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该文用模态叠加法对城市轨道交通槽型梁进行车-轨-桥耦合动力计算,借助SYSNOISE求出模态声传递向量MATVs,进而用MATVs和梁的模态坐标响应计算桥梁的结构噪声。噪声计算值与实测值在频率分布和幅值上有较高的一致性,证明振动与噪声数值模型的可靠性。槽型梁结构噪声的线性声压级峰值频率为40Hz~80Hz,数值计算表明:动力分析只需考虑轮轨竖向接触即可满足结构噪声计算要求;考虑200Hz以下的声源激励和100Hz以下的结构模态作为边界条件可达到较好的噪声计算精度;调节轨下胶垫的刚度能有效减小结构振动,降低结构噪声2dB~3dB;声压级和车速有强线性关系。
In this paper, modal superposition method is used to calculate vehicle-rail-bridge coupling dynamics of urban rail transit trough girder, and modal acoustic transfer vectors (MATVs) are obtained by means of SYSNOISE. Then the structural noise of bridges is calculated by using the modal coordinate responses of MATVs and girders . The calculated and measured noise have high consistency in frequency distribution and amplitude, which proves the reliability of the numerical model of vibration and noise. The peak frequency of the linear sound pressure level of the trough structure noise is 40Hz ~ 80Hz. The numerical calculation shows that the dynamic analysis only needs to consider the vertical contact of the wheel and rail to meet the calculation requirements of structure noise. Considering the excitation below 200Hz and the excitation below 100Hz Structural modal as a boundary condition can achieve good noise calculation accuracy. Adjusting the stiffness of the rubber under the rail can effectively reduce the structural vibration and reduce the structural noise by 2dB ~ 3dB. The sound pressure level has a strong linear relationship with the vehicle speed.