大展弦比机翼非线性颤振剪裁设计新方法

A NEW METHOD ON FLUTTER TAILORING TECHNIQUES OF HIGH-ASPECT-RATIO WINGS

针对大展弦比机翼水平弯曲模态参与耦合颤振问题,首先用考虑几何非线性的颤振分析方法研究了某大展弦比机翼的颤振特性,结果表明水平一弯模态参与耦合降低了机翼传统模式的线性颤振速度;然后研究了复合材料的铺层主刚度方向角对机翼非线性振动特性和颤振特性的影响规律,提出了大展弦比机翼非线性颤振剪裁设计的新方法.结果表明主刚度方向角的变化主要引起了水平一弯模态振型的改变,一般表现为主刚度方向角从机翼后梁向后缘偏转,该阶模态的相对扭转振型节线位置向前缘移动;反之,该节线位置后移.进一步非线性颤振分析,发现水平一弯模态振型的变化引起了该阶模态参与耦合颤振速度的明显改变,主要表现为该颤振型的颤振速度随该阶模态的相对扭转振型节线位置前移量的增加而增大.通过两个算例验证了结论的正确性.

A method was presented to analyze the nonlinear flutter. Based on this method,the flutter characteristics of the high aspect wing were illustrated. The numerical results show that the flutter speed is decreased when the first horizontal bending mode involved. Secondly,this study discussed how the main direction of the composite influenced the character of the nonlinear vibration and flutter,and established the method of the flutter clipping to the high aspect wing. And the result shows that the stiffness of structure can be changed by changing the main direction of the composite. It mainly changes the horizontal bending mode,makes the main direction tend to the trailing edge,and then makes the section line move to the leading edge. Further analyzing the nonlinear flutter reveals that it is the changing of the horizontal bending mode that causes the flutter speed change obviously.And by the section line of this mode moves ahead,the flutter speed will become larger. In the study,two examples were illustrated to validate its truthiness.