内压作用下异径弯管的应力分析

Stress Analysis of Reducing Bends Under Internal Pressure

为了对异径管的设计、生产提供理论依据和计算方法,对内压力作用下的异径弯管进行了有限元分析研究。建立了异径弯管的力学模型,计算了异径弯管在内压力作用下的应力,讨论了异径弯管的环向、径向和轴向应力的变化特征,确定了异径弯管的危险部位及其应力变化规律;并对异径比对异径弯管危险点的应力集中的影响情况进行了研究,指出异径弯管危险点的应力随异径比的增大而增加;同时探讨了改善异径弯管应力集中的途径,指出增加异径弯管壁厚是减小应力集中的有效手段。

To provide the theoretical basis and calculating method for the design and production of reducing pipes, the reducing bends under interal pressure were studied with the finit element method. The mechanical model of a reducing bend was established, and the characteristics of the reducing bend were discussed with the circumferential, radial and axial stresses, the stress distribution and the dangerous points obtained. The stress concentration at the dangerous points is found to increase with the ratio of different diamters. The results show that increase of the reducing bend wall thickness is an effective means to mitigate the stress concentration.