Numerical Analysis And Structural Optimization Design Of Composite Ship Plate Structure Under Different Load

With the rapid development of composite materials,countries have gradually realized the many benefits of applying composite materials to ship equipment manufacturing.The laminates and stiffened plate structure have very important research significance as the basic structural unit of the ship.The bulkhead structure composed of plate or stiffened plate is not only subjected to the excitation of the ship's power devices such as engines,but also the shock wave load generated by torpedoes and other missile explosions at any time.The two different loads have evaluated the vibration response characteristics and shock response characteristics of the structure.Analyzing the vibration and shock resistance characteristics of the structure.Then a reasonable structural optimization design is proposed based on the analysis results of these two aspects,so that the structure has both good vibration resistance and shock resistance simultaneously,which is helpful to ensure the safety of shipboard personnel and improve the ship.The service life of the device has a certain meaning.In summary,this article is based on two basic unit structures of ships,which are different from the various alloy materials commonly used in traditional ships.The structural materials choose more promising composite materials,and the following researches are carried out:(1)Aiming at the analysis of structural vibration characteristics under low-frequency load.Based on the first-order shear deformation theory,the vibration characteristics analysis model of composite(stiffened)laminates under different boundary conditions are constructed through the combination of improved Fourier series method and Rayleigh-Ritz method.Moreover,any boundary conditions of the structure can be simulated by placing artificial virtual springs on the structure boundary.This method has a high level of computational efficiency and accuracy.Then,dynamic properties and sensitivity of the structural parameters of the two types of structures are analyzed.It is found that for the laminated board,the different laying methods of laminate have a greater impact on the vibration resistance of the structure,and the number and layout of stiffeners of the stiffened have a greater impact on the vibration resistance of the structure.(2)Focuses on the dynamic response of the structure under the impact load of underwater explosion.Based on the acoustic-structure coupling algorithm,the impact analysis model of the composite laminate and stiffened plate structure is established,and the impact environment assessment concept is introduced,the impact environment severity and structural deformation deflection are applied to measure the impact resistance of the structure.The influence of different calculation conditions such as calculation time is discussed on the results of explosion shock response.From the material parameters and structural parameters of the laminated plate structure,the different stiffener quantity and different distribution methods in the stiffened plate structure,the impact sensitivity analysis is carried out,The impact sensitivity analysis results of each parameter are obtained,which provides a reference for the structure optimization in the following.(3)Aiming at the optimization design problem of composite structure.Combining the analysis results of the vibration resistance and impact resistance of the composite laminate and stiffened plate structure obtained above,the layering method of the laminate and the layout of the stiffener in the stiffened plate are selected as design variables to established the structure optimization model with objectives of anti-vibration and shock resistance properties.The genetic algorithm is used to screen out the optimal layering method of the fibers in the laminate structure;and the Isight integrated optimization platform is used to optimize the layout of the ribs in the stiffened plate.Moreover,the results through the numerical simulation under optimal parameters are compared with the initial design.It is found that the mechanical properties of the structure have been significantly improved,confirming the feasibility of the structural optimization methodology.