Finite Element Simulation And Structural Buckling Of The Six - Stage Branch Well Bifurcation Device

This thesis, according to the theory of structure instability, aims at the difficulties appearing in the process of designing and preparing level6multilateral branching device. It uses the analogue simulation of the computer finite element simulation to study the design and preparation of branching device. The research content mainly includes:the structure of branching device, the design of size, material selection, structure instability and ultimate load, etc.According to the simulation results of finite element simulation and the bulge deformation appearing in the process of preparation, this thesis adopts the modern analysis methods, such as OM、SEM、EDS and the mechanics performance test to study the structure of the organization of10CrMnMoSi and the mechanics performance.(1) According to relevant data provided by a oilfield, in view of the branching device of the problems in the design process, and the pressure sealing ability, refer to a mature inclined tee structure design, set up a branching device based on the theory of the structural buckling design system, include suppression structure, material, wall thickness and pipe diameter.(2) The finite element analysis software and unit types are selected, the finite element analysis model of level6multilateral branching device is established. The internal pressure load type and constraint way of branching device are determined.Through a large number of finite element trial and data analysis to identify buckling mode and state of stress-strain of branching device under internal pressure loading, and found the factors of level6multilateral branching device buckling deformation,including wall thickness, material and structure.(3) The competent limit internal pressure as bifurcation device internal pressure load, the stress-strain of branching device is analyzed.According to ASME boiler pressure vessel code1/2times elastic slope criterion to determine the limit load level6multilateral branching device, and based on the tee nozzle-vessel junction area shape limit load approximate solution for validation.(4) According to the normorous analysis to the normalizing and the Q&P process of lOCrMnMoSi steel welding joint, the steel welded line has some effects to the unstability and deformation of level6multilateral branching device. On the basis of observation to strentching, rushing and metallography experiment, the tissue hardening phase of Q&P process of lOCrMnMoSi welding joint increased; and crystalline grain refined; mechanical property improved obviously; yield strength and tensile strength also improved; solidity, extensibility and impact ductility advanced; and the scanning to welded joint line found that those elements are well-distributed. The improvement on structure property of lOCrMnMoSi steel welded intersection line after Q&P process, has a favorable influence to against the unstability and deformation of level6multilateral branching device.(5) On the basis of the former analysis and combine with the engineering practice, after Q&P process, the function of10CrMnMoSi can satisfy the lining-up and using requirement of level6multilateral branching device; with the use of design and processing plan, and machining, lining-up to level6multilateral branching device, the testing of pressure preserving property can satisfy the requirement and expand successfully.