The importance of GA Optimization in Design Aircraft Strucuture

The skin layers of aircraft wings are produced with inherent geometric deviations from their manufacturing processes. These deviations hamper the alignment of the skin panels and consequently hamper their riveting to the wing ribs. Corrective weights are used to conform the skin panels to their correct shape before riveting. This book presents an algorithm for the optimal allocation and distribution of corrective weights on skin panels. The algorithm represents the deviated skin panels using non uniform rational B splines (NURBS) to take the free-form shape of the skin panel. It then divides yhe panel in to a number of shell elements, each subjected to a candidate corrective weight. The fixture clamping locations are simulated as boundary conditions for the skin panels, and then a finite elements analysis (FEA) of this shell element is then conducted to calculate the deformations in the nodes of the FEA model. The best set of candidate of corrective weights would be the one that will deform the skin panel to its original design. Therefore the above coupling between the free-form NURBS representation and the FEA is included in an optimization algorithm code.