Applicability of Conventional Ballistic Limit Equation to Titanium Alloy Curved Plate and Energy Distribution of the Fragments after Perforation

抄録

An explosion of a pressure vessel is a cause of debris generation. Debris perforation is considered as a prerequisite to the break-up of the tank. Therefore, the ballistic limit of a tanks wall is an important criterion for debris impact risk assessment. The purpose of this study is to clarify the applicability of the conventional ballistic limit equation for a flat plate to a curved plate and to obtain the energy distribution of the fragments after perforation. Hypervelocity impact tests were conducted on flat and curved titanium alloy plates. Aluminium spheres with a diameter of 0.5 and 1.0 mm impacted the targets at 3-7 km/s in impact velocity. As a result, it was found that the ballistic limit equation for flat plates is applicable to titanium alloy curved plates of 200 mm in curvature radius. Craters on the witness plates placed behind the plates were examined with a digital microscope. The witness plates behind curved plates had fewer craters than behind flat plates. The crater distribution shows that the spray angle of the fragment cloud seems to become smaller due to the target curvature.