The effects of superstructure form on damage characteristics of ship subjected to underwater explosion

To investigate the influence of superstructure on the damage characteristics of ships subjected to a near field underwater explosion, two hull girder models with different superstructures were designed basing on the principle of similarity. The experiment and numerical simulation were conducted to attain the dynamic response of the models. In addition, this paper discussed the impact of the structure and layout modifications of the superstructure on the hull girder's damage and simply analyzed the overall and local coupling damage characteristics of the hull. The results show that the presented numerical simulation could accurately predict the hull girder's overall damage mode and deformation. Under the same explosion condition, the presence of the superstructure increases the hull girder's resistance to the overall bending deformation and minimizes the damage of grillage at the hull bottom. When the abrupt change of cross-section location is within the range of 1/10 girder length from the girder's midspan (to the bow or stern), the failure mode of the hull girder is sagging damage. The length of the superstructure of the hull girder should be limited to 0.4-0.8 times the hull's length; hence, the superstructure and the main hull can resist bending deformation more effectively.