Finite Element Simulation Analysis on Bulging Defect in Repair Process of Composite Plate Pressure Vessels

The repair process of pressure vessel composite plate involves the use of corrosion-resistant alloy pipe lining to effectively solve the corrosion issues in highly corrosive gas field pipelines. However, the welding failure and bulging of the lining plate after the repair process affect its application in the oil and gas transportation industry. For the bulging issues in the repair process of composite plate pressure vessels, an equivalent analysis model of solder joints under different initial bulging heights and solder joint diameters was established using ANSYS finite element simulation. The influence of different bulging heights and solder joint diameters on the stress of solder joints during the compression process of the lining plate was systematically analyzed. The results show that when the lining plate is subjected to a pressure of 11.5 MPa, with the increase of bulging height from 1 mm to 5 mm, the average tensile stress of the center weld point and the shear stress of the solder joint nearest to the center solder joint gradually increase. The failure mode of the center weld point is pull-off, while the failure mode of the solder joints closest to the center solder joint is shear failure, and the failure risk is higher for the solder joints closest to the center solder joint. With the increase of solder joint diameter from 8 mm to 12 mm, the shear stress of the solder joints closest to the center solder joint also decreases, indicating that increasing the solder joint diameter can reduce the failure risk of solder joint.