Research On Lightweight Design Of Air-controlled Dock Gate

In the past half century,with the development of the global marine industry,the shipbuilding industry has made considerable progress.Ship construction is developing towards large-scale and specialization.As one of the most important places for ship repair,dock is an indispensable facility for large-scale ship assembly and construction.As a key part of dock construction,the performance of dock gate directly affects the overall performance of dock.In this paper,an air-controlled horizontal dock door is selected for optimum design.On the premise of ensuring that the mechanical properties of the dock door structure meet the design specifications,the lightweight design of the dock door is carried out by using the method of structural optimum design.The main contents of this paper are as follows:(1)The structural design principle of pneumatic horizontal dock door is described in detail,and the structural performance evaluation index of pneumatic horizontal dock door is elaborated.The commonly used lightweight structural design methods,such as topology optimization method,size optimization method,shape optimization method and application of new materials method,are introduced,and their research status is described.(2)Static analysis of dock gate structure: The geometric model of dock gate structure is established by CATIA,and the finite element analysis model of dock gate structure is established by Hypermesh.The structural static analysis is carried out for the closing condition of dock gate limit water level and the lying condition of dock gate respectively.The calculation results provide a comparison and reference for the structural optimization of dock doors in the next stage.(3)Dock gate structure layout optimization: The homogenization method,variable density method and SIMP method improved by homogenization method and variable density method in topology optimization theory are elaborated in detail.OptiStruct,a structural topology optimization software based on SIMP method,is introduced,and its optimization process is also introduced.Based on the working principle of the pneumatic horizontal dock door,the area where the strong frame and longitudinal bone are located is chosen as the design optimization area to establish the optimization model.The optimization objective is to minimize the weight of the structure,and the structural deformation and material allowable stress are constrained to carry out the topology optimization.The layout of dock gate structure is adjusted according to the results of topological optimization.(4)Size optimization and topology optimization: Based on the optimized structure of the dock gate,the thickness of the inner and outer plates,strong frames and longitudinal bones of the dock gate structure are taken as optimization variables,and the objective function is to minimize the weight of the structure.On this basis,the strong frame of dock door is selected for topology optimization,and the lightweight design of dock door is further carried out.(5)Structural checking and performance comparison: Static analysis of the optimized dock gate structure is carried out under closed and lying conditions respectively.Structural strength,stiffness and structural stability of dock doors are checked based on design specifications.The performance of the original dock gate structure is compared in terms of displacement,stress and weight.