| In high-tech combat,the electromagnetic railgun is a new concept weapon that uses electromagnetic acceleration technology to launch high-speed projectiles.Because of its high initial velocity,long-range,easy operation during the launch process,low launch cost,and excellent covert performance,the railgun has broad application prospects in the military field.The launch performance of the electromagnetic railgun will be affected by many factors such as excitation current,armature,and track shape.Based on the launch process of the electromagnetic railgun,the armature,load circuit,and track structure size are studied as the research objects.In this paper,the electromagnetic emission characteristics under different electromagnetic loads and track structure conditions are studied as follows:The C-shaped armature is designed according to the "Marshall’s law".The mechanical pre-tightened force between the armature and the track is calculated by ANSYS LS-DYNA finite element software and the calculation results meet the structural design requirements of the electromagnetic railgun.Under dynamic conditions,the force of the armature is theoretically deduced by the principle of conservation of energy,and the theoretical calculation model of the force of the armature is obtained.According to the load situation of the electromagnetic railgun system,the equivalent circuit of the electromagnetic railgun load is established.Analyzing the characteristics of several calculation methods of inductance gradient and considering the limitations of these methods,the inductance values of the track are obtained by the Maxwell eddy current field solver when the armature is at different positions in this paper.The inductance gradient of the plane track,concave track,and the convex track is obtained by the interpolation method.The initial values of the electromagnetic railgun system parameters are determined according to the structure size and material properties of the armature and track.The current excitation curve of the electromagnetic railgun is obtained by Simulink software.On the premise of releasing the same electric energy,the Maxwell transient field solver is used to simulate the electromagnetic field of the electromagnetic railgun for the current excitation of three different waveforms.Analyzing the difference between the magnetic induction intensity and current density distribution on the armature and the track,the results show that the trapezoidal current excitation is more suitable for the launch of the electromagnetic railgun.Comparing the difference of magnetic induction intensity and current density on the armature with different cross-sectional shapes and the track,the results show that the structure of the convex track and the concave armature is more conducive to the launch of the electromagnetic railgun.The simulation results of the electromagnetic force on the armature are obtained by using Maxwell transient field solver,which verifies the correctness of the theoretical calculation model and provides a certain reference value for the further research of the electromagnetic railgun launch characteristics. |
