Research On Numerical Simulation And Optimization Design Of Anti-Corrosion Systems In Ocean Engineering

Large-scale ocean structures used for deep-sea resource development generally require to ensure adequate security in a long period, and the method of anti-corrosion coating with cathodic protection is widely used. It's the question people pay more and more attention to that how to design the cathodic protection system properly. The application of numerical simulation techniques in the corrosion field can greatly give an impulse to the application and development of cathodic protection, and promote the progress of marine corrosion control technology. Aiming at the numerical optimization design technology of anti-corrosion systems in complex marine structures, some key issues are researched in this paper based on the technology of BEM numerical simulation. The main work and results obtained from the researches of this paper are summarized as follows:(1) Research of the parallel computing technology. According to the BEM grid convergence analysis, the accuracy of a numerical result relates to the meshing density. The "Numerical Simulation Software of Ocean Engineering's Anti-corrosion System" based on single computer will not be able to achieve a reliable simulation for large-scale ocean engineering's anti-corrosion system. In view of this, the corresponding parallel computation technique is established. The SMP and Cluster parallel computers are set up, the parallel computation of "Numerical Simulation Software of Ocean Engineering's Anti-corrosion System" is firstly achieved. The parallel performance test results show that the program has a high parallel efficiency, which firstly established the solutions of numerical simulation for large-scale ocean engineering's anti-corrosion system.(2) Optimization technology of anti-corrosion systems in ocean engineering. A sensitivity analysis of anti-corrosion design parameters is carried out by the numerical simulation system. The optimization model of anode location and anode output current are presented. In order to raise the solving efficiency, the optimization method based on initial design is proposed. This method only selects the design parameters which are fit for readjustment and have great influence to the cathodic protection effect as the optimization variables, so that the scale of the problem can be reduced as much as possible. This paper use BP neural network to establish the non-linear mapping of the design variables with the mean protection potential and potential variance, and then use the iterative search method to find the optimal solution. The optimization design for a semi-submersible platform's ICCP systems have showed the rationality and validity of the optimization method.(3) Development of the integrated software system. For the common coupling system of SACP systems, ICCP systems, complex galvanic couple systems and stray current corrosion system of ocean engineering structures, the corresponding integrated numerical simulation and optimization software system is developed. A complete pre-treatment and post-processing module, database management module, and three-dimensional visualization module are formed in this system. The development of the integrated software system established an important foundation of the promoting for "Numerical Simulation Software of Ocean Engineering's Anti-corrosion System".