Research On Giant Magneto-impedance Effect Of Space Morphology Of Ferromagnetic Amorphous Wire

Ferromagnetic amorphous wire(abbreviated as amorphous wire)has a Giant Magnetoimpedance(GMI)effect.Under an external DC magnetic field,its impedance changes with the magnetic field and applied stress,and has high sensitivity and response.Speed,has important application value in the field of woven composite material health monitoring.This thesis takes Co-based amorphous wire as the research object,uses a variety of equipment such as mechanics and magnetism to test the basic characteristic parameters,through a combination of numerical analysis and experiments,and combines the plain weaving process and the fourstep weaving process to explore one-dimensional The influence law of the internal stress of the amorphous wire on the GMI effect in the multi-dimensional shape.First of all,starting from a single amorphous wire,the basic theory of GMI effect of amorphous wire is analyzed and it is found that geometric parameters have a certain influence on its GMI effect.Combined with the theory of elasticity,the tensile stress and bending stress in onedimensional form are established.The relationship model between wire diameter and length parameters,through numerical analysis results,found that when the external excitation frequency is 1MHz/10MHz/20 MHz,the GMI effect of amorphous wire increases first and then decreases with the increase of external tensile and bending stress.When the stress reaches a certain value,the GMI effect is weaker than that in the unstressed state.Secondly,starting from the analysis of the experimental plan,a special device for fixing the amorphous wire is designed.After applying different tensile/bending stresses to the amorphous wire,the device is used to fix the force state and then placed in the Helmholtz coil.A precision impedance analyzer was connected to test the GMI effect of amorphous wires under different stress states and magnetic field strengths.The results show that at the frequency of 1MHz/10MHz/20 MHz,compared with the initial state,when the amorphous wire is subjected to tensile/bending stress,the GMI effect shows a trend of gradually increasing and then decreasing with the increase of stress,which proves The correctness of the numerical analysis results.Finally,by analyzing the spatial morphology formed by the amorphous wire under the plain weaving process and the four-step weaving process,the spatial morphological function model is established,and the two-dimensional and three-dimensional morphological fixed molds are made through 3D printing according to the spatial morphological function.Then,the amorphous wire was embedded in the two-dimensional and three-dimensional fixed molds,and the amorphous wire under different stress states was fixed by a fixing device,and the GMI effect of the amorphous wire was tested.The results show that: compared to the onedimensional shape,the amorphous wire in the two-dimensional shape can produce roughly the same rate of change in the GMI effect when subjected to a smaller tensile stress;compared with the one-dimensional shape and the two-dimensional shape,the three-dimensional shape It shows a higher GMI effect value as a whole,and its sensitivity to deformation under stress is higher.A smaller stress can produce greater changes in the GMI effect value than under onedimensional and two-dimensional forms.This article starts with one-dimensional shape,reveals the influence of tensile and bending stress on the GMI effect of Co-based amorphous wire,gradually expands to two-dimensional and three-dimensional shapes,and finally analyzes the stress state of Co-based amorphous wire in a typical spatial shape.The law of influence on the GMI effect provides theoretical support for the use of amorphous wire in the monitoring of the stress state of braided composite materials and the prediction of damage.