论文部分内容阅读
铁路无砟轨道区段的噪声辐射比有砟轨道区段严重,常采用轨道表面铺设吸声板来降低轮轨噪声对周边环境的影响。为了控制铁路无砟轨道区段的轮轨噪声辐射,根据微穿孔板吸声理论建立多孔吸声板吸声系数计算模型,并将计算得到的吸声系数输入到轮轨噪声预测系统中,得出轨旁噪声的频谱和等效声级,分析多孔吸声板的空隙率、厚度和孔径对降低轮轨噪声的影响规律。研究结果表明:多孔吸声板的空隙率越大,对轮轨噪声的吸声效果越好,但太大的空隙率会降低对中高频轮轨噪声的吸收,建议空隙率应该控制在0.4%～0.6%之间为宜;多孔吸声板厚度越大,对轮轨噪声的吸声效果越好,但板厚过大会影响到其他行车安全问题,板厚应控制在既能高效降低噪声、又能保证行车安全的限值之内;多孔吸声板的孔径越大,对轮轨噪声吸声效果越差。
The noise radiation of the ballastless track section of the railway is more serious than that of the ballasted track section, and the sound absorbing board is often used to reduce the impact of the wheel-rail noise on the surrounding environment. In order to control the wheel-rail noise radiation of the ballastless track section of railroad, a model for calculating the sound absorption coefficient of porous sound-absorbing panels is established according to the sound absorption theory of micro-perforated plates. The calculated sound absorption coefficient is input into the wheel-rail noise forecasting system Spectrum and equivalent sound level of noise beside derailment, the influence law of porosity, thickness and aperture of porous sound-absorbing board on reducing wheel-rail noise was analyzed. The results show that the larger the porosity of the porous acoustic panel, the better the sound absorption effect of the wheel and rail noise, but the too large porosity will reduce the absorption of the medium and high frequency wheel and rail noise. The proposed porosity should be controlled at 0.4% ~ 0.6%. The larger the thickness of the porous sound-absorbing board, the better the sound-absorbing effect on the wheel-rail noise is. However, if the board thickness is too large, other driving safety problems will be affected. The board thickness should be controlled to not only effectively reduce the noise, But also to ensure traffic safety within the limits; porous sound-absorbing board, the larger the aperture, the worse the sound absorption effect of the wheel and rail noise.