摘要
基于应变的失效评定图程序(Strain Based Failure Assessment Diagram,SBFAD)可以提高大范围屈服条件下的管道及环焊接头的断裂评估准确性。本文构建了含缺陷的X80管道环焊接头数值分析模型,详细阐释了SBFAD方法及其评估曲线的影响因素,明确了不同等级评估曲线的应用场景,并基于X80管道环焊接头的实测力学性能定量评估了含缺陷的X80管道环焊接头临界应变承载能力。研究结果表明:(1) Budden提出的SBFAD方法按照评估曲线的不同,可分为Option 1、Option 2和Option 3,其修订后的Option 1M和Option 2M曲线的非保守性大幅降低。BS 7910提供的Option 2要比基于Budden修订的Option 2M曲线的评估结果更为激进。(2)基于SBFAD方法中的Option 2曲线评估较大尺寸的缺陷可能会呈现非保守的结果。材料的应变硬化指数(n)值对Option 2曲线几乎没有影响,而随着n值的减小,Option 3曲线会缓慢上移,随着n值的增大,SBFAD曲线的截止线值呈明显递减趋势。(3)现有的Option 2曲线无法体现强度匹配系数的影响。随着焊缝强度匹配系数的增加,Option 3曲线逐渐上移,上移幅度则与缺陷尺寸相关,Option 2曲线在评估等匹配焊接缺陷时具备较高精度,在评估强度高匹配的焊接缺陷时,其结果可能过于保守,而在评估强度低匹配的焊接缺陷时,其结果可能是非保守的。(4)基于X80管道环焊接头的实测力学性能对其临界应变承载能力进行评估(缺陷尺寸和断裂韧性固定),Budden提出的Option 1M的评估结果最为保守,基于BS 7910-2019的Option 2评估结果最为激进。结论认为,基于SBFAD方法评估的保守性与其评估曲线、评估参数的选择密切相关,应针对评估需求选择合适的评估参数及合理的评估曲线以避免出现非保守的评估结果,研究结果为X80管道环焊接头的工程失效评估提供了理论与技术支撑。
The Strain Based Failure Assessment Diagram(SBFAD) procedure can improve the accuracy of fracture assessment of line pipes and defective girth welded joints in a large range of yield condition. In order to sufficiently reveal SBFAD method and the factors influencing its assessment curves, this paper constructs a numerical analysis model of defective girth welded joint in X80 line pipes. Then SBFAD method and the factors influencing the assessment curves are illustrated, and the application scenarios of different levels of assessment curves are clarified. Finally, the critical strain bearing capacity of defective girth welded joint in X80 line pipes is quantitatively assessed based on the measured mechanical properties. And the following research results are obtained. First, based on different assessment curves, the SBFAD method proposed by Budden can be classified into Option 1, Option 2 and Option 3, and the non-conservativeness of the modified curves Option 1M and Option 2M are reduced greatly. The assessment result of Option 2 provided by BS 7910 is more aggressive than that of Option 2M modified based on Budden. Second, the Option 2 curve based on SBFAD method may present non-conservative results when it is used to assess larger sized defects. The value of the strain-hardening index(n) of material has little influence on the Option 2 curve, while the Option 3 curve shifts slowly upward as the value of n decreases. With the increase of n, the cutoff value of the SBFAD curve shows a significant decreasing trend. Third, the existing Option 2 curve cannot represent the impact of the strength matching factor. As the strength matching factor of weld increases, the Option 3 curve gradually shifts upward,and the magnitude of the upward shift is related to defect size. The Option 2 curve has a higher accuracy in assessing equal-matched weld defects, and the assessment results may be too conservative in assessing high-strength matched weld defects and non-conservative in assessing low-strength matched weld defects. Fou
作者
王旭
帅健
张圣柱
王如君
多英全
WANG Xu;SHUAI Jian;ZHANG Shengzhu;WANG Rujun;DUO Yingquan(College of Safety and Ocean Engineering,China University of Petroleum-Beijing,Beijing 102249,China;China Academy of Safety Science and Technology,Beijing 100012,China)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2023年第2期121-130,共10页
Natural Gas Industry
基金
国家自然科学基金面上项目“基于应变的管道环焊缝断裂评估方法研究”(编号:51874324)
国家重点研发计划项目“油气管道及储运设施完整性评价技术研究”(编号:2016YFC0802105)。
关键词
有限元分析
拉伸试验
基于应变
失效评定图
天然气管道
环焊接头
断裂评定
应变承载能力
Finite element analysis
Tensile testing
Strain based
Failure assessment diagram
Natural gas line pipes
Girth welded joint
Fracture assessment
Strain bearing capacity
