弹性边界对高速列车车窗声辐射特性的影响研究

Research on Elastic Boundary Supports on Sound Radiation of High-speed Train Windows

为研究高速列车车窗在点激励下的声辐射特性,基于Hamilton原理和声学Rayleigh积分建立了弹性边界条件下车窗的有限元-边界元耦合模型,模型中将弹性边界简化为沿车窗四周连续分布的平动弹簧和转动弹簧。利用矩形板在经典边界条件下的模态分析结果、无限大板的声辐射验证了模型的正确性。基于验证后的模型,分析了边界支撑刚度对车窗声辐射的影响,研究了车窗声辐射随边界阻尼的变化规律。研究结果表明,边界平动刚度对车窗声辐射的影响较转动刚度显著;当平动刚度小于1×10^(3)N/m时,车窗的声辐射与无限大板的结果相似;当平动刚度在1×10^(3)~1×10^(6)N/m间变化时,声辐射出现明显峰值,且随刚度迅速变化,这些峰值由车窗的模态引起;当平动刚度大于1×10^(6)N/m时,车窗的声辐射随刚度趋于稳定;提高边界阻尼有助于降低车窗在辐射峰值附近的声辐射水平,但作用有限,其中,由复平动刚度产生的边界阻尼比复转动刚度产生的边界阻尼对车窗声辐射的影响大。

In order to study the sound radiation(SR)of the high-speed train windows,a coupling finite element and boundary element(FE-BE)model of the window subject to elastic boundary supports is established based on the Hamilton principal and the Rayleigh integral.In the model,the elastic boundary supports are simulated as translation and rotation springs continuously distributed along the periphery of the window.The FE-BE model is verified by comparing the results with the modal analysis of a rectangular plate subject to classical boundary conditions and the SR of an infinite plate.Using the FE-BE model,the effect of boundary spring stiffness on the SR of the window is analyzed and the influence of the damping arising from the boundary springs is investigated.The results show that the stiffness of the translation springs has a more significant influence on the SR than that of the rotation springs;when the stiffness of the translation springs is less than 1×10^(3)N/m,the SR of the window is similar to that of an infinite plate;when the stiffness ranges from 1×10^(3)to 1×10^(6)N/m,several significant SR peaks caused by the modes of the window emerges and varies rapidly with the stiffness increasing;when the stiffness is even larger,the SR tends to be stable;increasing the boundary damping is helpful to suppress the SR near the peaks,while the impacts are limited;the damping arising from the translation springs has greater effect on the SR of the windows than that from the rotation springs.