高架轨道典型结构内损耗因子实验及验证

Experiment and Verification of Internal Loss Factors of Elevated Track Typical Structures

内损耗因子是衡量结构阻尼特性并决定振动能量耗散能力的重要参数,对高架轨道结构噪声的分析具有重要影响。基于瞬态衰减法基本原理,采用Hilbert法对高架轨道典型薄板结构进行测试分析,通过获取信号的衰减包络线,可求得结构在各频段的平均内损耗因子。基于测试所得损耗因子,建立混合FE-SEA箱梁模型,计算出箱梁结构噪声,并与实验室测试结果进行比较,最后进行损耗因子参数分析。结果表明:薄板结构的损耗因子大致范围在0.01~0.02;高架轨道结构辐射声压级大小随着内损耗因子增大,呈现出衰减的规律;箱梁结构噪声的测试值与仿真结果一致性较好,测试方法可行并可为高架轨道结构损耗因子测试提供参考。

The internal loss factor is an important parameter to measure the damping characteristics of the structures and determine the vibration energy dissipation ability,which has an important influence on the analysis of the noise of the elevated track structures.Based on the basic principle of the transient attenuation method,the typical thin plate structure of the elevated track is tested using Hilbert method.By using the attenuation envelope of the signal,the average internal loss factor of the structure in each frequency band can be obtained.Based on the loss factor obtained from the test,a hybrid FE-SEA box beam model is established,and the structure-borne noise of the box beam is calculated and compared with laboratory test results.Finally,its internal loss factor is analyzed.The results show that the measured value of the box beam structureborne noise is in good agreement with the simulation result;the loss factor of the thin plate structure is roughly in the range of 0.01-0.02;and the radiation sound pressure level increases with the increasing of the loss factor.The feasibility of the test method is verified.This study provides a reference for the loss factor test of the elevated track structures.