基于信息熵的薄壁内压容器安全系数

Reliability Safety Factor of Steel Thin-wall Internal Pressure Vessels based on Information Entropy Theory

基于钢制薄壁内压容器模糊静强度的信息熵分析,从控制其模糊静强度在正常操作与压力试验时可靠度的角度,探索安全系数、试验压力系数与超压限制系数的定量关系。研究表明:(1)从等可靠度的观点,可要求薄壁内压容器屈服强度的模糊可靠度在正常操作时不低于0.992656,在气压与液压试验时分别不低于0.96926与0.7881;爆破强度的模糊可靠度在正常操作时不低于0.9999999753,在气压与液压试验时分别不低于0.999998931与0.999990226。(2)薄壁内压圆筒屈服与抗拉安全系数应分别不小于1.45与1.80;薄壁内压球形容器屈服与抗拉安全系数应分别不小于1.40与1.90;扁平绕带式容器屈服与抗拉安全系数应分别不小于1.35与2.00。(3)薄壁内压容器试验压力系数应不小于1.00。在气压与液压试验时,薄壁内压圆筒试验压力系数应分别不大于1.16与1.28,薄壁内压球壳试验压力系数应分别不大于1.19与1.32,扁平绕带式容器试验压力系数应分别不大于1.16与1.30。(4)在气压与液压试验时,薄壁内压圆筒的超压限制系数在屈服失效准则下应分别不大于0.800与0.900,在爆破失效准则下应分别不大于0.683与0.712;薄壁内压球壳的超压限制系数在屈服失效准则下应分别不大于0.929与0.943,在爆破失效准则下应分别不大于0.640与0.675;扁平绕带式容器的超压限制系数在屈服失效准则下应分别不大于0.858与0.971,在爆破失效准则下应分别不大于0.612与0.654。

The fuzzy static strength reliability, safety factor, testing pressure coefficient and o- verpressure confining coefficient of steel thin-wall internal pressure vessels during normal operation and pressure tests were quantitatively analyzed based on the information entropy theory. The researching results showed that： （1） From equal-reliability point of view, for steel thin-wall inter- nal pressure vessels, the desirable value of fuzzy yield strength reliability should be not less than 0. 992 656 during normal operation,and it should be not less than 0. 969 26 or 0. 788 1 under baro- metrical or hydraulic pressure tests. For fuzzy burst strength reliability of steel thin-wall internal pressure vessels,the desirable value should be not less than 0. 999 999 975 3 during normal operation and not less than 0. 999 998 931 or 0. 999 990 226 under barometrical or hydraulic pressure tests,respectively. （2） For cylinder vessels, the yield safety factor is equal to 1.45 and the burst safety factor is not less than 1.85;for spherical vessel or spherical heads, the factor is equal to 1.40 and the burst safe factor is not less than 1. 90;for flat ribbon-wound pressure vessels, the yield safety factor is equal to 1.35 and the burst safety factor is not less than 2.00. （3） The testing pressure coefficient of steel thin-wall internal pressure vessels is equal to or not less than 1. 00;when barometrical or hydraulic pressure test, for steel thin-wall internal cylinders, the testing pressure coefficient should not be grater than 1.16 or 1.28,for sphere-cal vessel,it should not be grater than 1.16 or 1.32,for flat ribbon-wound pressure vessels,it should not be grater than 1.16 or 1.30. （4） Under barometrical or hydraulic pressure tests; for cylinder vessels, if using yield failure criteria, the overpressure confining coefficient should not be greater than 0. 800 or 0. 900,if using burst failure criteria,it should not be greater than 0. 640 or 0, 719;for spherical vessels,if using yield failure criteria, the overpressure confining coefficient should not be greater than 0. 848 or 0. 943,if using burst failure criteria,it should not be greater than 0. 581 or 0. 680;for flat rib- bon-wound pressure vessels, if using yield failure criteria, the overpressure confining coefficient should not be greater than 0. 858 or 0. 971,if using burst failure criteria,it should not be greater than 0. 538 or 0. 658.