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铁磁材料被交变磁场局部磁化以后 ,局部的体积磁畴产生错动 ,释放一种物理效应 ,即磁弹噪讯。它是由德国物理学家巴克豪森 (BarkhausenH)于 1919年发现的 ,称之为MagneticBarkhausenNoise或Magneto -elasticityNoise,简记MBN。试验发现 ,该噪讯强烈地依赖于材料的组织结构和受力状态。万分之几材料参数变化都会引起MBN的变化。依据铁磁材料磁化 ,受力释放的噪讯 ,研制了利用磁弹噪讯技术检测残余应力的仪器。根据磁弹噪讯随拉应力的增加而增大 ,随压应力的增加而减少 ,采用零点标定技术绘制MBN -σ标定曲线 ,以对应标定曲线的MBN值确定测试的应力值。试验检测了焊接结构件残余应力的大小及分布。为工程应用提供了一种可行的检测技术。
After the ferromagnetic material is partially magnetized by the alternating magnetic field, local volumetric magnetic domains are misplaced and release a physical effect, that is, magnetic bomber noise. It was discovered in 1919 by the German physicist BarkhausenH, calling it MagneticBarkhausenNoise or Magneto-elasticityNoise, shortly MBN. The test found that the noise strongly depends on the material structure and stress state. Very few changes in material parameters will cause MBN changes. Based on the magnetization of ferromagnetic materials, the force release of noise, developed using magnetic noise technology to detect residual stress instrument. According to the increase of tensile stress, magnetic noise increases with the increase of tensile stress and decreases with the increase of compressive stress. The calibration curve of MBN-σ is plotted by zero calibration technique to determine the test stress value corresponding to MBN of calibration curve. The test detects the size and distribution of residual stress in the welded structure. For engineering applications provides a viable detection technology.