钢制薄壁外压容器稳定性的模糊可靠度

STABILITY FUZZY RELIABILITY OF STEEL THIN-WALL EXTERNAL PRESSURE VESSELS

应用数理统计方法,分析了钢制薄壁外压球形封头稳定性的不确定性特征。基于信息熵模糊性度量与随机性度量相等可实现模糊等效随机的原理,将钢制薄壁外压容器的模糊临界失稳强度等效为随机强度,建立模糊强度-载荷随机模型,以按我国标准设计与制造的钢制薄壁外压容器为研究对象,探索其稳定性在正常操作与压力试验时的模糊可靠度。研究表明:(1)薄壁外压球形封头临界失稳强度的实测值与理论预测值之比,是基本符合正态分布的模糊变量。(2)在保持外压差的外压试验时,薄壁外压球形封头稳定性的模糊可靠度为0.999 998 693;薄壁外压圆筒稳定性的模糊可靠度为0.999 999 999 999 996 85。(3)在正常操作时,薄壁外压球形封头稳定性的模糊可靠度为0.999 998 494;薄壁外压圆筒稳定性的模糊可靠度为0.999 999 999 999 947 4。

The non-definitive characteristic of steel thin-wall external pressure spherical heads stability was analyzed by using the method of statistics.The fuzzy critical strength in buckling was transferred into related random of steel thin-wall external pressure vessels,respectively,based on the information entropy theory that fuzzy entropy was equal to probability entropy.Fuzzy strength-random load model was build,and the stability fuzzy reliability of steel thin-wall external pressure vessels were researched when keeping external pressure quantitative difference of barometrical or hydraulic pressure tests and under normal operation.The research results show that:(1) For steel thin-wall external pressure spherical vessels or spherical heads,the rate is a fuzzy variable with normal distribution that between the testing data of critical strength in buckling and the theoretical expected.(2) When keeping external pressure quantitative tests,the stability fuzzy reliability of steel thin-wall external pressure spherical vessels or spherical heads is equal to 0.999 998 693,while that of steel thin-wall external pressure cylinders is equal to 0.999 999 999 999 996 85.(3) Under normal operation,the stability fuzzy reliability of steel thin-wall external pressure spherical vessels or spherical heads is equal to 0.999 998 494,while that of steel thin-wall external cylinders is equal to 0.999 999 999 999 947 4.