Abstract: To investigate the stress wave propagation mechanisms within curved shell structures during the separation of curved shell specimens by a ring-shaped detonation cord in an underwater environment, this study combines experimental testing and numerical simulation to systematically investigate the dynamic response of light-cured resin curved shell specimens with integrated skirts subjected to underwater explosion loading. Particular emphasis is placed on elucidating the propagation mechanisms of stress waves within the curved shell when a ring-shaped detonation cord embedded in the skirt is synchronously initiated using multiple initiation points. By comparing the stress wave propagation processes under different initiation configurations, the influence of the initiation mode on stress wave evolution, stress concentration behavior, and the dynamic response of the curved shell is comprehensively analyzed. Numerical simulations are further employed to reveal the transient evolution of the stress field and to clarify the underlying mechanisms governing stress wave propagation and convergence within the curved shell. The results demonstrate that different initiation modes significantly affect the propagation characteristics of stress waves within the curved shell, resulting in the formation of different numbers of stress concentration points. A distinct geometric relationship is observed among the apex of the curved shell, the stress concentration points, and the corresponding convergence points of the detonation waves generated by the ring-shaped detonation cord, all of which are consistently located on the same plane. This finding indicates a strong correlation between the locations of stress concentration and the initiation mode. Furthermore, as the number of initiation points increases, the number of stress concentration points increases correspondingly, whereas the peak stress at these locations decreases significantly. These findings provide a deeper understanding of stress wave propagation and stress concentration mechanisms in curved shell structures subjected to underwater explosion loading and offer valuable guidance for the design of explosive initiation networks for underwater blast-resistant structures and underwater separation devices with similar structural configurations.