Analysis of the fracture of gas-filled pressure vessels under hypervelocity impact

Abstract

The first part of the study summarizes the results of hypervelocity impact tests on unshielded thin-walled cylindrical pressure vessels made of aluminium alloy. Impact damages ranged from simple front wall perforation with no further damages inside the vessel to catastrophic bursting into many pieces. Two types of catastrophic bursting were observed: front side and rear side failure. Front side failure was initiated at the rim of the front side impact hole. The second part of the study analyzes the physical mechanisms that are involved in the hypervelocity impact process on pressure vessels and simulates the experimental results presented in the first part. In order to treat this problem, the fragment cloud that was generated from the front side impact was assumed to be completely ablated and decelerated in the gas, which is in correspondance with experimental observations for pressures exceeding a few atmospheres. In the presented model the impact event was divided in different stages, that are treated separately. These are: perforation of the front wall and generation of a strong gas shock wave, propagation and damping of the gas shock wave, impact of the gas shock wave on the rear wall and reflection thereof, propagation of the gas shock wave to the front side and interaction with it. Models for the treatment of front and rear side failure mechanisms are presented. The validity of the presented analysis was proven by simulation of the experimental results obtained in the first part of the paper.