电磁轨道炮瞬态电磁场变步长微分求积法研究OA

Numerical simulation of transient electromagnetic fields is a hot issue in the study of launch dynamics of electromagnetic railguns.In order to improve the simulation speed of electromagnetic railgun launching dynamics,for the problem of fast calculation of transient electromagnetic field during the launching process of electromagnetic railgun,the coupled method of finite element and boundary element was adopted to establish the three-dimensional transient electromagnetic field differential-equation.The higher-order differential product time integration method was used to discretise the differential equation in the time domain,and the variable step-size strategy of the circular-frequency-based differential product was put forward,forming the method of finite-element-boundary element-variable step-size differential product time integration transient electromagnetic field analysis.For the classical three-dimensional transient electromagnetic field spatio-temporal evolution problem,comparisons of the calculation results among fixed-step-length,variable-step-length differential product discrete-time method and Euler backward-difference method reveal that the variable-step-length differential product discrete-time method has a higher computational efficiency and computational accuracy.The proposed method and the formed computational model were used for the transient electromagnetic field analysis of the launching process of the electromagnetic railgun.The velocity and displacement of the railgun armature,as well as the current density distribution of the track and armature,and the magnetic field strength distribution were obtained.The validity of the computational model was verified by comparing the results with that obtained from LS-DYNA.The finite element boundary element-variable step size differential product time-integrated transient electromagnetic field analysis method provides an efficient solution strategy for the analysis of electromagnetic railgun launch dynamics.