Experimental investigation into scaling laws for conical shells struck by projectiles

An experimental investigation is reported into the scaling laws for fully clamped thin-walled mild steel conical shells struck axially by plane-head cylindrical projectiles travelling at velocities between 29.5 and 54 m/s. The test shells and projectiles have scale factors of 1, 2 and 4. Some tests are conducted to determine the critical impact velocities to cause cracking or perforation. The other tests are conducted with impact energies which produce dynamic plastic buckling without any rupture or cracking. The critical velocities and the permanent axial deflections of the shells do not obey the elementary geometrically similar scaling laws. The larger deviations are related with the higher impact velocities and larger scale factors. The material strain rate sensitivity effects may be the main factor causing the deviations. The other factor is the localization of the deformation during dynamic plastic buckling.