The Study On Bearing Capacity Of FRP/Steel Composite Pipeline Under Internal Pressure Analysis And Experimental Study

Nowadays,in order to meet the ever-increasing large amount of transportation,oil and gas pipelines are faced with engineering demands such as high pressure,large diameter and long-distance transportation.Higher requirements are put forward for the material and structure of pressure pipeline,including better stress,stability,durability and considering its economy.According to the characteristics of the pressure pipeline,it should not only meet certain strength,plasticity,good weldability and the ability to control crack development,but also ensure the anti-corrosion performance of the pipeline in complex environment.The advantages of fiber composites such as light weight,high strength,corrosion resistance,fatigue resistance and easy construction can make up for the deficiency of single metal pipe.In the case that a single material cannot achieve,such a purpose can often be achieved through composite materials or composite structures matched by materials.At present,there are many kinds of research and development of non-metallic pipe,but the fiber composite steel pipe formed by winding fiber composite material on the outer wall of steel pipe is an effective,convenient and economical solution.Based on the relevant theoretical knowledge and experimental research of composite materials,this paper studies the failure mode and influencing factors under the action of internal pressure of composite pipes through the internal pressure test of composite pipes,and then determines the calculation formula of the bearing capacity model of FRP/ steel composite pipes,providing certain reference for the design and calculation of FRP/ steel composite pipes.On the basis of summarizing the problems existing in oil and gas pipeline transportation at home and abroad and the related research progress of composite pipeline,this paper sorts out and theoretically analyzes the factors that have great influence on the mechanical properties of FRP/ steel composite materials.On the basis of experiments,macroscopic uniaxial tensile constitutive models of fiber volume content,steel volume content and laying Angle were established.Since the pipeline is mainly in a circumferential tensile state under the action of internal pressure,a calculation model for the bearing capacity of FRP/ steel composite pipeline under internal pressure can be established based on the constitutive model.Finally,the test results of the pipeline are compared with the theoretical results for verification.At this stage to the design of the composite pipe using the finite element calculation is one of the ways of generally taken into account by its designer,the related finite element model based on fiber reinforced composite steel pipe,consider FRP/steel composite material constitutive equation applied to the finite element calculation,save due to the fiber properties modeling cumbersome process,the test results with the results of numerical calculation,FRP/steel composite material constitutive model was verified in the numerical calculation within a certain range of accuracy.