基于宽板拉伸的错边环焊缝应力集中试验与模拟

应力状态是环焊缝合于使用评价的关键因素,而错边会引起环焊缝结构的不连续性,导致焊缝所受应力状态发生变化。为了探讨含错边环焊缝在外加载荷下的力学行为以及应力分布情况,通过宽板拉伸试验对含错边的环焊缝应力集中现象进行研究,建立有限元模型对其进行验证,对比了BS 7910-2013《金属结构中缺陷验收评定方法导则》和GB/T 19624—2004《在用含缺陷压力容器安全评定》推荐方法所得的计算结果。研究表明:错边会导致明显的焊缝应力集中,BS 7910-2013计算得到的应力集中系数与宽板和有限元模拟得到的结果相比保守度较为合理。含错边管道环焊缝现场缺陷合于使用评价时,推荐采用BS 7910-2013对错边进行应力集中等效处理。

Stress concentration test and simulation of girth weld with misalignment based on wide plate tensile test

The stress state is the key factor for the fitness-for-service assessment of girth weld, and the misalignment causes the discontinuity of girth-welded structure, which changes the stress state of girth weld. In order to explore the mechanical behavior and stress distribution of girth weld with misalignment under the action of external load, the stress concentration of girth weld with misalignment was studied through wide plate tensile test, and verified by establishing a finite element model. Additionally, comparison was made with the calculated values obtained with the recommended method specified in BS 7910-2013 Guide to methods for assessing the acceptability of flaws in metallic structures and GB/T 19624-2014 Safety assessment for in-service pressure vessels containing defects. The research shows that misalignment can lead to obvious stress concentration in weld, the stress concentration coefficient calculated according to BS 7910-2013 is moderately conservative compared with the results obtained through the wide plate tensile test and finite element simulation, and for defect fitness-for-service assessment of girth weld of pipe with misalignment, equivalent stress concentration treatment of misalignment according to BS 7910-2013 is recommended.