Change of Tightness of Lined Composite Pipe in Life Cycle

In order to study the tightness change of bimetal composite pipe in the life cycle,taking X60-825 composite pipe as an example,a 1/4 plane strain finite element model of bimetal-lined composite pipe was established by using ABAQUS software.The influences of temperature and pressure on the tightness of bimetal composite pipe under manufacturing,installation,operation and out of service conditions were all discussed.The study results show that the model could accurately simulate the tightness change of bimetal-lined composite pipe in the life cycle.Under the design condition,the temperature in the operation stage has limited influence on the tightness of the composite pipe and the composite pipe will not delaminate.In the operation stage,the tightness of bimetal-lined composite pipe increases with the increase of operation pressure.Therefore,properly increasing the operating pressure within the elastic-plastic limit of bimetal-lined composite pipe is helpful to improve the tightness of the composite pipe.The results provide some reference for the research and application of bimetal composite pipe.