Review of the Adhesively Bonded Interface in a Solid Rocket Motor

One of the most challenging requirements in a solid rocket motor (SRM) is the integrity of the charge structure which is a multilayer adhesive joint involving the propellant, liner, and insulation. The propellant/liner/insulation interface is considered to be the weakest part of the whole structure. This interface has some of the usual features of an adhesively bonded interface, as well as its own special characteristics: the co-cured process, ingredient migration between interfaces, and complicated damage mechanisms. We give a technical and critical review of the past 50 years of existing research on many aspects of the propellant/liner/insulation interface in terms of the adhesive properties and adhesive mechanisms, ingredients migration, damage determination, and fracture analysis. To present a comprehensive outline of this interface we also clarify some remaining problems which should be addressed in the future. With significant improvements in the theoretical and experimental studies of the propellant/liner/insulation interface, the problem of integrity failure of the charge structure in SRM will be well resolved.