The permanent magnets will be irreversibly demagnetized under high temperature and high velocity during the electromagnetic buffering. In this study, the magnetic field induced by eddy currents and the self-demagnetizing field of permanent magnet are taken into consideration together for demagnetization analyse. The magnetic Reynolds number is used to express the eddy currents demagnetization. The correction coefficient being expressed as the index of the air-gap width, the inner cylinder thickness, iron pole axial length and the permanent magnet demagnetization coefficient is introduced by magnetic path analysis to represent the self-demagnetization effect and the demagnetization extent. The electromagnetic buffer (EMB) prototype is tested under intensive impact loads of different strengths at room temperature. The accuracy of the nonlinear irreversible demagnetization finite element model is verified by demagnetization on damping force, velocity and displacement. Finally, high-velocity demagnetization and high-temperature demagnetization are analysed in order to obtain the distribution law of irreversible demagnetization.

在电磁缓冲过程中，永磁体将在高温和高速下不可逆地消磁。在这项研究中，涡流感应出的磁场和永磁体的自退磁场共同被考虑用于退磁分析。磁雷诺数用于表示涡流的去磁。通过磁路分析引入校正系数，该校正系数表示为气隙宽度，内筒厚度，铁极轴向长度和永磁体退磁系数的指标，以表示自退磁效果和退磁程度。电磁缓冲器（EMB）原型在室温下在不同强度的强烈冲击载荷下进行了测试。通过对阻尼力，速度和位移进行消磁，验证了非线性不可逆消磁有限元模型的准确性。最后，对高速退磁和高温退磁进行了分析，以求得不可逆退磁的分布规律。