混合遗传算法在气动弹性多学科优化中的应用

利用遗传/敏度混合优化算法对复合材料前掠翼飞机进行气动弹性剪裁设计研究.在满足强度、位移、升力效率、副翼效率、发散速度和颤振速度等约束条件的前提下,以机翼复合材料蒙皮铺层的厚度为设计变量,对蒙皮进行重量最小化设计.研究表明,在飞机结构初步设计阶段单纯使用基于敏度的优化算法,很难满足设计上的要求;使用遗传/敏度混合优化算法可以取得较好的结果,该方法适用于飞机结构初步设计.还研究了偏轴角对优化重量的影响.分析结果显示,对于文中所研究的这类蒙皮使用由0°、90°和±45°纤维组成的铺层的复合材料前掠翼飞机,在满足多个约束条件的前提下,其优化重量对于偏轴角的变化相对不敏感.

Application of hybrid genetic algorithm in aeroelastic multidisciplinary optimization

The genetic/sensitivity-based hybrid algorithm was used for the design studies of aeroelastic tailoring of a forward-swept composite airplane. The design objective is to minimize the weight of skin. The ply-thicknesses of wing skin were selected as design variables. The constraints were strength, displacement, lifting efficiency, aileron efficiency, divergence speed and flutter speed. The studies demonstrate that it is difficult to meet design requirements in preliminary design of aircraft structure when sensitivity-based algorithm is used along. The genetic/sensitivity-based hybrid algorithm could outperform sensitivity-based algorithm operating alone. The hybrid algorithm is suitable for preliminary design of aircraft structure. The effect of ply-orientation on optimized weight while satisfying the above multiple constraints was discussed. The results indicate that the optimized weight of the forward-swept composite wing is relatively insensitive to ply-orientation of skin when skin lay-up consists of 0°, 90° and ±45° fiber directions and wing is subjected to multiple constraints on static constraints, static aeroelastic constraints.