汽包概率疲劳损伤服从三参数威布尔分布的参数确定新方法

A NEW METHOD TO DETERMINE THE PARAMETERS BY WHICH THE PROBABILITY FATIGUE DAMAGE OF BOILER DRUM ACCORDS WITH THE WEIBULL DISTRIBUTION

结合电站锅炉汽包运行过程中发生疲劳损伤失效问题，提出一个概率疲劳损伤服从三参数威布尔分布时的形状参数ｍ、尺度参度α和位置参数Ｎ０确定的新方法。由于用解析法计算分布参数复杂及用图解法（也称概率纸法）估计时精度较低等原因，从而使三参数威布尔分布在概率疲劳损伤分析中的应用受到一定限制。本文论述了一种利用图解法与优化法相结合的方法求解其三个分布参数，并在此基础上编制出Ｃ语言计算程序，用它对几种耐热钢疲劳试验的寿命数据进行了三参数威布尔分布拟合，结果相当好，表明提出的确定威布尔分布三参数新方法是简捷与实用的。

Abstract Regarding to fatigue damage of boiler drum,the paper proposes a new method by which shape parameter m,dimension parameter α and position parameter N o can be determined when a probability fatigue damage accords with the three parameters Weibull distribution. To calculate the distribution parameters,the analytical method is considered to be very complicated and the graphic method too rough.So.the use of three parameters Weibull distribution in analysis of probability fatigue damaging is being limited in some extent. This paper describes a way to combine the graphic method with optimization to gain the three distribution parameters. Then a program has been worked out with C language. The results of this program fit very well with the data of fatigue life test on several heat-resistant steels. It shows that this new method to determine three parameters of Weibull distribution is very simple and practical.