铁磁试件应力集中疲劳损伤的磁适应检测与评价技术

Magnetic adaptation detection and evaluation technology for stress concentration fatigue damage of ferromagnetic test pieces

磁适应检测技术是通过对试件微分磁导率极大值的检测,对构件的应力集中状况和疲劳损伤程度进行早期评价的新方法。文中研究了待测构件的磁导率与检测信号的关系模型,证明了检测信号与微分磁导率有关。从试验上测定了35钢的低场初始磁化曲线,发现对35钢初始磁导率即为极值微分磁导率。研制了磁适应检测的试验平台。通过试验优化了激励频率,激励频率取200 Hz。对35钢平板试件检测信号随拉应力的关系进行了测试研究,试验表明,检测信号具有很好的规律性和稳定性。说明磁适应检测技术是一种新的可早期检测应力集中和损伤程度的方法,具有广阔的应用前景。

The magnetic adaptation detection technique is a new method for early evaluation of stress concentration and fatigue damage degree of components through the detection of the maximum differential permeability of test pieces.In this paper,the relationship model between the permeability of the component to be measured and the detection signal is studied,and it is proved that the detection signal is related to the differential permeability.The low-field initial magnetization curve of 35 steel is measured experimentally,and it is found that the initial permeability of 35 steel is the extreme differential permeability.A test platform for magnetic adaptation detection is developed.The excitation frequency is optimized by experiments,and the excitation frequency is 200 Hz.The relationship between test signals and tensile stress of 35 steel plate test pieces is tested and studied.The test results show that there are good regularity and stability on test signals.It indicates that the magnetic adaptation detection technology is a new method to detect stress concentration and damage degree in the early stage and enjoys a broad application prospect.