Optimization And Mechanical Properties Analysis Of The Main Frame Of Marine Pipe And Cable Fatigue Testing Machine

With the proposal of our country’s“ocean power”strategy,the independent research and development of supporting equipment required for marine energy development has become more and more important.For marine pipe cables required for marine development,fatigue mechanical properties testing needs to be carried out on a dynamic fatigue testing machine before leaving the factory.However,the design of the marine pipe and cable fatigue testing machine is complex,the manufacturing cost is high,and the design of the main frame of the existing testing machine is more conservative,which has caused material waste in some areas where there is no force.In order to better advance into the deep-sea field,this paper adopts the New Implementation of Asymptotic Homogenization method to quickly optimize the design of the main frame of the marine pipe and cable fatigue testing machine in a certain design,which provides a scientific basis for the design of the fatigue testing machine and has important theoretical value and engineering significance for the detection and use of marine pipe and cable.In this paper,the Asymptotic Homogenization method is used to design the unit cell configuration and selection layout of different main frame structures,and the single-target and multi-target optimization methods are used to optimize the unit cell structure of the main frame and the substructure of the main frame,and the mechanical properties of the optimized overall structure of the main frame are analyzed.The main research work is as follows:（1）The configuration selection and layout design of the unit cell structure of the main frame.Using the New Implementation of Asymptotic Homogenization method,6 different forms of unit cell configurations were established,and the unit cell configurations were determined by analyzing the law of the equivalent elastic modulus E^Hand the number of members..Through finite element analysis of the precise model and the equivalent model,the comparison results verify the correctness of the progressive homogenization method.On this basis,the selection and layout design of the unit cell configuration is carried out.（2）Research on the single-target optimization design of the cross-section size of the unit cell member of the main frame.For unit cell rods with rectangular cross-sections,a single-objective optimization method is used to optimize the design based on the structural strain energy and the equivalent elastic modulus component E₁₁as the objective function,and the structural sensitivity information is given to determine the correctness of the optimization direction,and the two optimization results are considered comprehensively to determine the final configuration of the main frame,and compared with the unoptimized configuration to prove the feasibility and effectiveness of the optimization method.（3）Research on the multi-objective optimization design of the cross-section size of the substructure of the main frame.For H-shaped rods with a cross-section,a multi-objective optimization method is used,taking the minimum mass and minimum total deformation of the three-dimensional substructure,as well as the minimum total deformation and the maximum fundamental frequency as the objective functions,and the response surface optimization method is used to optimize the cross-section size of the substructure members.Design,consider the strong and weak axes of the H-shaped steel,re-arrange it rationally,and determine the final main frame substructure model.By comparing the results of static analysis with the initial scheme,it is proved that the optimized design scheme is reasonable.（4）In view of the overall research of the main frame after the optimized design,the finite element method is used to analyze the stability performance,dynamic performance and fatigue performance of the optimized main frame.Through analysis,the mechanical properties of the main frame of the dynamic fatigue testing machine can be fully verified.The research results of this paper provide a certain research method for the design and actual construction of marine pipe and cable dynamic fatigue testing machine,which has a certain guiding effect and reference value.