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

对旋转磁通磁敏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)基于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沿一个方向排列。然而，为了估计未知缺陷的形状或位置，需要一个二维交变磁通密度矢量。提出了基于旋转磁通的无损检测系统。在该系统中，以幅值和相位值作为缺陷信号。(2)基于神经网络的旋转式磁性传感器的无损检测。将该传感器应用于无损检测系统中，提出了一种基于神经网络的新型无损检测方法。在该系统中，测量了幅值和相位值，并进行了…更多用于获取有关缺陷的信息。这些值包括有关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。我们已经报告了，在一个简单的例子中，估计的缺陷与给定的缺陷显示出很好的一致性。(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中疲劳的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是非常重要的。在对磁性材料进行无损检测时，我们注意到铁磁材料的磁化过程中存在巴克豪森噪声。对热疲劳试件上的噪声进行了声学分析。作为声学分析，进行了波形功率的获取、过零率分析和频率分析。这些结果表明，材料的疲劳与噪声的频谱特征密切相关。我们已经报道，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。较少

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