土壤中碳钢平均腐蚀速度统计特征的分形研究

FRACTAL STUDY ON STATISTICAL CHARACTERISTICS OF AVERAGE CORROSION RATE OF CARBON STEEL IN SOILS

碳钢/土壤腐蚀是一种复杂的随机现象,采用概率统计法不能获得很多这类腐蚀的信息.将这种腐蚀看作分形体系,引入分维修正因子来定量描述腐蚀随机性的复杂程度.通过讨论平均腐蚀速度的统计特性,证实无论平行(重复)试验还是区域土壤腐蚀试验,平均腐蚀速度数据均服从正态分布,并具备分形体系的二个基本特征:稳定分维值和变异系数的自相似性.这些特征值表明,区域土壤腐蚀试验数据的复杂程度要高于平行试验.

Corrosion of carbon steel in soils is very complex and random. The information about this type corrosion could not be obtained completely by traditional methods of the probability and statistics. In the present paper, the corrosion was regarded as a fractal system, and the complexity level of the corrosion was quantitatively described by conception of fractal dimensions. After the statistical characteristics of average corrosion rates were discussed, it was proved that the data of average corrosion rates obeyed normal distribution both from the parallel or repeated tests and from the corrosion tests in local soil region. They had two typical features of fractal systems, namely stable fractal dimension, and the self comparability in variation coefficient of random variable. Based on these features, the complexity level from corrosion tests in local soil region was higher than that from repeated corrosion tests.