插入式机翼下壁板对接附加弯矩研究

插入式机翼下壁板对接具有双剪传力稳定、疲劳性能好的优点，但其结构中心线在对接区变化明显，会带来附加弯矩。为尽量减小对接区的附加弯矩，提出了在建立飞机骨架模型时即优化中央翼下翼面外形面相对外翼下翼面的位置方法。基于插入式机翼下壁板对接结构的特点，阐述了对接结构偏心的来源和附加弯矩的形成；针对某A型飞机的对接结构计算了偏心值，并利用力法对附加弯矩在对接区的分布进行了计算分析。以某A型飞机的对接结构为基础，建立了4组插入式下壁板对接结构的模型，每组模型的中央翼下翼面位置相对外翼的不同；分别用力法和有限元法对附加弯矩进行了计算。结果表明：可以通过优化中央翼下翼面外形面的相对位置达到减小对接区附加弯矩的目的。描述了另外两种下壁板对接形式的附加弯矩情况，并和插入式的进行了简单比较。最后，总结了为减小区域附加弯矩及其不利影响在对接结构设计上需要注意的点。

Additional bending moment in lower panel butt-joint of inserted wing

The butt-joint of inserted wing lower panel butt-joint has the advantages of stable twin shear force transfer and good fatigue performance, but its structure center line changes obviously in the butt-joint area, bringing additional bending moments. To minimize the additional bending moments in the docking area, a method is proposed to optimize the position of the lower wing surface of the central wing relative to the lower wing surface of the outer wing when establishing the aircraft skeleton model. Based on the characteristics of butt-joint structure of insertion wing lower panel, the origin of eccentricity of butt-joint structure and the formation of additional bending moment are expounded; the eccentricity value of butt-joint structure of a certain type A aircraft is calculated, and the distribution of additional bending moment in butt-joint area is calculated and analyzed by the force method. Based on the docking structure of a certain type A aircraft, four groups of models of inserting lower panel docking structure are established, and the position of the lower wing of each group is different from that of the outer wing. The results show that the additional bending moment in the docking area can be reduced by optimizing the relative position of the lower wing surface of the central wing. The additional bending moments of the other two butt-joint forms of the lower panel are described and compared with those of the insertion type. Finally, the paper summarizes the caveats in the design of docking structures for the reduction of the additional bending moments and their adverse effects.