PE80聚乙烯管道焊接接头的应力松弛模型验证及安全评价

Stress Relaxation Model and Safety Assessment of Polyethylene Pipe Welded Joints

采用实验方法研究聚乙烯(PE)管道焊接接头在机械载荷条件下的应力松弛行为,通过松弛试验得出用Prony级数表示的PE管道焊接接头的本构模型。结果表明,PE管道焊接接头的松弛曲线与PE管道木材的松弛曲线相似;结合有限元分析软件Abaqus,建立PE80焊接接头的裂纹缺陷模型,导入PE管道焊接接头与PE管道母材的Prony级数,对含裂纹缺陷PE管道的应力强度因子进行计算;借鉴GB/T 19624—2004金属管道的评定标准,给出适合PE材料的断裂判据,比较PE材料的临界应力强度因子(KIC)及计算得出的应力强度因子(KI)的大小,进而通过断裂判据对含缺陷PE管道进行安全评价。

This paper reported a study on the stress relaxation behavior of polyethylene（PE）pipewelded joint under the mechanical load condition by an experimental method.A crack defect model was established for PE pipe-welded joint by a combination of the finite element analysis software Abaqus,and the stress intensity factor for the PE pipe with crack defects was calculated by importing the Prony series of PE pipe-welded joint and pipe-grade PE resin.This article provides a proper fracture criterion for PE materials to determine their critical stress intensity factor and stress intensity factor so that a safety assessment could be well conducted for defective PE pipes.