基于STFT-AOK的星箭力学环境等效频谱分析

Equivalent frequency spectral analysis of mechanical environment for satellite and launch vehicle based on STFT-AOK

星箭力学环境的频谱特性研究对于力学试验环境条件设计非常重要。工程上通常基于冲击响应谱变换获得力学环境参数等效频谱,然而该方法受稳态放大系数Q取值的影响较大。为此,文章提出一种基于短时傅里叶变换–自适应优化核函数(STFT-AOK)融合技术的星箭力学环境等效频谱分析方法。研究结果表明:STFT-AOK方法可在AOK准确定位频率成分和瞬态特征时频区域的基础上,结合STFT的准确幅值,构造出频率分辨率高且幅值准确的时频分布,实现力学环境等效频谱的有效获取,适用于各种复杂瞬态星箭力学环境参数的频谱分析。

The research on equivalent frequency spectra of mechanical environment for satellite and launch vehicle is critical to the design of mechanical test conditions.In engineering practice,the equivalent frequency spectra of mechanical environmental parameters are usually obtained with the help of shock response spectrum transformation.However,this method has limitations that the equivalent frequency spectra change significantly with the steady-state amplification fator Q values.Therefore,a method for equivalent frequency spectral analysis of mechanical environment for satellite and launch vehicle based on short-time Fourier transform-adaptive optimal kernel(STFT-AOK)was presented.It is shown that STFT-AOK method can accurately locate the frequency and the time-frequency region of transient characteristics.In addition,combined with the accurate amplitude of STFT,the time-frequency distribution with high-resolution frequency and accurate amplitude was constructed to effictively obtain the frequency spectra of mechanical environment.The proposed research can be extended to the frequency spectral analysis of various complex transient mechanical environmental parameters for satellite and launch vehicle.