1994 Fiscal Year Final Research Report Summary
DEVELOPMENT OF AN EVALUATION METHOD FOR THE POTENTIAL DISTRIBUTION IN OFFSHORE STRUCTURES UNDER CATHODIC PROTECTION
| Project/Area Number |
05555272
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
海洋工学
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
IWATA Mitsumasa GRADUATE SCHOOL,INTERNATIONAL DEVELOPMENT AND COOPERATION,Hiroshima University, 大学院・国際協力研究科, 教授 (80034346)
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| Co-Investigator(Kenkyū-buntansha) |
HUANG Yi FACULTY OF ENGINEERING,RESEARCH ASSOCIATE, 工学部, 助手 (20253114)
FUJIMOTO Yukio FACULTY OF ENGINEERING,PROFESSOR, 工学部, 教授 (60136140)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Boundary element method / Plane isoparametric element / Green's function / Cylindrical surface element / Cathodic protection / Piecewise uniform domain / Life-span of anode |
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| Research Abstract |
In this research, an evaluation system for the potential distribution in offshore structures under cathodic protection was developed based on the boundary element method (BEM).
In order to discretize any complex 3-D curved surfaces such as ship hull surface and tubular offshore jacket and platform structure surface accurately and efficiently, two types of plane isoparametric elements : plane triangular linear element, plane rectangular bilinear element, and three types of cylindrical surface isoparametric elements : cylindrical linear element, cylindrical surface trapezoidal bilinear element and cylindrical surface triangular linear element were developed.
Moreover, in the calculation model of the cathodic protection problem of offshore structures, such as harbor pile and oil jacket, the ununiform electrolyte domain consisting of sea water and sea bottom mud is simplified to two uniform subregions divided by the watermud interface. Based on this simplification, discretization of the interface between two subregions in the BEM analysis is avoided by using an adequate Green's function.
As application examples of the proposed evaluation system, cathodic protection systems of a steel quay constructed by driving a steel sheet into ocean bottom mud, a harbor structure by driving steel piles into ocean bottom mud and ballast tank were investigated.
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