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以带疲劳裂纹悬臂梁为例研究疲劳裂纹对叶片固有频率及强迫振动响应的影响。应用传递矩阵法求解裂纹叶片振动响应，选用余弦函数模拟疲劳裂纹的开合过程，理论分析了裂纹叶片的非线性振动特性，并进行裂纹试件实验。理论分析及实验结果都表明疲劳裂纹不仅使悬臂梁的固有频率下降，而且引起强迫振动响应的非线性特征。最后，就叶片裂纹故障监测特征量的选取做了分析、讨论。
Taking fatigue cracked cantilever beam as an example, the influence of fatigue crack on natural frequency and forced vibration response of blade was studied. The transfer matrix method was used to solve the vibration response of the cracked blade. The cosine function was used to simulate the opening and closing process of the fatigue crack. The nonlinear vibration characteristics of the cracked blade were theoretically analyzed and the cracked specimen was tested. Theoretical analysis and experimental results show that the fatigue crack not only reduces the natural frequency of the cantilever beam but also induces nonlinear characteristics of the forced vibration response. Finally, the selection of the characteristic quantity of the blade crack monitoring is analyzed and discussed.