含局部减薄高温管道的极限载荷研究

发布时间：2019-04-17 12:31

【摘要】：本文主要是在前人的对含局部减薄常温管道极限载荷研究的基础上,针对高温下长时服役管道的极限载荷进行研究,同时考虑由于腐蚀原因产生的局部减薄。本文首先利用Ramberg-Osgood弹塑性本构方程,结合损伤力学理论,推导了含有初始蠕变损伤的弹塑性本构。对10CrMo910材料进行了蠕变实验,通过不同的实验时间以得到不同蠕变损伤的材料,然后再对这些材料进行高温短时拉伸,得到不同损伤对应的应力应变曲线。将试验得到的应力应变曲线和含损伤的弹塑性本构关系描述的应力应变曲线进行对比,表明两者之间有一定的吻合度。其次,在高温下服役的管道会逐渐产生损伤。在最大主应力控制的情况下,损伤从内壁到外壁是渐增的；在当量应力的控制下,损伤是从内壁到外壁则渐减。用得到的含初始蠕变损伤的弹塑性本构方程,对损伤沿壁厚均匀分布的管道进行极限载荷的分析,得到损伤对极限载荷影响的一般规律；在损伤沿壁厚变化的情况下,经对管道进行极限载荷分析,得到管道的极限载荷与最大损伤呈线性关系。最后,同样用含初始蠕变损伤的弹塑性本构方程对含局部减薄的管道,同时蠕变损伤沿着管道壁厚是从内而外变化的情况进行了有限元极限载荷分析,得到了蠕变损伤、缺陷尺寸和管道极限载荷三者之间的关系。
[Abstract]:Based on the previous research on the limit load of pipeline with local thinning and room temperature, the ultimate load of long service pipeline at high temperature is studied in this paper, and the local thinning caused by corrosion is considered at the same time. In this paper, based on the Ramberg-Osgood elastoplastic constitutive equation and the damage mechanics theory, the elastoplastic constitutive model with initial creep damage is derived. The creep tests of 10CrMo910 materials were carried out. Different creep damage materials were obtained by different experimental time, and then the stress-strain curves of different damage were obtained by short-time tensile test at high temperature. The comparison between the stress-strain curve obtained by the experiment and the stress-strain curve described by the elasto-plastic constitutive relation with damage shows that there is a certain degree of agreement between the two curves. Secondly, the pipeline in service at high temperatures will gradually cause damage. Under the control of the maximum principal stress, the damage increases gradually from the inner wall to the outer wall, while under the control of the equivalent stress, the damage decreases gradually from the inner wall to the outer wall. Based on the elasto-plastic constitutive equation with initial creep damage, the limit load of pipes with uniform distribution of damage along the wall thickness is analyzed, and the general rule of the effect of damage on the ultimate load is obtained. Under the condition that the damage changes along the wall thickness, the ultimate load of the pipeline is analyzed and the linear relationship between the ultimate load and the maximum damage is obtained. Finally, the elastic-plastic constitutive equation with initial creep damage is also used to analyze the creep damage of the pipeline with local thinning, and the creep damage along the wall thickness of the pipeline is changed from inside to outside by finite element limit load analysis, and the creep damage is obtained. The relationship between the size of the defect and the ultimate load of the pipe.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH49

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