阻尼结构叶片强迫振动响应分析的改进时频域融合算法

An improved alternating frequency/time domain method for damped blade forced vibration analysis

为有效地分析阻尼结构叶片系统的动力学特性,对计算非线性动力学系统响应的时频域融合算法进行了改进。引入快速抗混迭傅里叶变换,提高时域与频域间转换运算的精度,减少计算时间。对阻尼结构叶片系统的局部非线性特点,对线性自由度进行减缩,将迭代求解控制在仅和非线性相关的自由度范围之内。采用混合遗传算法改善计算收敛性。使用改进的时频域融合算法对某真实燃机叶片的非线性强迫振动响应进行了分析。在一定的参数条件下,改进的时频域融合算法计算时间为原算法计算时间的26%,且误差不超过1%。研究表明:改进的时频域融合算法能够适用于复杂摩擦接触下阻尼结构叶片的振动响应计算。

To effectively analyze the dynamic characteristics of a damped blade system, an improved alternating frequency/time domain method was presented. The anti-aliasing fast Fourier transformation was used to improve analysis accuracy and decrease computation time. Because of local nonlinearity in a damped blade system, the receptance method was employed to condense linear DOFs so that the iterative procedure of solution was limited in nonlinear DOFs. A hybrid genetic algorithm was taken to get better convergence. The proposed method was used to calculate the nonlinear forced response of a real gas turbine blade. The calculation time of the improved method was 26 percent of the original one, while the results difference between the two methods was about 1 percent. The results indicated the applicability of the proposed method for dynamic analysis of a damped blade system with complex dry friction.