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Nondestructive evaluation of advanced materials by use of electromagnetoacoustic interactions

利用电磁声相互作用对先进材料进行无损评估

基本信息

批准号：
12650085
负责人：
MATSUMOTO Eiji
金额：
$ 2.18万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

As the foundation of the present research, we formulated various magnetomechanical behaviors of ferromagnetic materials with magnetoelastic couplings. We extended the magnetomechanical constitutive equation proposed by Matsumoto to include the dependence of magnetic histories as internal variables for wider classes of ferromagnetic materials. Applying the constitutive equations to typical ferromagnetic materials, we have shown that they can describe in good accuracy the magnetization curve, the magnetostriction curve including their stress dependence, hysteresis and nonlinearity.We next applied the magnetoacoustic effects to the nondestructive evaluation of the stress and the magnetization. When the magnetic field is applied to a ferromagnetic material, the acoustic anisotropy is induced in the direction of the magnetization vector. Then the direction of the magnetization vector can be estimated by measuring the speed of the transverse wave polarized in each direction. The difference o … More f the maximum and the minimum speeds has a strong correlation with the acoustic anisotropy, so that the magnitude of the magnetization vector can be also estimated. Such a nondestructive measurement of the magnetization can be applied to verification of the electromagnetic analysis, which contributes to more accurate and effective design of electromagnetic instruments. It is also shown that conventional acoustoelastic measurement enables us to evaluate plane stress if the magnetic field is applied.As another application of electromagnetoacoustic interactions, we visualized the internal defects by ultrasonic inspection using electromagnetic acoustic transducer (EMAT). We first simulated the transmitting and the receiving processes of EMAT by the wave analysis and the electromagnetic analysis. An ultrasonic image of defects can be obtained by scanning EMAT near the specimen surface. Improvement of the ultrasonic image was studied by employing smoothing, deconvolution and damping effect as waveform analysis, and SAFT-UT and ALOK techniques as scanning method. Less

作为本研究的基础，我们阐述了磁弹性耦合下铁磁材料的各种磁力学行为。我们扩展了由松本提出的磁力本构方程，使其包含了作为内部变量的磁历史的依赖关系，适用于更广泛的铁磁材料。将本构方程应用于典型的铁磁材料，可以很好地描述材料的磁化曲线、磁致伸缩曲线及其应力依赖性、磁滞和非线性，并将磁声效应应用于应力和磁化的无损评价。当磁场被施加到铁磁材料时，在磁化矢量的方向上感生声学各向异性。然后，磁化矢量的方向可以通过测量在每个方向上极化的横波的速度来估计。区别O ...更多信息 f的最大和最小速度与声学各向异性具有很强的相关性，从而也可以估计磁化矢量的大小。这种磁化强度的无损测量可以应用于电磁分析的验证，这有助于更准确和有效地设计电磁仪器。作为电磁声相互作用的另一个应用，我们利用电磁超声换能器（EMAT）对材料内部缺陷进行了超声检测。本文首先通过波形分析和电磁场分析对电磁超声换能器的发射和接收过程进行了仿真。缺陷的超声图像可以通过扫描试样表面附近的EMAT获得。采用平滑、去卷积和阻尼效应作为波形分析，SAFT-UT和ALOK技术作为扫描方法，对超声图像进行了改善研究。少