基于ACSM法的铁磁构件应力表征

Ferromagnetic Components Stress Characterization Based on ACSM

大型机械设备的关键铁磁构件服役工况恶劣,易形成应力集中并可能导致疲劳累积损伤、裂纹等破坏性缺陷,因此准确评价铁磁构件的应力集中程度可有效防止危险性缺陷的产生。研制了用于测量应力的交变磁场应力测量法（Alternating current stress measurement,ACSM）系统,其硬件部分包括检测探头、激励模块、信号调理电路和信号采集模块等,信号采集系统基于LabVIEW软件设计。对Q235钢进行静态应力检测,通过分析检测传感器二维信号的变化特征,研究不同应力程度、激励磁场与应力方向夹角a和激励频率f对ACSM检测信号的影响。试验结果表明:随应力的增加,仅△UBx呈线性逐渐增大;激励磁场与应力方向相同时（α=0°）,△UBx最大值为160 mV,并随α角的增加逐渐变大,当α=90°时达到最大值270mV;当f≤3kHz时,检测信号△UBx随激励频率的增加呈递增趋势,而f（29）3 k Hz时,检测信号趋于稳定或减小。

The key ferromagnetic components in large-scale machinery and equipment are in poor working condition, easy to form stress concentration, and may lead to fatigue damage and crack damage. The accurate evaluation of the degree of stress concentration of ferromagnetic components can effectively prevent the occurrence of dangerous defects. The ACSM system for measuring stress is developed. The hardware part of the system includes the detection probe、excitation module、the signal conditioning circuit and the signal acquisition module. The signal acquisition system is designed based on LabVIEW software.The static stress of Q235 steel is tested. The influence of different stress levels, angle between excitation magnetic field and stress direction and excitation frequency on ACSM detection signal is studied by analyzing and detecting the change characteristics of two-dimensional signal of probe.The experimental results show that only △UBx increases linearly with the increase of stress. When the excitation magnetic field is the same as the stress direction（α=0°）, the maximum △UBx is 160 mV and becomes larger with the increase of α, Maximum 270 mV when α=0°. When f equal or less than 3 kHz, the detection signal △UBx increases with the increase of excitation frequency, otherwise the detection signal tends to be stable or reduced.