Numerical Analysis For Plastic Limit Load Of Piping Branch Junction And Strength Of Especial Piping Branch Junction

Piping branch junction, as one of the important components in pressure piping system, is widely used in petrochemical engineering, power plant, oil and gas transportation etc. Because of the geometric complexity of the tee and the difficulty of mathematic analysis, there has not been yet a mature and simple plastic limit load computing method. Considering the general failure mode of the piping tee is plastic failure and the plastic limit load for the piping tee is an important design parameter in engineering, the systematic analysis and the engineering calculation of the limit load for piping tees become the key point of their integrality assessment technology. By means of finite element method and theoretical analysis, the plastic limit load for piping branch junctions were studied in this paper. On basis of the analysis about the limit load solutions of piping branch junction, the influence of the geometric size of piping branch junction under internal pressure on the plastic limit load was analyzed in detail. The main contents and achievements were summarized as follows:(1) On the basis of the three-dimension finite element models of piping branch junction and the flow of numerical analysis for plastic limit established, the plastic limit pressure database about branch junctions were established and the engineering estimation equations for limit load of piping branch junction, under internal pressure, were created. The testing data of literature[1] were used to validate the correctness of the method of analyse the plastic limit load. Eventually, the strength-deformation characteristic piping branch junction under the plastic limit load were investigated in detail.(2) Taken example for the especial piping branch junction, the three-dimension finite element models of the especial piping branch junction were established. The influence of thwartwise tendon of the especial piping branch junction under internal pressure on the plastic limit load and the strength-deformation characteristic of piping branch junction were investigated in detail. The strength of the especial piping branch junction was investigated, which is helpful to finalize of the design.