Research On Damage Characteristics Of Ships In Navigational State Subjected To Underwater Explosion

With the continuous development of underwater energy,transportation,and military activities,maritime safety issues have occurred frequently.As the most important combat platform on the sea battlefield,ships have received increasing attention on how to efficiently strike them.Therefore,the research on the damage characteristics of ship structures under the Underwater explosion load is of great significance to the optimization design of maritime operations and the improvement of damage effectiveness of typical weapons.Currently,most studies in this area are based on stationary naval vessels,which may deviate from actual combat situations.This article is based on the aforementioned background and aims to investigate the damage characteristics of large naval vessels in high-speed motion under the influence of underwater explosive loads.The research results can provide a more realistic reflection of the damage incurred by naval vessels under underwater explosive loads,laying the foundation for the design and parameter setting of torpedoes and other underwater weapons to maximize their destructive efficiency during combat.This article first analyzes the fundamental theories involved in the research process.It provides a detailed explanation of the basic principles,governing equations,and contact algorithms of the Arbitrary Lagrangian-Eulerian(ALE)method.Based on the ALE method,a computational model for calculating free-field underwater explosion loads and a numerical model for fluid-structure coupling in the case of underwater explosion on a plate are established.The effectiveness of the ALE method in addressing the structural damage under the influence of underwater explosion loads is validated.Based on the validation of the computational method’s effectiveness,this study investigates the mechanism of structural damage under the influence of underwater explosion loads on moving structures.Firstly,research is conducted on the underwater explosion loads near the boundaries of stationary and moving bodies,providing characteristics of bubble loads near the moving boundary.Secondly,based on the beam theory of the hull,underwater explosion tests are designed and carried out on small equivalent box beams.The characteristics of pulsating bubble loads and their coupling effects with the stationary box beams are determined using numerical methods.Finally,building upon the research on the overall response characteristics of stationary box beams,a numerical model for fluid-structure coupling is established using the ALE method to investigate the variation patterns of the overall response of moving box beams to underwater explosions.Based on this foundation,this study investigates the local and overall damage characteristics of a moving compartment structure under the influence of underwater explosion loads.Firstly,a comparative analysis is conducted on the local damage of stationary and moving compartment structures.The study provides the damage characteristics considering the motion of the compartment structure and analyzes the influence of standoff distance and velocity on the local damage characteristics of the moving compartment structure.Secondly,the overall damage situation of the compartment structure under both stationary and moving states is studied.Based on the quasi-static method,the variation patterns of ultimate strength considering the motion of the compartment structure are obtained,and the effects of standoff distance and velocity on the ultimate strength of the moving compartment structure are analyzed.Finally,an energy-based quantitative analysis is performed to examine the energy absorption patterns of the moving compartment structure when subjected to underwater explosion loads.Finally,the study investigates the local damage characteristics and impact response patterns of a navigating vessel structure under the influence of underwater explosion loads.Firstly,a comparative analysis is conducted on the damage process and local damage characteristics of stationary and navigating vessel structures.The study reveals the unique damage characteristics of the navigating vessel structure considering its motion.Secondly,the impact environment of the entire vessel is examined,providing the variations of the impact environment along the length of the navigating vessel.The study also delves into the changes in the distribution of the impact environment of the entire vessel under different standoff distances and navigating speeds.Lastly,a parametric study is conducted on the damage characteristics of the navigating vessel structure,revealing the influence patterns of standoff distance and navigating speed on the overall vessel damage characteristics.