【作者】 徐尊平；

【导师】 雷斌隆；

【作者基本信息】 西南交通大学 ， 材料加工工程， 2006， 硕士

【摘要】 压力钢管是水电工程中输水建筑物的重要组成部分,它承受着较大的内水压力以及自身的重量和水重。由于卷制或服役期间水和泥沙的冲刷原因,常在压力钢管壁表面产生大量凹坑缺陷。在水电站运行过程中压力钢管受力复杂,工况严峻,在凹坑缺陷处将产生很高的局部应力,可能在凹坑缺陷处产生裂纹并引发开裂,严重地影响压力钢管的承载能力并危及水电站的安全因此,对含凹坑缺陷的压力钢管进行力学分析和安全评定就显得非常必要了。 凹坑缺陷属于体缺陷,不易用常规的方法进行应力分析。本文结合上河坝水电站用压力钢管含表面凹坑缺陷的工程实例,采用大型有限元分析软件——ANSYS软件对钢管壁表面上在不同方向分布、不同间距和不同数量的条件下凹坑群缺陷进行了应力计算和分析,并讨论了凹坑缺陷在不同条件下对钢管应力分布情况的影响。 论文还采用“压力容器缺陷评定规范”——CVDA和“在用含缺陷压力容器安全评定”标准,两种评定方法对含表面凹坑群缺陷的压力钢管进行了安全评定。更多还原

【Abstract】 Penstock is the important constitute of the building of water-transportation of power plant, It take on biggish inner hydraulic pressure and its own weight and watery weight. Due to manufacture or scour of loam sand when it is used, It is often appear many pit-defects on the penstock’s surface. When the penstock is working, it have complica(?)d stress and create much high topical stress, it is easy create crack near the pits, this affect seriously the penstock’s ability of loading. So, it is very necessary to analyze the stress and assess the safety of the penstock with surface pit defects.The pit defects belong to valume defect, so, it is not easy to analyze the stress with general methades. This paper adopt the engineering example of penstock with pit defects used in Shangheba power plant and use finite element analysis software to calculate and analyze the stresses of the pits under different orient distribution, different distance and quantity. At last,it is discussed how the pits affect the distribution of stress of the penstock.The safety of the penstock with surface pit-defects are assessed based on criterion for pressure vessels defects assessment and safety assessment for in-service pressure vessels containing defects.更多还原