悬臂方薄板振动的辐射声场及竖裂纹对其频谱的影响

在将悬臂板挠度表示为正交多项式之和的基础上，利用瑞利-里兹方法求解了悬臂板的前几阶振动模态频率及挠度．进而利用瑞利积分求解了其自由振动辐射声场的分布规律。用分区技术的瑞利-里兹方法求解了竖裂纹对悬臂板低阶模态频率的影响，并将计算结果与有限元结果作了对照。实验上用小球撞击法测定了含竖裂纹悬臂板辐射声场的频谱，谱成分与有限元结果基本符合。

The sound field of a vibrating cantilever rectangular plate and effect of a perpendicular crack on its spectra

Based on the result that the deflection of a rectangular plate is expressible as the summation of orthogonal polynomials, the frequencies and deflections of the low modes of a cantilever rectangular plate are determined by the Rayleigh-Ritz method and then using Rayleigh integration the distribution of the sound field radiated by the freely vibrational plate is presented. The Rayleigh-Ritz method with a sub-sectioning technique is used to obtain the low mode frequencies of the cantilever rectangular plate with a perpendicular crack, and the results are compared with the FEM results. Experimentally the spectra of the sound field are measured using collision-exciting method, and the frequencies are in agreement with FEM results.