大展弦比复合材料机翼非线性变形及模态分析

Nonlinear deformation and modal analysis of high aspect ratio composite wing

为明确大展弦比复合材料机翼铺层渐变过程中的几何非线性变形及模态分布情况,构建了三种等厚度材质(全金属、半复合材料、全复合材料)机翼的有限元模型,基于CFD/FEM的计算方法研究了不同马赫数及不同攻角下三种机翼的弯曲变形、扭转变形以及模态分布。通过对比分析发现:三种材质机翼的弯曲与扭转变形均会随着马赫数的增加而呈现出非线性增长趋势,而攻角的改变则对机翼结构的非线性变形影响较小;复合材料铺层可以有效提高机翼结构的固有频率,添加45°铺层角度的机翼蒙皮、翼肋乃至翼梁,针对机翼扭转变形突显了较好的力学特性,有利于机翼结构的抗振设计;随着马赫数的增大,机翼各阶模态频率均呈现出下降趋势,其中高阶模态频率相对低阶模态频率下降趋势更加明显。

Aiming to understand the geometrical nonlinear deformation and modal distribution of the high aspect ratio composite wings in the process of layer design, the finite element models of the wings of three kinds of material(metal,part of composite materials, composite materials) are constructed based on CFD/FEM calculation method for solving bending deformation,torsion deformation and modal distribution of three wings with different Mach number and different angle-of-attack. The results show that the bending and torsional deformation of three materials of wings show a nonlinear growth trend with the increase of Mach number, while the change of angle-of-attack has little influence on the nonlinear deformation of the wings. The composite layer can effectively improve the natural frequency of the wing structure, and the addition of 45° layer angle of the wing skin, ribs and even spar highlights the good mechanical properties against the wing torsional deformation, which is beneficial to the vibration design of the wing structure. With the increase of Mach number, all the modal frequencies of the wing show a decreasing trend, and the high order modal frequency has a more obvious decreasing trend than the low order modal frequency.