碳钢土壤腐蚀速度波动性表征的研究

Study on Random Fluctuation Characteristics for Corrosion Rate of Carbon Steel in Soils

碳钢土壤腐蚀是复杂的随机现象。按照统计学方法,其腐蚀速度被看作服从正态分布,腐蚀速度的波动性分别用标准偏差或变异系数(CoV)表示。笔者根据大量腐蚀试验数据,将标准偏差分布看作统计分形体系,分别计算了平行腐蚀试验数据和区域腐蚀试验数据的分维,分别为1.343和1.486。通过分形修正提出新的变异系数来描述碳钢土壤腐蚀的随机波动性。此外,当平行试样数量大于6片后分维趋于恒定。新变异系数和腐蚀发生程度无关,是腐蚀速度随机波动特性更好的表征形式。

The corrosion of carbon steel in soils is a complex and random phenomenon. According to the statistics, the corrosion rates follow the normal distribution. Their random fluctuation could be described by the standard deviation and the coefficient of variation (CoV), respectively. In this paper, the distribution of standard deviation was regarded as statistics fractal system, according to a large number of corrosion test data. The fractal dimensions were calculated and equal to 1.343 and 1.486 for the parallel test data and the regional corrosion test data, respectively. New CoV was proposed,through the fractal correction to describe the fluctuation of the corrosion rates. In addition, the fractal dimension tended to be stable when the parallel samples over 6 pieces. The modified CoV was independent of corrosion levels and was the best index of the random fluctuation of corrosion rate.