基于分段函数的结构动应力谱分布估计方法  

Estimation Method for Dynamic Stress Spectrum Distribution of Structure Based on Piecewise Function

作　　者：陈道云[1] 孙守光[1] 李强[1] 张亚禹 王金莎 张学苹 

机构地区：[1]北京交通大学机械与电子控制工程学院,北京100044 [2]齐齐哈尔轨道交通装备有限责任公司货车分厂,黑龙江齐齐哈尔161002

出　　处：《中国铁道科学》2016年第4期89-94,共6页China Railway Science

基　　金：国家自然科学基金资助项目(U1134201);国家"八六三"计划项目(2012AA112001);北京交通大学基本科研基金资助项目(2016YJS130)

摘　　要：以某型动车组制动吊座的疲劳关键点为例,采集并处理其动应力数据,得到其实测动应力谱;针对等组距直方图不能满足动应力谱分布估计的问题,提出非等距分组的方法。分别使用工程领域常用的截尾正态分布函数、对数正态分布函数和威布尔分布函数以及色谱领域常用的Giddings分布函数进行实测动应力谱的分布拟合,结果表明：单一使用某一分布函数得到的分布拟合结果不能通过卡方检验,且截尾正态分布函数的拟合精度最低;Giddings分布函数对前6组数据拟合得较好,威布尔分布函数对中间组（7～12组）数据拟合得较好,对数正态分布函数对尾部（13～17组）数据拟合得较好。因此根据不同分布函数在不同谱级段体现出的拟合优势,构建分段函数分布模型,并顺利通过了卡方检验。基于分段函数分布模型得到的结构动应力谱的Miner线性累积损伤与实测谱损伤的总体走势一致,且其每级损伤均大于实测谱损伤,从而得到对结构疲劳寿命做出偏安全的预估。Taking the fatigue key point of the braking hanging bracket of certain EMU for example,the dynamic stress data were collected and processed and the measured dynamic stress spectrum was obtained.In view of the fact that the histogram of equal group interval could not estimate the dynamic stress spectrum distribution,a method of unequal group interval was proposed.The truncated normal distribution function,logarithmic normal distribution function and Weibull distribution function commonly used in engineering field as well as Giddings distribution function commonly used in chromatography field were adopted respectively to carry out the distribution fitting of measured dynamic stress spectrum.The results showed that the distribution fitting result that came from a certain single distribution function could not pass chi-square test.The fitting accuracy of truncated normal distribution function was the lowest.The fitting accuracy of Giddings distribution function was better for the first 6groups of data.The fitting accuracy of Weibull distribution function was better for the central groups（group 7to group 12）of data.The fitting accuracy of logarithmic normal distribution function was better for the last 5groups（group 13 to group 17）of data.The piecewise function distribution model was then established according to the fitting advantages of different distribution functions at different spectral levels and passed chi-square test smoothly.The Miner linear cumulative damage trend of structure dynamic stress spectrum obtained from piecewise function distribution model was consistent with the measured one,and its damage of each level was greater than the measured one,thus the fatigue life of structure could be predicted on the safe side.

关 键 词：结构动应力谱 分布估计 截尾正态分布 对数正态分布 威布尔分布 Giddings分布 分段函数分布模型 Miner线性累积损伤 结构疲劳寿命 

分 类 号：U266[机械工程—车辆工程]