Investigation on structural failure of filament reinforced barrel containment

During the launching process of a composite railgun, some working conditions may lead to the structure failure of its filament reinforced barrel. For instance, the instantaneous electric power impact caused by the unexpected large pulse current and surge from the pulse-forming network, which inspires the electrodynamic response beyond the safety limit of the barrel. More importantly, the alternating load after a long-term working causes damage accumulation and failure in the composite structure. For the railgun, considering that the radial deformation of the barrel has special effect on the contact state of the rail and armature in bore, it is necessary to focus on whether the radial stiffness of the barrel is affected even if the strength of the barrel does not decrease significantly by hidden injuries in the fiber wraps. In this study, based on the common used method of progressive failure theory, the radial stiffness attenuation process of the barrel is analyzed. The fiber fracture and composite delamination failure modes are found to be the main factors for radial stiffness attenuation of railgun barrel containment as persistent deformation will generate after these damage propagation. In addition, the loss of prestress in the fiber containment is evaluated based on structural analysis for the barrel in service and in manufacturing time. The research has found that optimized preloading seems important for improving the strength performance of the barrel.