,the effective absorption bandwidth is 2.33 GHz larger than that of the uniform structure without gradient design.(3)Design of multi-layer composite quasi-honeycomb core structure and study on its microwave absorbing performance.The multi-layer structure of quasi-honeycomb core structure is designed,and the design parameters are n,the total height D of the structure and the gradient factor M of the thickness of the absorbing coating of the adjacent two-layer structure.The final design parameters are n = 3,D = 15 mm and M = 0.03 mm,the multilayer structure has good absorbing performance.The minimum reflectivity is-31.81 d B in the range of 2-18 GHz,the average reflectivity is-18.96 d B,the range of reflectivity less than-10 d B is 2.94-18 GHz,and less than-20 d B in the range of 10.21-18 GHz.The design of multi-layer structure is more advantageous than single-layer structure to improve the microwave-absorbing performance of honeycomb-like sandwich structure.