简支箱梁振动噪声影响参数研究

为了研究简支箱梁结构噪声,以32 m简支箱梁为研究对象进行车桥耦合动力分析,求解轨道不平顺作用下的竖向轮轨力。以竖向轮轨力作为激励加载在简支箱梁的声场分析模型中,以简支箱梁的动力响应结果作为边界条件,利用边界元和有限元相结合的方法求解声场内声压级的频率分布特性和传播规律。主要研究了行车速度和板件厚度等因素对简支箱梁结构噪声的影响。研究表明,桥梁结构噪声的频段主要在100 Hz以下,顶板上方的噪声声压级最大;结构噪声在传播过程中存在明显的衰减特性,噪声声压级随传播距离增大而减小;车辆运行速度越大,结构噪声声压越大;箱梁刚度和顶板厚度越大噪声声压级越小;相同列车荷载作用下,单箱双室箱梁辐射出的结构噪声声压级比单箱单室箱梁更小。

Study on Influence Parameters of Vibration and Noise of Simply Supported Box Girder

In order to study the structural noise of simply supported box girder, a 32 m simply supported box girder was taken as the research object to carry out a vehicle-bridge coupling dynamic analysis to figure out the vertical wheel-rail force under the effect of track irregularity. In the sound field analysis model of the simply supported box girder with the vertical wheel-rail force as the excitation, frequency distribution characteristics and propagation laws of the sound pressure were analyzed by the method of combining boundary element and finite element with the dynamic response result of the simply supported box girder as the boundary condition.The influence of traveling speed and plate thickness on the structural noise of simply supported box girder was mainly studied. Studies show that the frequency band of bridge structure noise is mainly below 100 Hz, and the noise sound pressure level above the roof is the largest; structure noise has obvious attenuation characteristics during the propagation process, and the noise sound pressure level decreases with the increase of the propagation distance; the higher the vehicle operating speed is, the greater the structural noise sound pressure is; the greater the box girder stiffness and roof thickness are, the lower the noise sound pressure level is;under the same load, the structural noise sound pressure level radiated by the single-box double-chamber box girder is lower than that of the single-box single-chamber box girder.