高铁板式轨道区段箱梁结构噪声辐射分析

Noise Radiation Analysis of Box-girder Structure in Slab Track Section of High Speed Railways

利用Simpack软件建立高速列车-轨道耦合动力学模型,计算在轨道不平顺谱激励下的轮轨垂向力,以此作为载荷边界条件施加到高架箱梁结构的有限元模型。计算了高架箱梁表面的振动响应,并利用箱梁结构振动响应作为声学边界条件。进而又采用间接边界元法对其进行声辐射分析。研究结果表明,利用板壳单元,采用有限元—边界元方法能够有效计算混凝土简支箱梁结构的振动噪声,主要集中在0~200Hz的低频段,峰值主要出现在中心频率16Hz、25Hz与80 Hz^100Hz;横向声场的声压级随着距离的增加而减小,频率越低越明显;垂向声场的声压级整体上随离地面距离的增加而增大,其中远场区域的声压级在低于31.5Hz的频段内变化不大,在80 Hz^100Hz频段内箱梁结构对其附近及上方区域的结构噪声大于其它区域,尤其是箱梁正上方。

A high speed train-track coupling dynamics model was established using Simpack software, and the wheel/rail vertical contact force excited by track irregularity spectrum was calculated. The wheel/rail vertical force was taken as aboundary condition and applied to the finite element model （FEM） of an elevated box girder structure to calculate its surfacevibration response. Then, the vibration response was taken as the acoustic boundary conditions and was applied to the boundaryelement model （BEM） of the elevated box-girder structure to analyze its sound radiation. The results show that, using thefinite element method and the boundary element method, the vibration noise of the concrete simply- supported box-beamstructure can be effectively calculated with shell elements. The vibration noise is mainly concentrated in the low frequencyrange of 0-200 Hz, and the peaks mainly appear at the central frequencies of 16 Hz, 25 Hz, 80 Hz-100 Hz. The sound pressurelevel decreases with the increase of the distance from the ground in the lateral sound field and this tendency is more obviousfor lower frequency sound field. The sound pressure level generally increases with the increase of the distance fromthe ground in the vertical acoustic field, and the sound pressure level in far field area does not change obviously for the frequenciesbelow 31.5 Hz. In the range of 80 Hz-100 Hz, the sound pressure levels of the field points near the girder, especiallyabove the girder, are higher than those in the other regions.