Multifidelity Design of Structurally Embedded Waveguides

Abstract

Slotted waveguides embedded in aircraft skin panels may not support a buckling load without failure in the copper waveguide due to stress concentrations created by the corners of the slots. To create designs strong enough to avoid compressive failure before buckling instability, an initial offset in the copper waveguide may be added so that the supporting skin cover and backplane take additional load to prevent failure at the waveguide slot corners. A structural model is developed to include a gap in the eigenvalue analysis through a prestress term, and subsequently to account for the gap in an optimization procedure. Additionally, a curve fit is used to account for local buckling modes that reduce the plate buckling mode of the final panel design. These factors combine to allow for a low-fidelity model to account for the gap and local buckling without the need for a high-fidelity model using plate or contact modeling. This low-fidelity model is then run through an optimizer, producing designs that are stronger and/or lighter for a fraction of the computational cost of prior high-fidelity models.