A rupture limit equation for COPVs following a perforating MMOD impact

Abstract

Most spacecraft have at least one pressurized vessel on board. One of the primary design considerations for earth-orbiting spacecraft is the anticipation and mitigation of the possible damage that might occur in the event of a micrometeoroid or orbital debris (MMOD) particle impact. To prevent mission failure and possibly loss of life, protection against perforation by such high-speed impacts must be included. In addition to a hole, it is possible that, for certain pressure vessel designs, materials, impact parameters, and operating conditions, a pressure vessel may experience catastrophic failure (i.e. rupture) as a result of a hypervelocity impact. If such a tank rupture were to occur on-orbit following an MMOD impact, not only could it lead to loss of spacecraft, but quite possibly, for human missions, it could also result in loss of life. In this paper we present an update to a Rupture Limit Equation, or RLE, for composite overwrapped pressure vessels (COPVs) that was presented previously. The update consists of modified RLE parameters and coefficients that were obtained after the RLE was re-derived using new / additional data. The updated RLE functions in a manner similar to that of a ballistic limit equation, or BLE, that is, it differentiates between regions of operating and impact conditions that, given a tank wall perforation, would result in either tank rupture or only a relatively small hole or crack. This is an important consideration in the design of a COPV pressurized tank – if possible, design parameters and operating conditions should be chosen such that additional sizable debris (such as that which would be created in the event of tank rupture or catastrophic failure) is not created as a result of an on-orbit MMOD particle impact.