Research On Numerical Simulation Of Cracked Pipeline And Its Secondary Development Application Based On ABAQUS

After China's entry into WTO,China's economy has developed rapidly,and oil and gas are regarded as the "blood" of economic development.In recent years,China's dependence on oil and gas has become increasingly high.Oil and natural gas are imported by sea transportation and land pipeline transportation.During the service of long-distance pipeline,many problems in pipeline operation have gradually appeared.The uneven settlement of soil around buried pipeline makes the pipeline stress concentration and pipeline crack defects have become the main causes of pipeline accidents.In order to improve the efficiency of analysis and calculation,a simulation system based on Java and ABAQUS secondary development is designed in this paper,aiming at the complicated operation of ABAQUS and the complex data extracted in the process of analysis and calculation.Learn and guide.Based on the basic theory of fracture mechanics,this paper establishes the calculation models of pipelines with cracks under different boundary conditions.The effects of internal pressure,pipe wall thickness,crack shape ratio and soil settlement on pipelines are discussed by numerical simulation.The stress intensity factor and J integral value at the crack are calculated by ABAQUS analysis and calculation method.The variation law of stress intensity factor and J integral value is analyzed.Based on this,some measures which can slow down crack propagation and lead to pipeline failure are put forward.When the boundary conditions are ideal,based on elastic fracture mechanics,the effects of different factors on the axial cracks of two-dimensional pipelines and elliptical surface cracks of three-dimensional pipelines are analyzed.The variation of stress intensity factor of two-dimensional pipe axial crack under different internal pressure,wall thickness and relative depth of crack is obtained.At the same time,the variation of stress intensity factors of three-dimensional circular/axial elliptical surface cracks under different crack shape ratio,relative crack depth and internal pressure is also obtained.Based on elastic-plastic fracture mechanics and pipe-soil non-linear contact model,the effects of different factors on pipelines with circumferential/axial surface cracks are analyzed when the boundary conditions are non-uniform settlement.The stress and strain of the pipeline as a whole and the J integral value at the crack are obtained under different factors such as the length of the settlement zone,the depth of settlement and the types of soil.The axial crack and the circumferential crack are compared simply.In order to solve the problems of repeated modeling and inconvenience in extracting result data in the study of cracked pipelines under uneven settlement,a simulation and analysis system for solving the appeal problem is designed and developed by means of the secondary development interface provided by ABAQUS software itself,the advanced programming language Java and other related components.With this system,researchers only need to input relevant calculation parameters.After submitting the calculation,the system can automatically generate the result file.At the same time,the relevant modules of the system will automatically extract the data needed in the result file and store it in the MySQL database.The structured stored data is convenient for data management and query.The query data will be displayed in the form of a broken line graph,which is convenient for researchers to analyze the law of changc.At the same time,the system also provides the export function of structured data to facilitate researchers to use the result data according to their own needs.The system simplifies the whole analysis process,avoids repetitive operation in the analysis process,and improves the efficiency of analysis.Moreover,the secondary development method proposed by the system can also provide reference for other personnel engaged in related work.