中文摘要：

X52管线钢广泛应用于石油天然气长输管道工程,具有良好的力学特性：强度高、塑性好。其本构关系的研究确定、矩阵表达及失效判据的建立是研究的主要内容。通过对比该材料的静力拉伸实验结果和Ramberg–Osgood本构模型,发现εεP0.2时,Ramberg–Osgood本构方程能够比较准确地反映X52管线钢的拉伸应力–应变关系,但当ε＆gt;εP0.2时,基于Ramberg–Osgood模型所得理论本构曲线与实验结果有较大的误差。基于此,对Ramberg–Osgood本构模型做出了修正,提出了X52管线钢在单向拉伸状态下的全局二段式应力应变关系式,并建立了X52管线钢本构关系的矩阵表达式。根据X52管线钢塑性极好的特点,分别研究了塑性材料基于应力的失效判据和基于应变的失效判据,给出了X52管线钢的应变控制失效准则。

英文摘要：

X52 pipeline steel is widely used in long-distance oil and gas pipeline engineering. This kind of material has its unique mechanical properties ： high strength and good plasticity. The establishment of its constitutive relation, matrix presentation and failure criterion are the main content of this study. By comparing the static tensile experimental result and the Ramberg-Osgood constitutive model, we found that when ε ≤ εP0.2, the Ramberg-Osgood constitutive equation could accurately reflect the X52 pipeline steel tensile stress-strain relationship. When ε 〉 εp0.2, however, the theoretical constitutive curve which is based on the experimental results of Ramberg-Osgood constitutive model has large error. Based on this, we have made a correction on the Osgood constitutive model and proposed X52 pipeline steel global 2-phase stress strain relation in the condition of unidirectional pull-up, and then established the matrix expression of the constitutive relation of X52 pipeline steel. According to X52 pipeline steel excellent characteristics, this paper studied the plastic material stress failure criteria and strain failure criteria, then provided the strain failure criterion of X52 pipeline steel.