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干摩擦装置常用于透平叶片以便于增加阻尼和减小振动应力。为了研究具有干摩擦阻尼结构叶片的振动特性,设计并建造了相应的实验台,采用激光测振仪和电涡流传感器等仪器测试了具有干摩擦阻尼围带结构叶片的振动特性,获得了不同围带正压力和激振力作用下叶片的振动频响曲线和模态阻尼比。实验结果表明:在一定的激振力作用下,叶片的共振频率随着围带正压力的增加而增大,其中存在一个最优围带正压力使叶片的共振响应幅值最小、模态阻尼比最大,从而达到最好的摩擦阻尼减振效果,并通过实验确定了叶片围带最优正压力的范围;此外,由于系统具有非线性特性的干摩擦阻尼,在一定的围带正压力作用下,叶片的共振频率随着激振力幅值的增加而降低,模态阻尼比随着激振力幅值的增加而增大。
Dry friction devices are commonly used on turbine blades to increase damping and reduce vibrational stresses. In order to study the vibration characteristics of the blade with the dry friction damping structure, a corresponding test bench was designed and constructed. The vibration characteristics of the blade with the dry friction damped shrouded structure were tested by laser vibrometer and eddy current sensor, Vibration frequency response curve and modal damping ratio of blades under positive pressure and exciting force. The experimental results show that the resonance frequency of the blade increases with the increase of the positive pressure of the shrouded belt under a certain excitation force, and there is an optimal zone with a positive pressure so that the resonance amplitude of the blade is the smallest. The modal damping Than the maximum, so as to achieve the best damping effect of friction damping, and through experiments to determine the optimal positive pressure range of blade shroud; In addition, due to the system has a nonlinear friction properties of dry friction, a certain role in the surrounding area positive pressure , The resonant frequency of the blade decreases with the amplitude of the exciting force and the mode damping ratio increases with the amplitude of the exciting force.