Rupture characteristics of composite overwrapped pressure vessels under hypervelocity impact

With the increasing frequency of human space activities, the orbital debris environment continues to deteriorate, posing a significant threat to spacecraft and their components. As critical energy-containing components, Composite overwrapped pressure vessels (COPVs) are widely used in spacecraft due to their superior strength-to-weight ratio, making their damage behavior under hypervelocity impact particularly crucial. Employing experimental analysis, this study systematically investigates the most severe failure of COPVs under hypervelocity impact: catastrophic rupture. Firstly, hypervelocity impact tests were conducted using a two-stage light gas gun to obtain the damage modes of different types of COPVs under various impact and internal pressure conditions, including two categories: simple perforation and catastrophic rupture. Through traceability analysis of the fragments, the distribution and types of cracks after rupture were clarified, and typical damage morphologies such as axial cracks were identified. Secondly, by combining the pre-impact stress state of the COPV wall under internal pressurization with the dynamic damage process induced by the impact, the rupture mechanism was revealed: cracks initiate from impact-induced perforations or inherent structural defects and undergo unstable propagation along the path of least resistance driven by the pre-existing stress field within the wall, ultimately leading to the catastrophic rupture of the vessel. Furthermore, inspired by fracture mechanics concepts and calibrated against experimental data, an empirical front-wall rupture limit equation for COPVs was proposed, establishing a quantitative relationship between the rupture condition and factors such as impact parameters, internal pressure, and wall thickness. The results indicate that internal pressure and composite layer thickness have the most significant influence on front-wall rupture, while impact velocity plays a comparatively minor role within the studied range. The rupture limit equation proposed in this work provides a theoretical basis and methodological reference for the engineering safety assessment and protective design of COPVs under hypervelocity impact.