Abstract: Two methods to design the global stiffness of a high aspect ratio wing are introduced, i.e., the beam-frame model aeroelastic optimization method, and the three-dimensional optimization model conversion method. Taking a high aspect ratio wing as an example, rationality of the two methods is proved. Based on the beam-frame model, the global stiffness of the model main beam is designed by the first method using aeroelastic optimization. Because of its modeling simplicity and calculating efficiency, this method can be applied to the concept and primary design stage, though the precision is not high enough on account of its insufficient consideration of constraints. Based on the three-dimensional model, the global stiffness of the wing is designed by the second method using aeroelastic optimization and engineering beam conversion. The design stiffness by this method is closer to the actual critical case which takes into consideration the strength constraints, aeroelastic constraints, and process constraints. This method can be used in the primary design stage when some structure data is obtained; however, it has lower efficiency due to its high requirement of structure data and structure modeling. Through calculating and comparing the results, the consistency and engineering practicability of the stiffness distribution by the two methods are verified. Compared with the conventional estimation method, the two aeroelastic optimization methods are more reasonable.

Key words: aeroelastic, wings, stiffness design, optimization design, engineering method