拉杆转子界面局部脱开识别的改进广义柔度矩阵法

摘要

A method of detecting partial separation of interface in rod-fastened rotors is developed based on the generalized flexi-bility matrix method.The original generalized flexibility matrix method can be used to identify the structural damage with the first mode.However,separation of interface in rod-fastened rotors can't be detected by generalized flexibility matrix method. Firstly,the contact stiffness of interface varies as the rotating speed changes,so the first and second modal parameters ob-tained are corresponding to different contact conditions.Secondly,with the effect of factors such as the gyroscopic effect and spin softening,the critical speed of the rotor and the vortex trajectory are not equal to the natural frequency and mode shape, respectively.The generalized flexibility matrix method is improved by shape restraint so that any single mode can be used to detect the damage of the rotor.In addition,the variation of the critical speed and vortex trajectory caused by partial separation of interface,combined with the natural frequency and mode shape of the rotor are used to identify the location and degree of the damage.Finally,this method is tested through a rod-fastened rotor with multiple damage scenarios.%燃气轮机拉杆转子在拉杆预紧松弛时,重力、振动及热变形等因素都可能导致轮盘非连续界面的局部分离.拉杆转子各界面上弯矩随着转速改变而变化,通过不同阶次临界转速时各界面的接触状态可能不同,因此只能使用对应阶次的模态参数对界面分离发生的位置和程度进行识别.使用振型约束的方式对损伤识别的广义柔度矩阵法进行了改进,能够使用任意单阶模态参数识别结构的损伤.利用拉杆转子临界转速和振型的变化量,结合其静止时的模态参数,使用所提出方法对界面脱开进行识别,结果表明该方法能够得到界面局部脱开的位置和程度.