基于气动力分段表达的颤振求解方法与模态跟踪技术的应用

Flutter analysis based on the piecewise express of aerodynamic forces and the application of mode tracking technology

  • 摘要: 在频域颤振方程的求解中,PQI法采用分段气动力的表达形式将颤振方程进行分段直接求解,避免了迭代。由于广义气动力分段插值函数PQI的构建依赖折合频率的选取,将构造的分段插值函数嵌入颤振方程中求解存在模态窜支问题,对此发展了一种基于特征值摄动理论的预测跟踪法来确定各阶模态对应的特征值随参数变化的前后对应关系。文中介绍了PQI颤振分析的基本方法,并采用P-K法进行对比分析来验证算法的计算精度,最后将发展方法应用到某飞机全机轴对称状态颤振分析中来验证算法在实际工程颤振分析中的有效性,数值结果表明该方法计算精度高,模态跟踪效果良好。

     

    Abstract: During solving the frequency domain flutter equations via the piecewise quadratic interpolation(PQI) method, this method can directly calculate the aerodynamic forces by using the piecewise aerodynamic force expression form. Thus, this method avoids the iteration process. Because of the construction of the function of the generalized aerodynamic forces depends on the choice of the reduced frequencies, a sudden jump of structural modes may occur when the PQI method is used in the flutter analysis. For this reason, a predictor-corrector scheme based on the perturbation theory of eigenvalues is developed. The scheme can determine the correspondence between the baseline and perturbed eigenvalues with parameter variation. In this paper, the present scheme is used in the flutter analysis. As an illustrative example, the developed method is applied to the whole plane flutter analysis with the axisymmetric boundary condition. By comparing with the P-K method, the numerical results show that the PQI method can accurately predict the flutter boundary and the mode tracking scheme is effective.

     

/

返回文章
返回