Dynamic Responses Study And Structural Optimization Of Ship Side Collision

Impact load is a kind of extremely dangerous load.The improvement of impact resistance is of great significance to ship.Since the more attention has been paid to the polar channel,the anti-collision and anti-ice performance of the ship is becoming more and more important.Based on the experimental and numerical methods,the dynamic response of simplified structure under the impact of rigid wedge and the impact of ice wedge was studied,and the design proposals for collision resistance were obtained.The structural optimization design of side structure is explored.Simplified structural optimization design,inverse problem of calculating the load according to the deformation and the anti-collision optimization of the local structure of a real ship side were studied.The above researches provide good technical cases.The specific research contents include:1)Based on the assumption of rigid body,the condition of ship side impacted by a ship bow is simplified as a stiffened plate or a bald plate impacted by a spherical or wedge-shaped indenter.Based on numerical calculation and experimental verification,the structural responses and energy absorption of the stiffened plate or the bald plate impacted by two kinds of indenters were analyzed and compared.It is learned that the area which is easy to impacted by the spherical-shaped indenter should be reinforced and the area which is easy to impacted by the wedge-shaped indenter should increase the plate thickness.2)Based on the validated simulation model of ice material,the numerical calculations of the clamped plates impacted by the floating ice model with different forepart widths were implemented.The structural responses were analyzed and the results are compared with the results of the rigid wedge impact case.The Ice Influence Factor on Deflection(IIFD)and the Damage Energy Reduction Ratio(DERR),which are used to characterize the displacement and energy absorption,are presented.It is available that: During the ice impact process,the weak parts of the structure are more likely to suffer from severe damage.Ice ship anti-collision design should consider the overall structure of strength balance,to minimize the occurrence of fragile part.3)The structural optimization design is also implemented for the stiffened plate structures impacted by the spherical wedge.The thickness of outer panel,panel of stiffener and web panel were well optimized.The solution of inverse problem of calculating the load according to the deformation is proposed innovatively: The parameters of impact load are set as independent variables.With the using of Kriging agent model and based on the plastic deformation of structure,the mass and velocity of the impact load were obtained.4)Aiming to solve the condition of ship local structure impacted by the bow-shape structure,self-compile artificial neural network and genetic optimization algorithm were used to optimize the local side structure of 10 design variables.More design variables leads to huge design space and long single solving time leads to high time-consuming.Therefore,the combination method of parameters pre-calculation and experimental design was used to improve the design efficiency and the reliable results were obtained.