Study On Structural Mechanics Properties Of Deep Sea Profile Floats And Its Multi-Objective Optimization

With the development of science and technology,the scope of human exploration has gradually extended from land to the ocean.Due to the vast ocean area,geological movements,climate change and ocean circulation in the oceans have a profound impact on the terrestrial environment and human life.At the same time,there are abundant resources in the ocean,the development and utilization of marine resources can greatly alleviate the diminishing situation of traditional resources.In recent years,underwater exploration and deep sea exploration,the development and utilization of marine resources has gradually become a hot topic and research hotspot.A variety of underwater detectors including manned detectors,underwater robots,water gliders,and marine detection floats have been developed and participated in underwater exploration operations.The research object of this paper is the 4000 m deep water profile detection float independently developed by Shandong University.For the large depth detector needs to withstand the deep water high pressure,it also needs to provide enough effective buoyancy.This paper focuses on the research of high pressure cylindrical shell,the mechanical model of high-pressure cylindrical shell is established,and then the finite element simulation analysis is carried out.The multi-objective optimization of shell parameters based on genetic algorithm is used to verify the reliability of the shell by pressure test.Firstly,accept the working principle and main structural components of the deep water profile float.Its structure mainly includes ultra-high pressure small hydraulically driven buoyancy regulation system,multi-parameter sensor system consisting of warm salt and deep dissolved oxygen sensor,real-time positioning and information transparent transmission system integrating comet module and GPS,controlling buoyancy condition system,collecting The sensor collects data,controls the positioning and transmits the embedded system,and can withstand deep sea high pressure and provide positive buoyancy with a pressure-resistant cylindrical housing.Secondly,through the equilibrium equation of cylindrical shell,constitutive equation,deflection equation and deformation coordination equation,combined with the reduction of Donnell,the cylindrical shell equilibrium equation and cylindrical shell coordination equation based on Donnell simplification are derived,and the initial defect coefficient is introduced into it.The triangular series is used to replace the coordinates,and the equilibrium equation and the coordination equation are solved by the energy method Hamiltonian principle.The maximum unsteady analytic function of the cylindrical shell with respect to parameters such as radius,length and wave number is obtained.Then using the finite element analysis software Abaqus,the static analysis of the cylindrical shell under different constraints is carried out,and the stress and strain of different size shells are obtained.At the same time,the eigenvalue buckling analysis of the cylindrical shell under different constraints is carried out and the critical pressure of the shell under linear buckling is obtained.Based on the eigenvalue buckling,the initial defect coefficient is added to the inp.file to simulate the non-linearity of the cylindrical shell.Based on the results of strength analysis and nonlinear buckling analysis,the reinforced ribs were used to optimize and strengthen the shell and compared with finite element analysis.Based on the structural analysis of the shell structure and finite element simulation,the NSGA-? based genetic algorithm was used to optimize the multi-objective parameters of the dimensional parameters and material parameters of the deep water anti-pressure shell.The initial population was established,and the Pareto optimal solution of cylindrical shells of different materials was solved by multi-generation inheritance through crossover,mutation and selection operators.And get the depth range that different materials are suitable for.Finally,based on the theoretical,simulation and algorithm optimization of the optimal size function of the shell,the optimal shell size is selected according to the actual quality of the actual needs,and the pressure test is verified.The assembled buoy was tested on the lake to test the buoyancy regulation system,and then the scientific test was carried out to carry out the sea test to test the actual effect.