| The security of the heat pipe is more and more important, when the heat pipe is usedmore and more widely. In this thesis, through theoretical calculation and finite elementsimulation method, the temperature field, stress field and crack of Hulan River of heatingpipes were analyzed, and the support piers of the pipeline were simulated. With the result, theimpact of the thermal stress on heat pipes were analyzed comprehensively and thoroughly.First, it is to establish the temperature field of the pipe cross-sectional view by theoreticalcalculation and finite element simulation, and to calculate the pipeline Triplex thermal stressusing the create pipe temperature field, respectively. Ignore the mid-pipe and outer pipe in thesimplified calculation, through comparing the three-pipe heat stress and the axial force.Second, using the finite element software simulate the long straight pipe and "Z"-typepipe on the bridge end. By calculating the stress contours under temperature and internalpressure, obtain the pipeline axial force and pipe stress areas such as the minimum and themaximum. Then, analyse the weakest area where the stress was greatest in detail, to ensurethat the operation of the pipeline safety.Third, under the pier external force, establish the finite element model to simulate,which the long straight pipe is the prestressed pipe or not. From the relatively larger and thesmaller area of the pier stress determined, can we get the smaller equivalent stress of the pierwhen the long straight pipe is in the prestressed case, and make feasible suggestions for thelaying of the pipeline and the design of the pier.Finally, suppose that there is a run-through crack appearing in the weakest area of the"Z"-type pipe. Simulate the pipe crack by finite element software, and get the crack stressfield around and the J-integral of the crack tip, to make reasonable solution for the pipelinecrack maintenance.This thesis, starting in various areas, studies the effects of thermal stress, provides atheoretical basis for the optimization of the pipeline structure, processing and other aspects ofthe pipeline cracks, and has great economic value on improving pipeline safety, reliability. |
