涡流技术在应力检测中的应用  

Test of Applied Stress Using Eddy Current Technology

作　　者：陶大锦[1] 林晓雷[1] 朱丹峰[1] 

机构地区：[1]温州医学院信息与工程学院,浙江温州325035

出　　处：《机床与液压》2013年第4期137-139,共3页Machine Tool & Hydraulics

摘　　要：残余应力是造成零件疲劳、断裂的重要因素,有效评价应力状态对于关键部件的早期失效预测十分必要。设计了均匀分布的应力场,采用涡流检测仪器对不同程度的应力分布场进行测试,在阻抗分析法原理的基础上,研究涡流有效电压值随应力的变化情况。通过对铝合金2A12进行了拉伸应力试验,结果表明,涡流信号随着试样内部应力场的增大呈线性变化的趋势,此特征可以用于评估材料应力所处的状态。最后试验研究了涡流信号大小与线圈激励电流频率的关系,结果表明,在低频区,涡流信号随着频率增大而增大,当激励频率比较高时,由于趋肤效应的作用,使得涡流信号随着频率的增大产生衰减。因此检测残余应力时选择合适的激励频率十分关键。Residual stress was one of the factors that caused fatigue and defects in critical components, and effective evaluation of stress status was very necessary for forecasting forepart lapse of critical components. The uniform distributed stress field was de signed, and the stress field of different degree was tested by using eddy current testing instruments, then the changing instance of ef fective voltage of eddy current along with stress were studied based on the principle of impedance analyzing method. By the elongation stress experiment on the aluminum alloy of 2A12, the results showed that the amplitude of the eddy current is increased linearly along with the increasing of the internal applied stress of samples, and this characteristic could be used to evaluate stress status in materials. Finally the relation between exciting current frequency of coils and magnitude of eddy current was studied by the experiments. The re sults show that at low frequency, the eddy current signal is increased along with increasing of frequency. When the exciting frequency is relatively high, owing to the influence of skin effect, the amplitude of the eddy current is decreased along with the increasing of fre quency. So choosing the proper exciting frequency is very critical for testing of residual stress.

关 键 词：应力 涡流 激励频率 

分 类 号：TH123.4[机械工程—机械设计及理论] TG115.28[金属学及工艺—物理冶金]