内压作用下异径管的应力分析及验证

利用有限元方法分析了内压作用下异径管的应力分布，结果表明：同心异径管大端向外的弯曲应力与薄膜应力叠加后使外壁组合应力下降、内壁组合应力上升，小端连接处直管内外壁均为轴向压应力；内压在非轴对称结构的偏心异径管的偏心侧大端和中部引起的环向应力最大，且偏心侧外壁的环向应力较内壁的环向应力大。实验结果与有限元分析结果一致，但存在一定误差，主要是与工程管件不均匀的力学性能及壁厚有关，因此，将直管的应力理论直接套用到异径管是不恰当的。

Stress Analysis and Experimental Proof of Reducer under Internal Pressure

The stress distribution both of concentric reducer and eccentric reducer under internal pressure was analyzed by finite element method. The results show that the combination stress on outside wall at large end should decline and the combination stress on inside wall at large end should raise after adding the bend stress to the membrane stress. The stresses of both of the outside surface and inside surface of tube,and are jointed to the small end belong to axial contract stress. As its un-axial -symmetric structure of eccentric reducer,maximum circle stress is showed at the large end and middle of eccentric side, and the circle stress on outside surface is larger than that on inside surface at the eccentric side middle of eccentric reducer. The stress distribution that surveyed by experiments is consistent with that by finite element method. But there is some errors because of the uneven mechanical property of reducer and the uneven wall thickness. The membrane shell theory of pipe under internal pressure is not well situated for the eccentric reducer.