曲线纤维复合材料后掠机翼的颤振特性优化

Aeroelastic Tailoring of the Swept-back Wing made of Composite Laminates with Curvilinear Fiber

曲线纤维铺层是制造变刚度复合材料层合板的一种新技术,本文以12层曲线纤维复合材料后掠机翼为研究对象,研究了不可压缩流动中后掠机翼的颤振特性优化,分析了纤维方向、优化层数和铺层厚度对颤振特性的影响。数值仿真中分别采用有限元法和高阶面元法建立后掠机翼的结构模型和气动力模型,利用VG法求解后掠机翼的颤振边界。计算结果表明,后掠机翼全部铺层采用曲线纤维时优化后颤振速度,比仅最外层采用时提高31.1%,比全部铺层采用直线纤维时优化后颤振速度提高14.3%。铺层全部采用二维方向可变曲线纤维时的颤振速度比一维角度可变的颤振速度仅提高1.7%,证明纤维方向沿展向可变对颤振边界影响更大。纤维方向和厚度共同优化时,在不改变后掠机翼总厚度的情况下可使后掠机翼的颤振速度再次提高5.4%。研究表明,采用曲线纤维进一步提高了复合材料层合板的可设计性,通过调整曲线纤维路径可以明显改变复合材料后掠机翼的颤振特性。

The manufacture for laminates with curvilinear fibers is a new technology for manufacturing composite laminates with variable stiffness.In this paper,the swept-back wing of 12-layer composite laminates with curvilinear fiber is studied.Aeroelastic tailoring of the swept-back wings in incompressible flow and the effects of fiber angle,optimal layer numbers and layer thickness on flutter characteristics are analyzed.In the numerical simulations,the structural model and aerodynamic model of the swept-back wing are established by finite element method and higher order panel method,respectively.The flutter boundary of the swept-back wing is computed via VG method.The results show that the flutter speed of the swept-back wing made of all laminates with curvilinear fiber is 31.1%higher than that made of only the outer layer with curvilinear fiber,and 14.3%higher than that made of laminates with linear fiber.The flutter velocity with two-dimensional fiber angle variations used is only 1.7%higher than that with one dimensional fiber angle variations used,which proves that the variable fiber direction along the span-wise direction has a greater influence on the flutter boundary.When fiber angles and thickness are optimized together,the flutter velocity of the swept-back wing can be increased by 5.4%without changing its overall thickness.The results show that the design ability of the aeroelastic tailoring can be further improved via using composite laminates with curvilinear fibers.The flutter characteristics of the composite swept-back wing can be significantly changed by adjusting the path of curvilinear fibers.