Static and dynamic penetration of steel tubes by hemispherically nosed punches

An experimental investigation into the quasi-static and dynamic local loading of steel tubes has been carried out. Emphasis is placed on the energy absorption properties of the tubes when subjected to inward radial penetration from a hemispherically tipped indenter and to impact from hemispherically tipped projectiles travelling at velocities close to the ballistic limit of the target tube. The ballistic limit provides the most sensitive measure of a target's ability to resist impact. The tubes tested all had diameter to wall thickness (D/t) ratios of 31 and the punch/projectile diameter to tube diameter ratio was kept constant at a value of 0.125. Two types of steel tube were used in the tests: cold drawn mild steel tubes with outside diameters of 51, 102 and 153 mm and rolled tubes with a welded seam with outside diameters of 51 mm. The effects of projectile mass, projectile nose radius and the means of target support on the energy required for perforation of the tube wall were investigated as was the effect of the difference in the type of loading, static or dynamic.