This paper details the creation of a device capable of generating a powerful and consistent static magnetic field. This apparatus serves the purpose of quantifying the magnetostrictive strain found in materials like a...This paper details the creation of a device capable of generating a powerful and consistent static magnetic field. This apparatus serves the purpose of quantifying the magnetostrictive strain found in materials like annealed cobalt ferrite and Terfenol-D, specifically those shaped as cylindrical rods. In our investigation, the use of static magnetic fields proves most advantageous. This choice is made to mitigate the generation of eddy currents, which would inevitably occur if the magnetic field intensity were varied. The fundamental idea behind this design involves employing a C-shaped iron core constructed from low-carbon mild steel. On this core, three coils are mounted, each capable of producing one-third of the required 9000 Oersted (Oe) magnetic field strength. The test specimen is situated within the “jaws” of the C-shaped core, thus completing the magnetic circuit. To manage the heat generated by each coil, a cooling system consisting of copper tubes is employed. These tubes facilitate the flow of air to dissipate the heat. To model and predict the magnetic field strength produced by the coils, finite element analysis (FEMM) software is utilized, and the results align closely with the anticipated outcomes. This design effectively generates a robust and unchanging magnetic field measuring a stable 9000 Oe in total. Consequently, this equipment finds utility in characterizing the magnetic properties of specific materials.展开更多
To test the magnetic signals leaked from the surface of specimens during loading, the experiments of the static tensile of medium carbon 45# steel were carried out. The results show that the magnetic field strength va...To test the magnetic signals leaked from the surface of specimens during loading, the experiments of the static tensile of medium carbon 45# steel were carried out. The results show that the magnetic field strength values rapidly vary when the load began, and the curves of the magnetic field strength change from irregularity to regularity with the increase of the load. Furthermore, by comparing with the state of on-line testing, it is found that the magnetic signals of out-of-line testing has more practicability. In the course of loading, though the dots of passing zero of the magnetic field strength continually changed their positions and quantities, the last rupture places were always approached by the dots of passing zero since the elastic loading phase. Some certain relations should exist between external stress and changing of magnetic signals inside the material, and correlative explanation is made based on dislocation theory and the mechanism of magnetic domain action, which provides the basis for further research of magnetic memory.展开更多
文摘This paper details the creation of a device capable of generating a powerful and consistent static magnetic field. This apparatus serves the purpose of quantifying the magnetostrictive strain found in materials like annealed cobalt ferrite and Terfenol-D, specifically those shaped as cylindrical rods. In our investigation, the use of static magnetic fields proves most advantageous. This choice is made to mitigate the generation of eddy currents, which would inevitably occur if the magnetic field intensity were varied. The fundamental idea behind this design involves employing a C-shaped iron core constructed from low-carbon mild steel. On this core, three coils are mounted, each capable of producing one-third of the required 9000 Oersted (Oe) magnetic field strength. The test specimen is situated within the “jaws” of the C-shaped core, thus completing the magnetic circuit. To manage the heat generated by each coil, a cooling system consisting of copper tubes is employed. These tubes facilitate the flow of air to dissipate the heat. To model and predict the magnetic field strength produced by the coils, finite element analysis (FEMM) software is utilized, and the results align closely with the anticipated outcomes. This design effectively generates a robust and unchanging magnetic field measuring a stable 9000 Oe in total. Consequently, this equipment finds utility in characterizing the magnetic properties of specific materials.
文摘To test the magnetic signals leaked from the surface of specimens during loading, the experiments of the static tensile of medium carbon 45# steel were carried out. The results show that the magnetic field strength values rapidly vary when the load began, and the curves of the magnetic field strength change from irregularity to regularity with the increase of the load. Furthermore, by comparing with the state of on-line testing, it is found that the magnetic signals of out-of-line testing has more practicability. In the course of loading, though the dots of passing zero of the magnetic field strength continually changed their positions and quantities, the last rupture places were always approached by the dots of passing zero since the elastic loading phase. Some certain relations should exist between external stress and changing of magnetic signals inside the material, and correlative explanation is made based on dislocation theory and the mechanism of magnetic domain action, which provides the basis for further research of magnetic memory.
