Key Technology Of Design & Analysis For Deepsea ROV And Hybrid Structures

The mechanical analysis technologies involved in the design of pressured electric cabin for deepwater ROV are investigated. Finite element method is employed to verify the strength, stiffness and stability of pressured electric cabin. According to the surrounding load conditions, the topology and the sizes of the cabin are optimized and the optimal topology configuration is obtained. To investigate the contact mechanism of the joint surface between the upper and lower part of pressured electric cabin, the computation results are compared between nonlinear contact analysis and simplified analysis. In addition, the impact of mismachining tolerance and initial imperfection on the mechanical performance are discussed too. Computation results showed that the final design scheme satisfied the requirements on the mechanical properties and weight, and the mechanical properties are insensitive to the mismachining tolerance and the initial imperfection. Similarly, finite element method is employed to verify the strength, stiffness of ROV framework under retrieve and fixed condition. Caculation results showed that the design scheme satisfied the operating requirements.Materials selection optimization design for the steel-compostie hybrid structures under dynamics constraints is investigated. The material types (steel and composite material), elastic modules of the materials and structural sizes (thickness of the plate) in the steel-composite hybrid structures are defined as design variables respectively. Different mathematical optimization models with mixed continuous and discrete design variables are established under vibration level difference, stress and displacement constraints. The genetic algorithm is employed to solve the presented optimization problems. Computational results show high effectiveness of materials allocation than that of the common dynamics optimization with size design variables and single material. Because of the non-diiferential difficulties in the materials selection optimization problems, the polish function transformation method is applied for the continuity of the mathematical formulations. The optimization results of the proposed six polish function transformation models are compared with that of the discrete variable optimization model, it showed that Sigmoid polish function, arctan polish function and piecewise polish function are more suitable for the continuity of the mathematical formulations of materials selection optimization model.