Damage characteristics of cabin in navigational state subjected to near-field underwater explosion

Abstract

An arbitrary Lagrange-Euler (ALE) method is used to establish a numerical model for the fluid-structure interaction of near-field underwater explosion while cabins are under sailing conditions. First, the ALE method is used to calculate shock wave and bubble pulsation loads of free field underwater explosion. The results show that the values of shock wave peak, bubble fluctuation period, maximum radius of bubble are similar to empirical formula calculation, which verifies the accuracy of ALE method in calculating explosion loads. On this basis, from the aspects of local damage, longitudinal strength and impact environment of cabin structure, the dynamic response characteristics of cabin structure under the coupling of impact and bubble load at a certain speed and different explosion distance are analyzed and compared with that at static condition. The results show that compared with the static state, the local damage is weakened, the longitudinal strength is increased, the difference of longitudinal strength between navigation and static state is 7%–12%, the shock spectrum value of the compartment corresponding to the explosion source is reduced, and the shock spectrum value of the adjacent compartment is slightly increased; When the cabin is sailing, the increase of the explosion distance within the maximum radius of bubble pulsation increases the action area of bubble pulsation load, and the effect of bubble pulsation load is enhanced, but the coupling enhancement of explosion load is difficult to appear, so that the damage of cabin structure is reduced. The working condition of the cabin suffering from near-field underwater explosion damage under the navigational state analyzed in this paper is closer to the reality, and more truly reflects the process of underwater explosion shock wave and bubble load coupling applied to cabins, which lays a foundation for the fuze warhead coordination design and relevant parameter setting when the torpedo and other underwater weapons give full play to the damage efficiency.