耐腐蚀RD理论和方法

THEORY AND METHOD OF ANTI-ERROTIC RELIABILITY DESIGN

腐蚀大多是局部腐蚀 ,其特点是某一局部腐蚀深度超过许可值即产生腐蚀失效 ,而且腐蚀深度是与时间有关的随机变量。对耐腐蚀可靠性计算来说 ,最主要的是确定腐蚀的几个基本变量正确的概率分布类型。文中分析腐蚀的特点和现有几种耐腐蚀可靠性研究理论的不足之处 ,在前人研究的基础上 ,借助数理统计理论进行计算推导 ,得出作为腐蚀的两个主要基本变量即腐蚀深度和腐蚀寿命的概率分布类型———腐蚀深度值的概率分布形式呈Ⅰ型极大值分布、腐蚀寿命值的概率分布呈Ⅰ型极小值分布的结论。据此建立耐腐蚀可靠度和耐腐蚀可靠寿命的数学模型 ,利用实验统计数据进行实例计算 ,并与正态分布耐腐蚀RD理论的计算结果进行分析对比 ,证实用正态分布耐腐蚀RD理论计算耐腐蚀的可靠性是行不通的。

Most of erosion are part erosion whose character is that the corrosion destroy would happened if the corrosion deepth exceeded the maximum value which is permited. Moreover,erosion deepth is time-oriented random value.It is most important to the computing of anti-erosion reliability that make sure the distribute set of the random value of erosion. In this article,the author analysis the character of erosion and the faults of some theory about anti-erosion reliability. Based on the reseach of pioneer and using the theory of value statics,the author compute and draw out the conclusion that the distribute sets of the two main variables of erosion——the variables of erosion deepth is Ⅰ-type maximum distributed and the variable of anti-erosion life-span is Ⅰ-type minimum distributed, establish the mathematical model of anti-erosion reliability and anti-erosion life-span reliability.In the last,the author give a example calculationed using the value which be gotten from experiment, compare the computing result with the result calculated with assumption that the set of variables is normally distributed,and prove that it is unacceptable computing the reliability with the assumption that the distribute sets of corrosion variables is normally distributed.