内压作用下偏心异径管的应力分析

Stress Analysis of the Eccentric Reducing Pipe under the Effect of Internal Pressure

为了对异径管的设计、生产提供理论依据和计算方法,对异径管中的偏心异径管进行了分析研究,得到了其应力分布规律,确定了危险点。为了减少应力集中的影响,在异径管的大小端分别加了一段直管,在对称面上施加对称约束,在大端直管端面施加轴向和径向约束。分析结果表明,偏心侧内外壁的环向应力曲线总体趋势相似,大端的应力要比小端的应力大;在同样壁厚等级和相同的公称压力下,当异径比增大时,环向应力和相当应力的极值出现位置都有由大端朝小端移动的趋势;适当增加偏心异径管的长度能减小危险点的应力集中程度。

To provide the theoretical basis and calculating method for the design and production of reducing pipes,the eccentric reducing pipe was studied to obtain its stress distribution law and to determine the dangerous point.An attempt was made to optimize the design of the reducing pipe.To reduce the effect of stress concentration,a straight tube was added onto the large and small ends of the reducing pipe,the symmetric constraint was imposed on the symmetric plane and the axial and radial constraints were imposed on the end face of the straight tube at the large end of the reducing pipe.The analysis shows that there is a similarity for the general trend of annular stress curves of the external and internal walls on the eccentric side and the stress of the large end is greater than that of the small end.Under the same wall thickness level and the same nominal pressure,the location of the extreme of annular stress and equivalent stress tends to move from the large end to the small end.Proper reduction of the length of eccentric reducing pipe can reduce the stress concentration of the dangerous point.