| Pipeline is the main way to convey natural gas.As the natural gas is flammable and combustible,catastrophic accidents happen after gas leakage.Defects of pipe such as Corrosion and deformation of the pipe reduce the pipe’s loading capacity and then cause potential hazardous event.In order to prevent the pipe failure,the maintenance measure is often used in the practice such as regulating pressure,repairing and replacing pipe.So fitness-for-service is propounded to know the safety,the reliability,the residual strength and the safety service life of the structure based on defect detection.The result provide scientific reference basis for pipeline maintenance measures.In this paper,the data of the pipeline are analyzed,the pipeline corrosion defects and pipes’ deformation caused by bad geological condition are discussed emphatically.At first,this paper introduces the current method of pipeline defect evaluation.Based on these methods,the finite element model of the defect pipeline was established,and the stress strain of the pipeline is gotten.The mathematical model for calculating reliability of defects pipeline is established with the safety evaluation curves of double judging criterion.The failure probability of the defect pipe is gotten.With the date from measurement,The life of corrosion pipe under the conditions of risk level is acquired based on probability theory.This paper provides scientific decision for the detection,repair and replacement of gas pipelines. |
