转子在临界转速点的振动和阻尼比的估计方法

以单盘对称转子模型为分析对象,分析转子在临界转速点时的振动,导出共振过程的数学模型。提出了两种识别转子阻尼比的新方法:a.利用衰减自由振动信号,构造关于其包络的误差函数,通过迭代法使误差函数达到最小来估计阻尼比,该方法相比对数衰减率法可以更加准确地估计转子的阻尼比;b.利用幅频曲线识别转子阻尼比,即根据转子实测的增减速过程振动数据,利用最小二乘法预估阻尼比的初值,再利用寻优法确定转子的阻尼比。通过试验检验,证明这两种估计阻尼比的方法能够较有效地解决阻尼比估计不准的实际问题。

Vibration of Rotors at Critical Speed and Estimation Method of Damping Ratio

Taking the symmetrical single-disk rotor model as research object,the vibration of the rotor running at critical speed is studied and development of resonance is deduced.Two methods for identifying damping ratio of the rotor are proposed.In the first method,which uses the decay signals of free vibration,error function is constructed based on the envelope of the curve.Iteration method is used to minimize the error function,which can identify damping ratio more accurately then logarithmic decrement method.Amplitude-frequency curves of rotor,which is drawn according to the measured vibration data of transit process,is applied in the second method.Least square method is used to predict damping ratio,then,optimization method is utilized to determine the damping ratio.Experimental results show that both estimation methods can estimate damping ratio effectively and solve the practical problems.