基于约束阻尼层进行钢梁减振降噪

o study the vibration and noise control effect of constrained layer damping (CLD) for railway bridges, a laboratory test was conducted based on a fabricated steel I-beam. In this test, two types of loading was used, i.e. rigid ball impact and hammer loading. Based on the test data, the modal damping ratio of the I-beam with CLD is larger than that of the bare one, and the ratio of their first-order modal damping ratios is up to 19. The noise reduction effect of the I-beam with CLD is around 10 dB; moreover, the vibration reduction effects in vertical and lateral directions are more than 10 dB. The noise of the I-beam is dominated in the frequency range higher than 250 Hz, and the spectral characteristics of vibration and noise are accordant. The noise reduction effect of the I-beam with CLD is obvious in the frequency range higher than 80 Hz and it reaches to a maximum in 1000 Hz. The lateral and vertical vibrations of the I-beam with CLD are reduced in the frequencies higher than 80 Hz and 125 Hz, respectively. It is observed that the vibration near the loading location is well reduced.????