| With the extensively use of submarine pipeline, its security become a more and more serious problem. Researches indicate that corrosion is the key reason of pipeline failure. A compound anti-corrosion means by using protection coatings and sacrificial anode jointly is generally used in submarine pipeline corrosion prevention, in order to make sure its safety in a long period, the status of pipeline protection should be exactly described. There are two meanings in submarine pipeline anti-corrosion status, one is the status of cathodic protection of the pipeline surface, and the other is the status of submarine pipeline corrosion protection system.The status of submarine pipe corrosion protection system can be described by the following several parameters:the defection ratio of anti-corrosion coat, the remaining weight of sacrificial anodes, the current of sacrificial anode, the surface of submarine pipe corrosion protection can be described by electric potential, but none of these can be acquired by regular detection devices. When the submarine pipe anti-corrosion system works, it will form an ambient electric field which has a close relationship with status of the system and the environment. But the relationship between these factors is very complex and the status of the ambient electric field under certain factor can only be obtained. Simulation calculation based on boundary element method which is proved to be an effective method. So an "Ambient Electric Field-Influencing Factors Database" is established to reflect the corresponding relationship of the rate of missing areas of pipe coating, the weight of left sacrificial anode, current intensity of cathodic protection, environment factors(polarization characteristics of exposed pipe, sea water resistivity, sea mud resistivity, buried depth of pipeline) with the electric field of submarine pipeline cathodic protection. A large amount of boundary element simulation calculation and analysis are needed in order to fully describe the relationship.Main work and achievement of this paper:(1)Research of parallel and distributed computing.According to the convergence of boundary element simulation, the accuracy of result is related to the size of elements. Traditional serial calculation of submarine pipeline anti-corrosion system cannot realize the large-scale model simulation calculation and are also not qualified for the model designed for the database mentioned by single computer. On condition of parallel and distributed computation, the system is established by combining multi-core computation and network jobs management together which shows high efficiency though test and complete the database. (2)Relativity analysis of parameters of simulation calculationSince the database has been completed, the parameters involved are analyzed to figure out the relationship between "input parameters" and "output parameters" and the nonlinear mapping between the neural network and the model of submarine pipeline cathodic protection system are validate.(3) The establishment of network mapping modelAccording to relativity analysis, two kinds of network mapping models are brought forward combined with engineering practice. Through the training, the relative error of the mapping model is small, which is met the accuracy requirements. |
