用磁声法MAE检测钢结构构件应力的机理和应用

The mechanism and application of magnetoacoustic method testing stress for steel structure

分析了磁声发射的产生与接收、磁声发射与磁致伸缩、磁声发射的应力检测机理,应力对磁声发射的影响,磁声发射的检测系统等几个方面.从这些方面说明了用磁声发射来实施应力检测是可行的.证明磁声发射的强度既受外磁场变化影响,又受应力变化影响,并且磁声发射的变化幅度与所受应力大小有一定的关系,据此可为磁声发射检测铁磁材料的应力状态提供依据.但由于磁声发射的强度和施加于构件上应力状态的关系比较复杂,所以结合磁声发射和巴克豪森BN两种方法各自优点的应力检测更比看好.

Steel materials is a sort of ferromagnetic materials, so MAE can be used as a new methods for nondestructive testing of internal stress for steel structure ＆ member. Several factors are analyzed and described in the paper, there are MAE producing and being received, MAE and magnetostriction, the mechanism of magneto acoustic emission method testing stress, the influence between MAE and stress, MAE measuring system, etc. From these aspects, it can be concluded that the application of MAE to measure the internal stress for steel structure ＆ member is feasible. Similarity, when the ferromagnetic materials undergoes internal stress changes due to external loads or residual stress, the domain walls movement will be influenced. Thus, the variation of the intensity of MAE is influenced both by stress and by applied magnetic field, and there are a certain relationship between amplitude of MAE and applied stress, which provides a basis for the detection of the stress state in ferromagnetic materials. But the relation of the intensity of MAE and upon its stress conditions is more complicated, the stress measuring method based on magneto acoustic emission is developed by making use of the advantage of MAE and BN and with the specific features of their application in the stress measurement of ferromagnetic materials taken into consideration.