压裂泵头体内腔相贯线裂尖塑性区计算与分析  

Calculation and analysis on crack tip plastic zone at intersecting line of the fracturing pump head

作　　者：周思柱[1] 魏超 华剑[1] 张思[1] ZHOU Sizhu;WEI Chao;HUA Jian;ZHANG Si(Institute for Strength and Vibration of Mechanical Structures,Yangtze University,Jingzhou,Hubei 434023,China)

机构地区：[1]长江大学机械结构强度与振动研究所,湖北荆州434023

出　　处：《中国科技论文》2018年第16期1926-1930,共5页China Sciencepaper

基　　金：国家自然科学基金资助项目(51674040);国家科技重大专项(2016ZX05038-001-LH002);湖北省自然科学基金计划资助项目(2016CFC740)

摘　　要：针对压裂泵泵头体主要失效形式,建立了含裂纹缺陷压裂泵泵头体有限元模型,分析了不同初始裂纹及工作压力情况下裂纹前缘塑性区长度,依据最大张开位移(maximum crack opening displacement,MCOD)拟合了裂纹前缘θ=0°及θ=90°处裂尖塑性区长度多项式。结果表明:内腔相贯线处裂纹前缘3°≤θ≤87°处裂尖应力状态接近平面应变状态,裂尖塑性区长度与初始裂纹及工作压力呈正相关,应用Irwin公式计算的塑性区长度能较好地吻合有限元结果;裂纹前缘θ=0°及θ=90°处于平面应变与平面应力的过渡状态,拟合的塑性区多项式与MCOD及初始裂纹有关,为研究裂尖塑性区对泵头体裂纹扩展的影响提供了一种方法。According to the main failure mode of fracturing pump head, the finite element model of pump head with crack defect was built. The plastic zone length of crack front was analyzed under different initial crack and working pressure, and the formulae for calculating the plastic zone length of the crack front at θ =0°and θ =90°were fitted according to the maximum crack opening displacement（MCOD）. The results show that the stress state of crack front at 3°≤ θ ≤87° is close to plane strain state, and the crack tip plastic zone size is positively correlated with the crack length and the working pressure. The plastic zone size under plane strain calculated by the Irwin formula can be in good agreement with the finite element results. The stress state of crack front at θ =0°and θ =90°is between plane stress state and plane strain state. The fitted formulae of the plastic lergth are influenced by the MCOD and initial crack, which provides a method for studying the plastic zone effects on the crack growth of pump head.

关 键 词：泵头体 内腔相贯线 裂纹前缘 塑性区长度 最大张开位移 

分 类 号：TE925[石油与天然气工程—石油机械设备]