Study on Equivalent Modeling Technology of Helicopter Complex Skin Structure

In recent decades, composite materials have been used in a large number of aircraft applications due to their light weight and high temperature resistance. However, due to the fact that the electromagnetic properties of composite materials are far less than those of pure metals, this poses a challenge to the design of the electromagnetic shielding performance of the complete machine. The current study is rarely to consider the exact structure of skin material. Besides, the exist method can not be applied to the electrically large size airplane model. To overcome these problems mentioned above, the equivalent modeling technology of helicopter complex skin structure is studied. Based on the vertical cross-over structure of carbon fiber prepreg and the multi-angle laying of the skin, the skin structure of the complex helicopter body is equivalent to an isotropic single-layer plate structure with electromagnetic parameters varying with frequency. By measuring the transmission coefficient and reflection coefficient of the typical skin structure of the helicopter, the complex permittivity and the complex permeability of the helicopter were calculated, and the equivalent model of the skin structure was established in the HFSS. Finally, the shielding effectiveness of the skin was measured by the flange coaxial device, and compared with the shielding effect in HFSS, the accuracy of the model was verified.