民用飞机壁板蒙皮及长桁布置结构优化设计

Optimization Design of Panel Skin and Stringer Configuration for Civil Aircraft

机身壁板是飞机结构设计的重要承载组件,轻量化、高效率、共通性设计及优化是民机设计关注的重点。首先提出一种耦合ABAQUS的Buckle分析及ISIGHT优化的设计方法,利用自编子程序获取ABAQUS屈曲特征值,将特征值输入ISIGHT中计算临界屈曲载荷,同步更新变量参数及ABAQUS文件并提交计算,迭代分析直至优化流程结束。采用上述方法考虑轴向压缩载荷情况,以壁板整体重量最小为优化目标,疲劳应力值为约束条件,对单曲度金属机身壁板的蒙皮厚度,长桁数量及长桁截面厚度等几何参数进行优化。在满足壁板结构承载能力及总重量最小条件下,综合考虑结构载重比,临界应力及壁板加筋比,对比分析出一组最优参数,并与工程算法结果对比吻合程度较好,两者相对误差为3.73%。该优化思路实现FEA平台与优化工作一体化,可用于复合材料壁板设计及结构件减重优化工作,一定程度上可缩短零组件设计周期。

Aircraft fuselage panel is one of the important load carrying members in structure design. The characteristics of lightweight, high efficiency, commonality and optimal design for civil aircraft have been attracted much attention in the past decades. In this study, an optimization methodology coupling ABAQUS buckle analysis and ISIGHT optimization was presented. The buckle eigenvalue was extracted from linear buckle analysis in ABAUQS using subroutine firstly, which was then input into ISIGHT for critical buckle load calculation. Meanwhile, the optimized parameters and ABAQUS input file were updated simultaneously for iterative analysis subsequently until the optimization procedure was finished. By utilizing the proposed method, the optimization study considering minimal weight as objective and fatigue stress as constraint respectively for metallic fuselage panel design was conducted under axial compression. The panel skin thickness, stringer number and cross section thickness of stringer were taken into account for optimization. Finally, the ratio of load-carrying to weight, critical stress and panel stiffening ratio were evaluated comprehensively to obtain optimal geometrical parameters both satisfying structural load carrying capacity and minimal weight. Besides, the optimal results were in reasonable agreement with theoretical results with a relative error of 3.73%. This method achieves the platform integration of FEA and optimization, which can provide further guidance for weight saving design of structural component and composite panel, therefore leading to time saving for aircraft component design in a certain degree.