充气式机翼的颤振特性分析

摘要

充气式机翼的结构刚度由内充气压决定,其颤振特性需要建立静、动力学耦合的分析方法.机翼结构刚度和固有振动特性需要在静力分析基础上计算,进一步计算非定常气动力,从而采用传统的颤振计算方法分析其颤振特性.针对某一充气式机翼采用膜单元建立了有限元模型.在不同内充压条件下,对充气机翼进行了静力分析得到其结构刚度;然后对机翼进行模态计算和颤振分析.研究表明：各阶模态的频率随内充气压的升高而升高;除典型的弯扭模态外,充气机翼的弦向弯曲模态频率较低;充气机翼的颤振形式除常规的弯扭模态耦合外,弦向弯曲模态同样会发生颤振;机翼的临界颤振速度随内充压的变化近似呈分段线性变化;临界颤振模态及耦合分支在一定气压范围内保持不变.%The stiffness of inflatable wing is determined by the internal pressure,so the static and dynamic coupling method should be established to solve the flutter problems of such wings.The structural stiffness and the normal modes should be calculated on the base of the static analysis.Then the unsteady aerodynamics can be calculated and the flutter characteristics of the wing can be analyzed using the traditional methods.For an inflated wing,the finite element model was created using membrane elements.The structure stiffness of the wing was derived by the static analysis and the normal modes were calculated.Then the flutter of the wing was analyzed.The results show that,as the internal pressure increases,each mode＇s natural frequencies increases.Except for the typical bending and torsion modes,the chord-wise bending modes have low frequencies.The chord-warping modes can induce flutter besides the conventional bending-torsion flutter type.The critical flutter speed of the inflatable wing presents nearly linearity with internal pressure increased in specific range and the corresponding flutter modes dose not change as well.