Mechanical Analysis Of The Manufacturing Process Of Bimetal Lined Pipe

Bimetal lined pipes are widely used in oil and gas pipeline industry.The advantages of this type of pipelines are prominent,such as cost saving,high performance in corrosion resistance and easy manufacturing.The bonding force or residual contact pressure between the surfaces of the backing steel and the CRA liner is quite important in terms of understanding the mechanical behavior o f the bimetal lined pipes.It is known that establishing higher bonding force could contribute to eliminate the liner buckling problem and enhance reliability of the lined pipe.In this thesis,the hydraulic expansion and the thermo-hydraulic expansion manufacturing processes of the mechanically lined pipes are simulated by the finite element software ABAQUS,in order to analyze their mechanical behaviors,especially the bonding force between the carbon steel outer pipe and the CRA liner pipe.Sensitivity analysis of the bonding force to different process parameters are performed by adopting the proposed finite element models.Results show that,the wall thickness of the liner pipe is the most effective parameter for hydraulic expansion process,and the thermal expansion coefficients of the liner and the outer pipes and the heating temperature have the largest influence on the residual contact pressure of the lined pipe in thermo-hydraulic expansion process.Moreover,for the hydraulic expansion manufacturing process,equations for calculating the residual contact pressure,as well as the effective hydraulic forming pressure range are derived based on the plastic hardening stress of the liner pipe.The results are consistent with the simulation results.The research results can be used as a guideline for design of the manufacturing process of bimetal lined pipes.