轨道车辆车轮辐板阻尼层对其降噪效果的影响分析*

采用模态叠加法求得阻尼车轮导纳特性,利用已建立的轮轨滚动噪声预测模型,以轮轨表面粗糙度为激励,分析了辐板阻尼层与其厚度对阻尼车轮振动与声辐射特性的影响规律.首先,建立了阻尼车轮三维实体有限元模型,采用Block Lanczos方法计算车轮模态特征;其次,利用模态叠加法求得车轮在单位荷载激励下的频响函数;然后,利用虚拟激励法求得车轮在粗糙度谱激励下的频域振动特性;最后,依据车轮动态响应通过解析的方法求得车轮声辐射频域特性.计算结果表明:(1)车轮辐板敷设阻尼层对车轮1000Hz以下频率的振动与噪声的抑制作用不明显,而对车轮1600Hz以上的高频振动具有良好的抑制作用;(2)车轮辐板双侧敷设阻尼的降噪效果优于单侧阻尼;(3)阻尼层可以有效抑制车轮振动,且车轮辐板敷设阻尼层厚度越厚效果越明显.

EFFECT OF WEB DAMPING LAYER ON NOISE REDUCTIONOF RAIL VEHICLE WHEEL*

The modal superposition method was used to obtain the admittance characteristics of damped wheels. Based on the established prediction model of wheel/rail rolling noise and taking the surface roughness of wheels and rails as the excitation, the influence of the position and thickness of a damping layer on vibration and sound radiation characteristics of damped wheels was analyzed. Firstly, a three-dimensional solid finite element model of damped wheels was established, and the Block Lanczos method was used to calculate the modal characteristics of wheels. Secondly, the frequency response function of wheels under unit load was obtained by the modal superposition method. Then, the frequency domain vibration characteristics of wheels under the excitation of roughness spectrum were obtained by the virtual excitation method. Finally, the frequency domain characteristics of acoustic radiation were obtained by an analytic method based on the dynamic responses. The results showed that the damping layer laid on the wheel web has no obvious effect on vibration and noise suppressions of the wheel below 1000Hz, but performs good function above 1600Hz. The noise reduction by the damping layer laid on both sides of the web of the wheel is better than that by the damping layer only laid on one side. The thicker the thickness of the damping layer is, the more obvious the noise reduction is.