基于过渡过程信号的振动机机体结构裂纹故障检测

Research on Crack Fault Detection of Vibration Machine Body Structure Based on Transition Process Signal

目的 研究含裂纹的振动机机体结构在启动这一短时过渡过程中各个动力学响应随裂纹程度变化的趋势,为振动机机体结构的裂纹故障早期诊断研究提供理论参考。方法 将复杂的非线性振动结构问题通过等效建立模型、动力学分析求解、时频域信号分析相结合进行研究,模拟不同的启动初始输入运动信号、不同裂纹位置的情况;编制龙格-库塔VB程序并模拟不同裂纹大小程度来求解该动力学模型,得出位移、速度、加速度等响应的时域图与频域图,并进行对比分析。结果 在时域内过渡过程振动响应的周期与振幅会随裂纹程度增大而增大,在频域内振动响应会随裂纹程度增大而出现“频幅增大”、“频率成分新增”、“移频”的变化规律。结论 通过多角度对比证明,可以将各响应在时域与频域的变化作为故障诊断的判别依据,判断是否含有机体裂纹故障及故障的程度。

The paper is proposed to study the trend of the dynamic response of the cracked vibrating body structure with the crack degree during the short-term transition process of starting,so as to provide a theoretical reference for the early diagnosis of crack faults in the vibrating body structure.The complex nonlinear vibration structure problem is studied by equivalent modeling,dynamic analysis and time-frequency domain signal analysis.We simulate different initial input motion signals and different crack positions,compile Runge-Kutta VB program and simulate different crack sizes to solve the dynamic model.The time and frequency domain diagrams of displacement,velocity,acceleration and other responses are obtained to carry out comparative analysis.The results show that the period and amplitude of the vibration response in the time domain will increase with the increase of the crack degree.In the frequency domain,the vibration response will appear as the crack degree increases,and there will be“increased frequency amplitude”,“new frequency components”,and“frequency shift”changes.It can be concluded that through multi-angle comparison,it is proved that the changes in the time domain and the frequency domain of each response can be used as the basis for fault diagnosis to determine whether there are crack faults and the extent of the fault.