基于波导有限元和模态理论的铁路混凝土箱梁声辐射机理研究

项目名称： 基于波导有限元和模态理论的铁路混凝土箱梁声辐射机理研究

项目编号： No.51308469

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 建筑科学

项目作者： 张迅

作者单位： 西南交通大学

项目金额： 25万元

中文摘要： 混凝土箱梁在轮轨不平顺激励下发生振动并辐射噪声，该噪声由于频率较低易引起人们烦扰、不适，是一种难以控制的噪声源。本课题基于波导有限元和模态理论，采用理论分析、数值模拟和现场试验相结合的方法，从外界能量输入和箱梁固有振动声辐射特性两个层次探索箱梁的声辐射机理。基于前期建立的混合有限元/边界元模型，分析箱梁结构噪声的频谱特性和优势频率范围，建立噪声频谱特性与各影响因素的内在联系，作为后续研究的出发点；基于波导有限元法，在频域内建立车-线-桥耦合系统振动功率流模型，揭示箱梁振动功率流的传递机制；基于局部振动模态和多极子理论，揭示箱梁振动模态声辐射效率、声辐射指向性的规律；基于空腔声模态理论，探讨箱内"空腔共鸣"现象的发生机理及其解决措施；基于声辐射模态理论，建立振动模态和声辐射模态之间的桥梁，揭示箱梁减振、降噪的双重机理。本项目研究成果可为箱梁减振、降噪理论及工程应用提供科学的理论依据。

中文关键词： 混凝土箱梁；振动；噪声；振动功率流；模态理论

英文摘要： Wheel-track irregularity excitation causes vibration of concrete box-girder bridge, which then radiate noise. The low-frequency characteristic of it arouses annoyance, uneasiness, and thus become an insolvable problem. Based on the waveguide finite element and modal theory, this project combines theoretical analysis, numerical simulation and field test to explore the sound radiation mechanism of box-girder bridge from two levels of energy input and its intrinsic vibration-sound radiation characteristics. Based on pre-established hybrid FEM/BEM model, the spectral characteristics and dominant frequencies of box-girder bridges are analyzed to establish the internal relations of them with various influencing factors, and as a starting point for future research. Then, the waveguide finite element method (WFEM)is adopted to establish the vibration power flow model of train-track-bridge coupling system in frequency-domain, and the mechanism of vibration power flow of box-girder bridge is reveled. From the local vibration mode and multipole theory, the laws of vibration mode acoustic radiation efficiency and acoustic radiation directivity are determined. After that, the mechanism of cavity resonance phenomenon and its countermeasures are studied based on cavity acoustic mode of box-girder bridge. At last, based on acou

英文关键词： concrete box-girder bridge；vibration；noise；vibration power flow；modal theory