新型阻尼结构叶片振动特性试验研究

干摩擦阻尼结构被广泛应用于透平叶片中来降低其振动应力。文章设计并搭建了干摩擦阻尼块结构叶片振动特性测试试验台，通过测量一新型阻尼结构叶片的振动响应值，获得了不同激振力及模拟离心力转速下叶片频率响应曲线及模态阻尼比。试验结果表明：当激振力较小时（4N、5N和6N），叶片的共振频率随模拟离心力转速的上升而不断增加，而模态阻尼比则先增加再减小，在40％模拟离心力转速工况下模态阻尼比最大，叶片减振效果最好；当激振力较大时（12N、18N和24N），叶片振动更加剧烈，使得阻尼块接触刚度降低，叶片的共振频率接近自由叶片固有频率，而模态阻尼比随着模拟离心力转速的上升不断降低。

Experimental Study on Vibration Characteristics of Blade with New Damping Structure

Dry friction damping structure had been widely used in turbine blades to decrease the vibration stress. A test rig was designed and built to test the vibration characteristics of blades with dry friction dampers, The vibration response of a real blade with wedge dampers were measured. The response curves and modal damping ratios of the blade under different excitation forces and simulating centrifugal force due to different rotational speeds were obtained. The experimental results showed that with the increase of simulating centrifugal force of rotational speed, the resonance frequency of the blade increased and the modal damping ratio experience an increase period followed by a decrease period under the applied small excitation forces（4N, 5N and 6N）.The modal damping ratio reached maximum and the best damping effect was attained as the simulating centrifugal force of rotational speed is 40%. It was also seen by the experimental results that the resonance frequency of the blade was close to that of the free blade under the applied big excitation forces（12N, 18N and 24N） for the contact stiffness of the dampers decreased with excessive vibration. And the modal damping ratio decreased with the increase of the simulating centrifugal force of rotational speed.