关键词: 阻尼车轮, 旋转, 2.5维有限元法, 2.5维声学边界元法, 振动声辐射, 降噪机理

Abstract: Wheel/rail noise is a dominant component of railway noise, and sound radiation from the wheel is one of the main contributors to wheel/rail noise. Therefore, developing low-noise wheels is the key to reduce railway noise. Based on a straight web wheel used on high-speed trains in China, nine damped wheels are generated using 9 different damping layer designs. Vibrations and sound radiations of 10 wheels (9 damped wheels plus 1 standard wheel) subject to the radial wheel/rail force are calculated by using the 2.5-dimensional finite element method (2.5D FEM) and the 2.5-dimensional acoustic boundary element method (2.5D BEM). For comparison, results are produced for the wheels in rotation as well as not in rotation. Results show that the sound power level of a wheel with rotation considered is always higher than that if the rotation is omitted, and the maximum difference is 3.55 dBA for the cases considered. It is found that results predicted without considering wheel rotation may be misleading. The best noise reduction achieved by the constrained layer damped wheels is better than that by the free layer damped wheels. For a given design of constrained layer damped wheel, using steel as the constrained layer is much better than using aluminum. Among the 9 designs, the one with a damping layer of 3 mm thickness and a steel constrained layer of the same thickness pasted on one side of wheel web performs the best, achieving 4.3 dBA in terms of noise reduction; placing the constrained damping layer on the other side of the wheel web does not make much difference. The noise reduction is achieved mainly by suppressing the vibration of the 1-circle number mode of the wheel under unit wheel/rail force, and the effect caused by the change in wheel-rail force is insignificant.

Key words: damped wheel, rotation, 2.5D FEM, 2.5D BEM, vibration and sound radiation, noise reduction mechanism