Objectives  Deflecting an incoming projectile using electromagnetic force on the projectile body between polar plates is a creative protection method for weapons and equipment. In order to study the adaptability of the wire current theory and the influence factor of the deflecting electromagnetic force,

  Methods   the wire current theory of electromagnetic force is established and a simplified model and 3D model simulated on the basis of the finite element method. Using changing simulation parameters and a fitting method, the electromagnetic force variation is then studied under the influence of such factors as the geometric parameters of the plates, impact location and penetration angle of projectile.

  Results   The obtained results are as follows:the deflecting electromagnetic force in the 3D simulation is only 1/7 that of the wire current model, so the wire current theory is not suitable for the 3D design of passive electromagnetic armor; the electromagnetic force decreases with the width of the plates in accordance with the power function law; the lateral deflecting electromagnetic force has a quadratic function with the impact location in the transverse and lateral directions; and the penetration angle has little impact on the lateral deflecting electromagnetic force.

  Conclusions   The results of this paper can provide a foundation for the mechanism experiments, conceptual design and ship application of passive electromagnetic armor.