Studies on Practical Application of Magnetic Sensor using Rotational Magnetic Flux and Non-destructive Testing System

对旋转磁通磁传感器和无损检测系统的实际应用进行了研究。结果摘要如下所示。(1)利用旋转磁通的磁传感器无损检测。在传统的涡流无损检测中，磁传感器是由直流或交流电驱动的。因此，磁性材料中产生的磁场是单向排列的。然而，为了估计未知缺陷的形状或位置，需要二维交变磁通密度矢量。我们提出了旋转磁通无损检测系统。在该系统中，得到缺陷的幅值和相位值作为缺陷的信号。(2)带神经网络的旋转磁传感器，用于无损检测。在传感器在无损检测系统中的应用中，我们提出了一种新的基于神经网络的无损检测方法。在该系统中，测量了幅值和相位值，并使用了更多的方法来获取缺陷的信息。这些值包括关于未知缺陷的形状或位置的信息。我们将神经网络技术应用于缺陷形状的估计。在一个简单的例子中，我们报告了估计的缺陷与给定的缺陷很好地吻合。(3)应力磁性材料中巴克豪森噪声的声学分析。由于磁性材料的疲劳增加被认为是材料击穿的原因，因此开发在击穿前检测疲劳的技术非常重要。对于磁性材料缺陷的无损检测，我们注意到铁磁性材料在磁化过程中存在巴克豪森噪声。我们研究了热疲劳材料试样噪声的声学分析。在声学分析中，进行了波形功率计算、过零率分析和频率分析。结果表明，材料的疲劳性能与噪声的频谱特征密切相关。我们已经报道了随着试件疲劳程度的增加，巴克豪森噪声变得与白噪声相似。少

Studies on practical application of the magnetic sensor using rotational magnetic flux and non-destructive testing (NDT) system have been curried out. The summary of the results is shown below. (1) Nondestructive testing with magnetic sensor using rotational magnetic flux.In conventional eddy current NDT's, the magnetic sensor has been driven by dc or alternative current. Therefore, the generated magnetic field in magnetic materials is arranged in one direction. However, in order to estimate shape or position of an unknown defect, a two-dimensional alternating magnetic flux density vector is necessary. We have proposed the NDT system using rotational magnetic flux. In this system, the magnitude and phase value are obtained as the signals of defect. (2) Rotational magnetic sensor with neural network for non-detractive testing.In application of the sensor for NDT system, we have developed a new NDT method with neural network. In this system, the magnitude and phase value are measured and … More used to obtain information about defect. These values include the information about the shapes or positions of an unknown defect. We applied a neural network technique to estimation of a defect shape. We have reported that the estimated defects show good agreement with the given one in a simple example. (3) Acoustic analysis of the Barkhausen noise in stressed magnetic material.Because increase of fatigue in magnetic materials is known as a cause of breakdown of material, developing techniques in detecting fatigue before breakdown are very important. For the detection of flaw in the magnetic materials with NDT, we notice the Barkhausen noise occurred in magnetizing proses of ferromagnetic materials. We have investigated acoustic analyses of the noise on sample materials with thermal fatigue. As acoustic analyses, obtaining power of the waveform, zero crossing rate analysis and frequency analysis are performed. These results showed that the fatigue of the materials and spectral feature of the noise were closely concerned. We have reported that The Barkhausen noise gets similar to the white noise with increasing the fatigue of the specimen. Less