电磁谐振式疲劳试验系统恒载荷控制方法研究

RESEARCH OF CONSTANT-LOAD CONTROL METHOD FOR ELECTROMAGNETIC RESONANT FATIGUE TEST SYSTEM

为研究电磁谐振式弯曲疲劳试验中试件的裂纹扩展对谐振系统振动特性的影响,利用有限元软件Abaqus对系统进行了不同裂纹尺寸下的模态和强迫振动分析。根据多种裂纹尺寸条件下的分析结果,建立了试件裂纹尺寸、摆臂加速度、试件应力水平之间的关系。讨论了为实现系统恒载荷控制,在试验过程中对激振力的大小进行调整的必要性,提供了以振动加速度为参考对激励电流的幅值进行调整来进行恒载荷控制的方法。

In order to study the influence of testee＇ s crack growth on the vibration character of the system during the electromagnetic resonant fatigue testing, detailed FEA for modal and forced vibration with testees at different crack sizes were conducted. According to the results of the analysis, the dynamic relationships between the acceleration of the swing arm and the stress of the testee at different crack sizes are set up. The FEA results show that as the crack growing, the natural frequency and vibration character change accordingly, so it is necessary to change the exciting force to meet constant-load control request during the test. Finally, a method using the acceleration signal as the reference is proposed to achieve constant-load control.