13th International Conference on Fracture June 16–21, 2013, Beijing, China -7- It is evident from Fig.2 to Fig.5 that the simulation results are in good agreement with the experimental results, and the finite element model is reliable. Based on the present FE model, perforation of 6mm thick Weldox460E steel plates struck normally by rigid conical-nosed projectiles with various cone angles will be analyzed in the following section. 3. Numerical simulations for conical-nosed projectiles with various cone angles In this section, the perforation behaviors of 6mm thick Weldox460E steel plates under normal impact by conical-nosed projectiles with cone angle θ=20 o、60o、100o and 140o are analyzed by numerical simulations. The projectiles with various cone angles have the same effective length eff L , 2 4 eff t L M d , the diameter (d) and the mass (M) of which are 20mm and 197g, respectively. Thus, the total lengths of projectiles with θ=20 o、60o、100o and 140o are 111.2mm, 88.9mm, 83.9mm and 81.2mm, respectively. The strike velocities of the projectiles are 200 m/s. Fig.6 shows the perforation process of 6mm thick Weldox460E steel plate under normal impact by conical-nosed projectile with θ=20o through numerical simulation. It can be seen clearly from Fig.6 that the materials accumulated aside the perforation hole is formed by radial expansion. Thus, it is deduced that the dominant failure mode here is ductile hole enlargement with global deformation. Figure 6. The perforation process of 6mm thick Weldox460E steel plate under normal impact by projectile with θ=20o through numerical simulation. Fig.7 shows the perforation process of 6mm thick Weldox460E steel plate under normal impact by conical-nosed projectile with θ=60o through numerical simulation. It can be seen clearly from Fig.7 that local bending occurs for the materials beside the projectile, and the dominant failure mode is classified to petalling with global deformation.
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