This paper aims to study the penetration of graded one-, two-, three- and four-layered Weldox 460 E steel plates in the same total thickness of 12mm by hemispherical-nosed cylindrical projectiles numerically. The circular targets of Weldox 460 E having a diameter of 500 mm and the hemispherical-nosed projectiles are machined Arne tool steel cylinders with a mass of 0.197 kg hardened to 53RC. The multi-layered targets are simulated as the layers are in-contact and no gap was assumed between them. Tests are carried out using LS-DYNA finite element code. According to the ballistic limit velocities determination, the effect of multi-layering target and grading the layers on the ballistic limit velocity for 12mm thickness target are investigated. Results illustrate that in the number of layers increase, targets have lower ballistic limit velocities in in-contact situation with the same total thickness of 12mm. Furthermore, multi-layering targets cause lower ballistic limit velocities; however, between multi-layered targets, grading the thickness of layers and ordering them from the lower to the higher thickness mostly causes higher ballistic limit velocity but only one exception was observed.
