混凝土箱梁相似模型结构噪声对比分析*

为探讨混凝土箱梁噪声的时变特性,以京沪高铁32 m混凝土简支箱梁为原型,制作了1:10的缩尺模型,通过模态试验的方法验证箱梁模型与原型的相似关系,通过声学试验验证箱梁声学计算模型的正确性。然后,建立了箱梁缩尺模型与原型两种计算模型,利用有限元和边界元法求出两种模型的瞬态结构噪声。研究发现,箱梁缩尺模型与箱梁原型的材料参数满足一定关系,模型试验的方法能够验证箱梁模型与箱梁原型之间符合相似关系,箱梁模型的振动噪声测试结果能真实反映原型振动噪声水平。两种模型的结构噪声在时域内声压级及对应场点的声压存在一定相似关系。该研究可为箱梁缩尺模型结构噪声反演至箱梁原型提供依据,所采用的方法和得到的结果对桥梁结构振动与声辐射实验研究具有参考作用。

Comparative analysis on structural noise of similarity model of concrete box girder

To explore the time-varying characteristics of low-frequency noise of concrete box girder, a scale model (1/10) was made by taking 32m concrete simple box-girder of Beijing-Shanghai High Speed Railway, the similarity between the box girder model and the prototype is verified by the modal test method, the acoustic test was used to verify the correctness of the acoustic model of the box girder. Then, two calculation models of box girder scale model and prototype are established, and the transient structure noise of the two models is obtained by using finite element method and boundary element method. It is found that the box girder scale model and the material parameters of the box girder prototype satisfy a certain relationship, the model test method can verify the similar relationship between the box girder model and the box girder prototype, the vibration and noise test results of the box girder model can truly reflect the prototype vibration noise level. The structural noise of the two models has a similar relationship between the sound pressure level in the time domain and the sound pressure of the corresponding field. This research can provide a basis for the inversion of box girder model structure noise to the box girder prototype, the method and results obtained have a reference for the experimental study of bridge structure vibration and acoustic radiation.