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Nondestructive Estimation of Stress and flaws by combining Magnetic Field and Ultrasonics

结合磁场和超声波对应力和缺陷进行无损评估

基本信息

批准号：
06650105
负责人：
MATSUMOTO Eiji
金额：
$ 1.22万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

The purpose of the subject is to develop the magnetoacoustic nondestructive techniques proposed by the investigators in order to include the cases of strong stresses and fractures. The obtained result during the term of the project is the followings.1. Stress evaluation by MagnetoacoustoelasticityWe showed that it is possible to separate the texture and the acoustic anisotropy in the speed change of ultrasonic waves by applying a suitable magnetic field. We proposed new technique of plane stress evaluation only by longitudinal waves by choosing the applied magnetic field.2. Magnetoacoustic Emission (MAE) under the stressWe applied the stress to the magnetic material (low carbon steel) up to the plastic region, and measured MAE at each stress level under the periodic change of the magnetic field. The total count of MAE signals during one cycle of the magnetic field, is found to decrease according to the stress in the elastic region. In a result, the nondestructive evaluation of the stress using MAE is suitable for low stress levels in the elastic region. In addition to the extension test, we also measured the stress dependence of MAE under compression test. It is shown that the MAE count during one cycle of the magnetic field is symmetry with respect to the sign of the uniaxial stress. Possibility of flaw estimation by MAE is left as a future subject.3. Constitutive Equations of the magnetic materialsAs for the rate dependence of the magnetization, we proposed a rate type constitutive equation and verified that the indential response of the magnetization agrees with the experimental data. We also created the experimental instrument of two-dimensional magnetization tests. We showed that the proposed three-dimensional constitutive equations with nonlinear, anisotropic and hysteretic effects well describes the experimental results of magnetization under rotating magnetic field.

本课题的目的是发展研究者提出的磁声无损检测技术，以包括强应力和断裂的情况。项目实施期间取得的成果如下：1.通过磁声弹性应力评价我们表明，通过施加适当的磁场，可以在超声波的速度变化中分离织构和声学各向异性。通过选择外加磁场，提出了仅用纵波进行平面应力评估的新技术.应力作用下的磁声发射（MAE）我们对磁性材料（低碳钢）施加应力直至塑性区，在周期性变化的磁场作用下测量各应力水平下的MAE。在一个周期的磁场中，MAE信号的总计数，被发现减少根据在弹性区域中的应力。因此，使用MAE的应力的无损评价是适合于在弹性区域中的低应力水平。除了拉伸试验外，我们还测量了压缩试验下MAE的应力依赖性。结果表明，在一个周期的磁场MAE计数是对称的单轴应力的符号。利用MAE进行缺陷估计的可能性是未来的研究课题.磁性材料的本构方程对于磁化强度的速率依赖性，我们提出了一个速率型本构方程，并验证了磁化强度的指数响应与实验数据的一致性。研制了二维磁化测试实验装置。结果表明，所提出的具有非线性、各向异性和滞后效应的三维本构方程能够很好地描述旋转磁场下磁化强度的实验结果。