Design Optimization On Electromagnetic Scatter Property Of Low Observable Aircraft Wing Structure

The low observable (LO) structure is a kind of structures which consist of skin and varieties of internal materials, and has low radar cross section (RCS) with the considerations of stress and other requirements. It can comprise of diversified materials including coating, structural absorbing material, conventional compsite, and metal etc. Since the aircraft components has some room under the skin with the particular shapes, we can design the LO structures by structure arrangement and material application, which still meet requriements of shape, structural load and weight etc. LO structure has been playing an important role in the design of stealth vehicles. In this paper, two types of the LO wing structures are proposed for a low observable unmaned air vehicle. But numerical simulation of electromagnetic properties scattering for such wing structures is a challenge because the wing structures consist of different materials having different electric and magnetic properties. The paper presents the applications of the finite difference time domaim (FDTD) method to the numerical simulation of electromagnetic scattering fo the LO wing structures, and its calculated results. The reslults demonstrate that the RCS of those two types of wing structures is reduced substantially compared to conventional wings, and the graphite-embeded formed polystyrenes have major contribution on the RCS reduction of two wing structures. The electromagnetic parameter and geometrical feature has large effect on RCS of LO structure and need carefully design. To reduce compute time, this paper optimize those material and geometrical parameters using surrogate model which mainly include experiment design and approximation approaches. The results of numerical simulation and optimization is helpful for LO structure design.