针对大展弦比机翼总体刚度设计问题,提出了梁架模型气动弹性优化和三维优化模型折算两种设计方法,并以大展弦比机翼为例对两种方法的合理性进行了验证。前者基于机翼梁架式模型,利用气动弹性优化方法对其主梁刚度进行设计,其特点是建模简单、计算效率较高,可以在设计信息较少的概念和初步设计阶段使用,但由于约束条件考虑较少,设计结果相对粗略。后者基于机翼三维模型,利用气动弹性优化方法获得优化模型,再利用工程梁理论对优化模型进行刚度折算,获得机翼总体刚度分布,其特点是综合考虑了强度约束、气动弹性约束甚至是工艺约束,设计刚度最接近实际临界情况,可在有一定结构设计信息的初步详细设计阶段使用,但所需结构信息量较大,对结构建模要求较高,计算耗费相对较大。研究表明,基于两种方法设计的刚度分布具有较好的一致性和工程实用性。此外,与传统的经验公式推算方法相比,基于气动弹性优化手段的两种设计方法设计的刚度更趋合理。
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.
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