Analysis of edge stress of combined shell under internal waves

Internal wave is essentially a gravity wave induced by the layered structure of water (e.g., density stable layering), with its maximum amplitude occurring within the ocean. Similar to surface waves, internal waves have significant influence on the strength and stability of a submerged body as an external factor. Meanwhile, combined shells are exposed to complicated loads under internal waves, and edge stress is dominant. In this study, the edge stresses of combined shell (typical hemisphere–cylinder combined shell and unfolded sphere–cylinder combined shell) under internal waves were analyzed. Indeed, a semi-empirical, semi-theoretical formula for the edge stress of combined shells (typical hemisphere–cylinder combined shell and unfolded sphere–cylinder combined shell) has been proposed. In this study, the semi-empirical, semi-theoretical formula was corrected by introducing internal wave loads, with the depth of the internal wave taken into consideration. In addition, the corrected formula was verified by finite element analysis, and a simplified equation for the calculation of edge stress of the combined shell under internal waves was developed, with errors in a rational range.