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针对导弹在延寿试验过程中振动谱设计精度低、与实际载荷剖面差距大的问题,提出一种基于逆虚拟激励法的导弹振动谱设计方法。首先,建立了导弹-悬架系统四自由度振动模型,推导出系统激励响应关系;然后,对系统时域响应数据进行Fourier变换,得到响应功率谱矩阵并对其进行分解,构造虚拟简谐响应;最后,基于逆虚拟激励法求得系统激励功率谱,并讨论了响应噪声及系统阻尼对识别精度的影响。实验结果表明:本文方法对于随机振动载荷的识别精度较高、鲁棒性好,零噪声识别误差为2.39%,30%噪声条件下识别误差为3.21%。本文方法同样适用于其他装备的振动试验谱的设计。
Aiming at the problem of low precision of vibration spectrum and large gap between actual vibration and load profile during the life prolongation test, a missile vibration spectrum design method based on inverse virtual excitation is proposed. Firstly, the vibration model of four degrees of freedom of the missile-suspension system was established and the system excitation response was deduced. Then, the time-domain response data of the system was Fourier transformed to obtain the response power spectrum matrix and decompose it. The virtual harmonic response Finally, the excitation power spectrum of the system is obtained based on the inverse virtual excitation method, and the influence of response noise and system damping on the recognition accuracy is discussed. The experimental results show that the proposed method has high recognition accuracy for random vibration loads and good robustness. The recognition error of zero noise is 2.39% and the recognition error is 3.21% under 30% noise. The method of this paper is also applicable to the design of vibration test spectrum of other equipment.