Structural Optimization of Internal Structure of Aircraft Wings with Curvilinear Spars and Ribs

摘要

A new framework for optimization of the internal structure of transport aircraft wings having curvilinear spars and ribs (SpaRibs) is described. SpaRibs are parameterized by third-order B-splines with constraints on the starting, ending, and various control points. A broad range of SpaRibs topologies can be created using a limited number of parameters. For local size optimization, panels are generated from the wing finite element model by an algorithm that is independent of the nodal coordinates and the order in which the elements are distributed, and which can be used for a broad range of aircraft wings. The local panel thicknesses are optimized to satisfy buckling and stress constraints of the wing using an algorithm that increases the thickness of the panels that are found to be vulnerable to buckling or wherein the stress is higher than the maximum permissible stress. This algorithm has been integrated with the particle swarm algorithm to optimize the SpaRibs topology for multiple objectives (weight and flutter velocity). The code is demonstrated by optimizing the internal structure of the NASA Common Research Model wing model with SpaRibs considering stress and buckling constraints at trim condition at Mach number equal to 0.85 for two different angles of attack (-2 and 6 deg).