Study On Simplified Model Of Ship Structure Underwater Explosion Resistance Analysis

With the constant improvement of international naval combating capability,it is imperative to enhance the overall strength of Chinese Navy.From the destroyer to the aircraft carrier,the structure of the surface combatant is becoming more and more complicated,and the simulation of the surface ship subjected to underwater explosion takes a lot of manpower and material resources because of the finite element modeling and calculation,but there is only influence on the hull local structure in some experiments,so it is becoming more and more important to find a simple alternative model to replace the whole ship model for local structural response analysis.The setting of the boundary condition of the cabin segment truncation will directly affect the accuracy of the simulation results when the whole ship model is replaced by the cabin which is under high response.However,there is little research on the influence of the setting of the boundary condition of the cabin segment truncation under the underwater explosion.In this paper,we will set the boundary conditions of bulkhead of single cabin and three compartment structure which is nearest to the source of underwater explosion to find the appropriate setting method to improve the accuracy of the simulation results.Based on the main scale,for the convenience of rapid modeling of ships to underwater explosion simulation,summarized the typical structure of surface vessel in the first part of the paper.Through the comparison of the results of finite element analysis and the experimental results to prove the feasibility of the method.Based on the experiment condition,setting the free boundary unconstrained condition to the bulkhead of cabin segment truncation at the first of the second part.Simulating the far-field underwater explosion to prove the feasibility of simplified model replace the whole ship.Then analyze the dynamic response of the impact structure to underwater explosion,when the single cabin and three compartment section obtain with various kinds of fixed methods.Based on the flat section hypothesis and MPC method,coupling the bulkhead ofcabin segment truncation with the beam which replace the non-inspection cabin to build the beam-cabin-beam structure.Simulate the Non-contact underwater explosion in far field after a feasible analysis of the structure,analysis the structure response of the whole ship model and the simplified model.Finally,optimize the non-target cabin with the mass polycondensation principle.Establish the concentrated mass stiffness method for non-target cabin by applying concentrated mass stiffness to the bulkhead of cabin segment truncation.Analyze the equivalent plastic strain and the deflection variation of the inspection area which is built by the concentrated mass stiffness method.