基于能量流的约束阻尼层对铁路结合梁桥振动与噪声的控制机理研究

The vibration and the noise induced by running trains from railway composite bridges with low stiffness and light damping are two of the most prominent issues. Constrained layer damping is effective to suppress the vibration and noise from thin-walled structures in wide frequency range, while the mechanism and laws of applying constrained layer damping to reduce the bridge’s vibration and noise have not been well perceived in the current study. Based on the energy flow method this project is going to establish a theoretical model to compute the vibration and the noise from railway bridges with constrained layer damping in the frequency domain, combining train-track-bridge coupled vibration, modal strain energy and statistical energy analysis. Then a scale test of vibration and noise from several steel girders with constrained layer damping in the semi-anechoic chamber is conducted to verify the theoretical model. The laws of constrained layer damping on the bridge’s mobility and acoustic radiation efficiency are investigated. The characteristics of the vibration energy dissipation in the vibration transmission path of the bridge equipped with constrained layer damping are explored. The mechanisms on the constrained layer damping reducing spatial vibration and noise in different frequency bands are revealed. The qualitative and quantitative relationship between the material and geometric parameters of constrained layer damping with the actual bridge structure is proposed. The research achievements of this project are able to provide a theoretical analyzing method and scientific references for constrained layer damping applying to suppress the vibration and noise from railway bridges.

铁路结合梁桥因自身刚度和阻尼较小，导致列车经过时的桥梁振动与噪声问题十分突出。约束阻尼层适合薄壁结构在较宽频率范围内的振动与噪声控制，而当前对约束阻尼层用于桥梁减振降噪的机理和规律认识不足。本课题拟从能量的角度，基于车-线-桥耦合振动功率流方法、模态应变能法和统计能量分析，在频域建立约束阻尼层铁路桥梁车致振动与噪声的理论分析模型，并由半消声室内的约束阻尼层钢梁振动与噪声试验进行验证。探讨约束阻尼层对桥梁导纳和声辐射效率的影响规律；研究约束阻尼层在振动传递路径中的耗能减振特点；揭示约束阻尼层在空间和频域的减振降噪机理；提出约束阻尼层的材料和几何参数与实际桥梁结构之间的定性和定量匹配关系。本课题研究成果可为约束阻尼层用于铁路桥梁的振动与噪声控制提供理论分析方法和科学依据。

铁路结合梁桥因自身刚度和阻尼较小，导致列车经过时的桥梁振动与噪声问题十分突出。约束阻尼层适合薄壁结构在较宽频率范围内的振动与噪声控制，而当前对约束阻尼层用于桥梁减振降噪的机理和规律认识不足。本项目从能量的角度，基于车-线-桥耦合振动功率流方法、模态应变能法和统计能量分析，在频域建立敷设约束阻尼层的铁路结合梁桥车致振动与噪声理论分析模型，并由钢梁约束阻尼层减振降噪模型试验和实际铁路结合梁桥振动与噪声现场试验进行验证；比较了铁路结合梁桥主要构件辐射噪声的差异，揭示了结合梁桥车致振动与噪声的频谱特性和传播规律；发展了考虑黏弹性阻尼材料剪切模量和损耗因子频变特性的约束阻尼层子系统的内损耗因子确定方法；揭示了约束阻尼层对铁路桥梁的减振降噪特性和机理；开展了约束阻尼层用于桥梁减振降噪的参数灵敏度分析，探讨了阻尼层剪切模量、约束层弹性模量和阻尼层厚度、约束层厚度等参数对铁路桥梁减振降噪的影响规律，提出了与实际桥梁结构相匹配的约束阻尼层设计参数。本项目提出的约束阻尼层装置应用于秦沈客专钢-混结合梁桥，成功降低桥梁振动和噪声超过3dB。另外，本项目建立的理论分析模型在广州地铁高架桥的噪声预测和减振降噪设计中也得到成功应用。项目研究成果获教育部科技进步二等奖和中国铁道学会科技进步二等奖各1项。