考虑旋转效应的弹性车轮降噪效果与影响参数研究

以某款弹性车轮及其原型普通车轮为研究对象，在考虑车轮旋转带来的移动荷载效应和陀螺效应的前提下，应用2.5维结构有限元法和2.5维声学边界元法预测车轮在给定轮轨粗糙度激励下的振动和声辐射；针对40、80和120 km·h-1三个运行速度，分析了弹性车轮的降噪机理，研究了弹性车轮橡胶层的材料参数对弹性车轮降噪效果的影响。研究结果表明:车轮旋转使得原本非0节径模态频率处的声功率峰值分叉为2个峰值，其中一个峰值频率比原模态频率高，另一个峰值频率比原模态频率低，2个峰值频率差近似等于车轮的旋转频率乘以2倍的模态节径数；在所考虑的工况下，车轮旋转对车轮声辐射的影响最高达3.2 dB(A)，因此，在预测车轮的声辐射时，必须考虑旋转对预测结果的影响；如果橡胶弹性模量太小，则轮箍容易振动，从而有可能辐射比普通车轮更高的噪声；从车轮声辐射的角度，橡胶弹性模量存在一个最佳值，在这个值下，弹性车轮的声功率最低，且低于原型车轮的声功率10 dB(A)以上；增加橡胶阻尼总是有利于车轮噪声的控制，但增加阻尼产生的降噪效果随橡胶弹性模量的增大而降低；对于同一弹性车轮，随着运行速度的提升，相对原型普通车轮的降噪效果不断降低，速度从40 km·h-1增大到120 km·h-1，降噪效果降低达4 dB(A)以上。 

Study of noise reduction effect and influencing parameters for a resilient wheel considering rotation effect

An resilient wheel and its prototype ordinary wheel were taken as the research objects, the 2.5D structural finite element method and 2.5D acoustic boundary element method were used to predict the vibration and sound radiation of the wheels under the excitation of a given wheel-rail roughness and considering the moving load effect and gyro effect caused by the wheel rotation. The noise reduction mechanism of the resilient wheel was analyzed at the three running speeds of 40, 80 and 120 km·h-1, and the effect of the material parameters of the resilient wheel rubber layer on the noise reduction effect was studied. Research results show that the wheel rotation makes the acoustic power peak at the original non-zero node-diameter mode frequency bifurcated into two peaks, one of which is higher than the original mode frequency, and the other is lower than the original mode frequency. The difference between the two peak frequencies is approximately equal to the wheel rotation frequency multiplied by two times the number of mode node-diameter. Under considering all cases, the effect of the wheel rotation on the sound radiation of the wheel can be as high as 3.2 dB(A). Therefore, the vibro-acoustics of the wheel must be predicted by considering the wheel rotation. If the Young's modulus of the rubber layer is too low, the wheel rim will vibrate so strongly that the wheel radiates higher sound power than the ordinary wheel. In terms of sound radiation, there is an optimal Young's modulus for the rubber layer, at which the resilient wheel radiates lowest sound power more than 10 dB(A) lower than the ordinary wheel. Increasing rubber damping will reduce the sound radiation from the wheel, however, the reduction is adversely affected by the Young's modulus of the rubber. With the increase of running speed, the noise reduction effect of resilient wheel decreases continuously compared with the prototype common wheel, and the reduction is more than 4 dB(A) when wheel speed increases from 40 km·h-1 to 120 km·h-1. 4 tabs, 10 figs, 27 refs.