开口模型下内腐蚀缺陷管柱剩余抗内压强度

目前较少按开口模型研究缺陷管柱剩余抗内压强度,各因素对抗压强度的影响程度缺乏定量分析,较少考虑缺陷宽度、管柱径厚比等因素对强度的影响.根据非线性有限元方法,结合正交试验设计,按开口模型分析了内压载荷下缺陷管柱应力分布情况,研究了内腐蚀缺陷长度、宽度、深度、管柱外径、径厚比等参数对管柱剩余抗内压强度的影响规律.结果 表明:开口模型下含缺陷管柱抗内压强度低于端部约束模型与闭口模型.缺陷管柱无因次抗内压强度随缺陷深度增加呈线性关系降低,随缺陷长度的增加呈指数关系逐渐降低,抗内压强度随缺陷宽度增加先增大后降低;轴向沟槽形缺陷显著降低管柱的抗内压强度.缺陷深度与长度对无因次抗内压强度影响较大;管柱径厚与缺陷对无因次强度影响较小.以有限元计算结果为依据,建立了抗内压强度多因素预测模型,可为工程上含缺陷管柱抗内压强度评价提供参考.

Residual Internal Pressure Strength Analysis of Internal Corrosion Defect Pipe String under Opening Model

At present, there are few studies on residual internal compressive strength of defective pipe string based on open-ended model. Quantitative analysis of the influence of various factors on compressive strength is lacking, and the influence of defect width and diameter-thickness ratio of pipe string on strength is seldom considered. Based on the non-linear finite element method and orthogonal experimental design, the stress distribution of the defective pipe string under internal pressure is analyzed according to the open model. The influence of the length, width, depth of the internal corrosion defect, the outer diameter of the pipe string and the ratio of diameter to thickness on the residual internal pressure strength of the pipe string is studied. The results show that the internal compressive strength of the pipe string with defects under the open model is lower than that under the end restraint model and the closed model. The dimensionless internal compressive strength decreases linearly with the increase of defect depth, and decreases exponentially with the increase of defect length. The internal compressive strength increases first and then decreases with the increase of defect width. The axial groove defect significantly reduces the internal compressive strength of the pipe string. Defect depth and length have great influence on dimensionless internal compressive strength, while diameter thickness and defect have little influence on dimensionless strength. Based on the results of finite element analysis, a multi-factor prediction model of internal compressive strength is established, which can provide reference for the evaluation of internal compressive strength of defective pipe string in engineering.