Thermal Demagnetization Characteristics of Nd-Fe-B Used in Eddy Current Recoil Mechanism of Artillery
Permanent magnet eddy current recoil brake is an innovative design in the field of efficient control of recoil resistance of artillery.In the application scenario of artillery with high energy consumption density and relatively closed working environment,there is a serious temperature rise in the eddy current recoil brake.High temperature will lead to the decrease in the magnetic properties of Nd-Fe-B materials and then affect the recoil characteristics.At present,the thermal demagnetization process of Nd-Fe-B is not clear and lacks theoretical expression.In order to grasp the thermal demagnetization characteristics of Nd-Fe-B,the demagnetization process of NdFeB at different temperatures is quantitatively analyzed from the perspective of microscopic magnetic moment heating motionbased on the micromagnetic simulation method,and the demagnetization curve of macroscopic Nd-Fe-B is obtained.In order to use the demagnetization curve for better guiding the engineering design,the J-A model is used to describe the demagnetization behavior of Nd-Fe-B,and the experimental verification is carried out.The magneto-thermal coupling numerical calculation of demagnetization and resistance degradation of Nd-Fe-B is carried out based on the traditional residual magnetic flux density model and the J-A model.By comparing with the experimental results of the prototype,it is found that the J-A model is more accurate in describing the magnetic properties of Nd-Fe-B.The working performance of recoil brake under different working temperatures and chamber pressures is calculated,and the demagnetization characteristics of Nd-Fe-B and the damping characteristics of recoil brake under the temperature field are analyzed.The results show that the maximum demagnetization of Nd-Fe-B is 0.351 T under the worst working conditions,and the maximum recoil displacement of recoil brake is 1 108 mm,which provides a theoretical reference for the design of eddy current recoil brake.
gun eddy current recoilbrakeNd-Fe-Bmicromagnetic theorydemagnetization characteris-tic
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