抗混叠时频域融合算法及在叶片响应分析中的应用

为解决现有的时频域融合算法中反复使用快速傅里叶变换而出现频谱混叠误差和频谱系数周期性重复的问题,采用快速抗混叠傅里叶变换取代原有的快速傅里叶变换,从计算精度和效率两个方面对时频域融合算法进行改进.使用改进后的抗混叠时频域融合算法对某真实叶片的非线性强迫振动响应进行了计算,并与原算法的计算结果进行了比较.计算结果表明:抗混叠时频域融合算法在保证精度的前提下,计算速度约为原算法的4倍.该算法适合于有限元模型、精度要求高的非线性系统的动力学响应分析.

Anti-aliasing alternating frequency/time domain method and its application in response analysis of blade systems

In order to solve the problems of spectrum alias error and spectrum coefficient periodically reiteration cause by using fast Fourier transform(FFT),the fast anti-aliasing Fourier transform was employed to improve analysis accuracy and efficiency of alternating frequency/time domain method.The nonlinear forced response of a real turbine blade was calculated by using the anti-aliasing alternating frequency/time domain method,and the computational accuracy and time were compared with these of the normal method.The results indicate that under certain parameter conditions,the calculation speed of the anti-aliasing alternating frequency/time domain method is about 4 times of the normal one,while the precisions are almost the same.These findings confirm the practicability of the anti-aliasing alternating frequency/time domain method in computing dynamic response of nonlinear systems based on finite element model for high precision analysis.