Research Of Random Field Model For Assessment Of Ultimate Strength With Corrosion

In the ocean environment, ultimate strength of ships and marine structures decreases because of the increasing corrosion when they are in service. Therefore, the assessment of ultimate strength for ships and marine structures with corrosion becomes very important to judge the safety of them. However, it is simple and not accurate to consider the real surface of the ships and marine structures as uniform corrosion when the real surface is not consistent.This paper presents a study about the assessment of ultimate strength of ship and marine structures with corrosion, particularly the ultimate strength development of structures with random fields corrosion. It provides a reasonable basis for the assessment of ultimate strength of ships and marine structures with non-uniform corrosion. The main contents of this paper are as follows:(1) Describing the establishment of plates with random fields corrosion. Through the selection of model size, initial imperfection, element type, the size of element, corrosion data, the method for realization of random fields corrosion, we establish of plates with random fields corrosion for finite element analysis to calculate the ultimate strength of them.(2) With the uniaxial compressive load, the analysis for the effect of aspect ratios and initial slenderness on the degradation of ultimate strength is presented. Through large calculation of ultimate strength and degradation of it, we can find the difference of degradation of ultimate strength between random fields corrosion model and uniform corrosion model which should not be neglected and the formulas of the ultimate strength degradation of random fields corrosion plate.(3) With the biaxial compressive load, the analysis for the effect of load ratios and initial slenderness on the degradation of ultimate strength is presented. Through large calculation of ultimate strength and degradation of it, we can find the difference of degradation of ultimate strength between random fields corrosion model and uniform corrosion model which should not be neglected and the formulas of the ultimate strength degradation of random fields corrosion plate.Through the study of this paper, we can obtain the method for assessment of ultimate strength for ships and marine structures which is much more accurate than traditional assessment which consider the real surface of the ships and marine structures as uniform corrosion when the real surface is not consistent.