整圈未焊透三通塑性极限内压的影响因素解析

三通是压力管道系统中不可缺少的管道元件，但国内对存在未焊透缺陷的三通研究很少。基于有限元方法分别计算了插入焊和跨接焊两种整圈未焊透三通，插入焊三通有限元模型所得的无量纲化塑性极限内压值要大于跨接焊三通有限元模型所得值，在后续工作中可用后者模型替代前者，既能保证安全又大大减少工作量。选取了7个参量，分别计算分析了每个参量对整圈未焊透三通无量纲塑性极限内压的影响程度。确定了三通强度因子、主管管径比和未焊透深度为整圈未焊透深度敏感三通无量纲塑性极限内压的主要影响因素；其中前两者为整圈未焊透深度非敏感三通无量纲塑性极限内压的主要影响因素。

INFLUENTIAL FACTORS OF PLASTIC LIMITING INTERNAL PRESSURE FOR WELDED PIPE TEE WITH INCOMPLETE PENETRATION ALONG INTERSECTING LINE

Pipe tee is a kind of indispensable pipe fitting for the pressure pipeline system. However, the researches into the pipe tees with incomplete penetration defects are inadequate. Based on the finite element method, pipe tee with inserted welding and pipe tee with bridged welding are computed separately, and the result indicates that plastic limiting internal pressure of the former is slightly larger than the latter. Therefore, the latter model can take the place of the former, so that the security can be ensured and the workload can be greatly reduced. In this paper, seven parameters, including Do2/D01, T2/T1, K1, c, Do1, L and σs, are selected to calculate and analyze the influential degree of each parameter on the plastic limiting internal pressure for welded piping tee with incomplete penetration along intersecting line separately. Ptd, K1 and c are recognized as major effect factors of plastic limiting internal pressure of pipe tee which is sensitive to the incomplete penetration depth; while Ptd and K1 are major effect factors of pipe tee which is non sensitive to the incomplete penetration depth.