Development of Optimization System of Cathodic Protection for a Long Buried Structure by Boundory Element Method

在边界元法的基础上，发展了一种新的正分析方法、优化方法和反分析方法，构建了一个长埋地结构阴极保护优化系统。科普长结构埋于非均匀电导率土壤中的情况，引入了电导率线性变化场的基本解。另一方面，研究了快速多极边界元法在腐蚀问题中的应用。本文首先介绍了阴极保护系统中最佳电极位置和最佳外加电流的确定方法，然后将其归结为在保证阴极保护电流的前提下，最小化阴极保护系统的供电量，最大化阴极保护系统的供电量，最大化阴极保护系统的供电量 ...更多信息 罚函数法所考虑的条件。应用该方法对埋在非均匀土壤中的长输管道进行了电极位置和外加电流的优化计算。在优化过程中，采用了多区域法，并采用了适合电导率线性变化的基本解。通过引入惩罚函数，考虑了保护条件，提出了一种提高极化曲线测量精度的方法。该方法采用边界元反分析法消除了电流分布不均匀引起的误差，适用于任意形状的试件，不受参比电极位置的限制。此外，边界元分析的反问题，其中的电流密度通过金属表面的表面估计从测量的电位值在一些点远离金属表面进行了讨论。所得的边界元方程组是病态的，用常规的正则化方法不能得到合理的解。提出了一种利用模糊先验信息求解这类不适定反问题的方法。少

An optimization system of the cathodic protection for a long buried structure was constructed by developing a new direct analysis method, optimization method and inverse method based on the boundary element method.At first, a new boundary element direct analysis method for the galvanic corrosion of a long underground structure was developed. To cope with the case where a long structure was buried in soil with non-uniform electric conductivity, the fundamental solution for a field with linear change of conductivity was introduced. On the other hand, an application of the fast multipole boundary element method to corrosion problems was studied. It was found that this method can be usefully used for large scale corrosion problems.Then, the research to determine the optimum locations of electrodes and the optimum impressed current to each electrode in a cathodic protection system was reviewed, It was found that the problem was reduced to minimizing the power supply under the protecting con … More dition which was taken into account by the penalty function method. Following this method, an optimization of the locations and impressed currents of electrodes for a long pipeline buried in soil with non-uniform electric conductivity was performed. In the optimization, the multi-region method was applied, and the fundamental solution suitable to the linear change of the electric conductivity was used. The protection condition was taken into account by introducing the penalty function.Finally, a method for improving the accuracy of measuring polarization curves was proposed. In this method, a boundary element inverse analysis method was employed to eliminate the error due to the nonuniform current distribution, The method is applicable to an arbitrarily shaped specimen without any restriction of the location of a reference electrode. Furthermore, a boundary element analysis of an inverse problem in which the density of current across the surface of the metal surfaces is estimated from the measured potential values at some points far from the metal surfaces was discussed. The system of boundary element equations obtained was so ill-conditioned that a reasonable solution could not be obtained by the conventional regularization methods. A method using fuzzy a priori informations was proposed for solving this kind of ill-posed inverse problem. Less