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减小内燃机缸体振动,将减小由缸体本身、油底壳和安装在它上面的其它部件的辐射噪声。实验模态分析是预测缸体结构振动和辐射噪声的有效手段。由测量数据估计频响函数是缸体结构实验模态分析的前期步骤,最终的预测结果在很大程度上依赖于频响函数的估计精度。本文提出使用谱均衡瞬态随机激励方法,以改善结构频响函数的估计精度。文中给出的内燃机缸体试验结果表明,使用这种激励可以得到这类结构频响函数的最佳线性估计。
Reducing the vibration of the cylinder of the internal combustion engine will reduce the radiated noise from the cylinder itself, the oil pan and other components mounted thereon. Experimental modal analysis is an effective method to predict the vibration and radiation noise of cylinder structure. The frequency response function estimated from the measurement data is the first step in the experimental modal analysis of the cylinder structure. The final prediction result largely depends on the estimation accuracy of the frequency response function. In this paper, the spectral equalization transient random excitation method is proposed to improve the estimation accuracy of structure frequency response function. The experimental results of cylinder block given in this paper show that the optimal linear estimation of the frequency response function of such structures can be obtained by using this kind of excitation.