Objectives  This paper aims to analyze the protective performance of different broadside protection structures subjected to semi-armor-piercing missile warheads.

  Methods  Single-layer homogeneous steel armor structures and double-grid protection structures are designed, and the protective performance of different broadside protection structures in blocking medium subsonic semi-armor-piercing missile warheads is compared via numerical simulation.

  Results  The results show that it is easy to design single-layer homogenous steel armor for use as broadside protection structure, but high strength steel with excellent mechanical properties should be used and the thickness should be more than 50 mm. In addition, consideration should be given to the construction of thin plates and thick plates, as well as the electrochemical corrosion of different types of steel. The above problems can be avoided by using a double-layer structure as the broadside protection structure. For double-grid protection structures, the weight resources should be allocated to the inner plate by increasing its thickness, thereby improving the overall protective ability of the double-grid protection structure.

  Conclusions   The results of this study can provide useful references for the design of broadside protection structures capable of withstanding semi-armor-piercing missile warheads.