Theoretical and experimental study on the change of mechanical properties of pipelines before and after reel-laying

During the reeling process of the reel-lay method, the pipeline undergoes multiple bending deformations, resulting in multiple plastic deformations, which affects the mechanical properties of pipeline materials. This paper innovatively describes the calculation method of the overall stress of the pipe after reel-laying based on elastoplastic self-reinforcing theory and bilinear strengthened constitutive model, and clarifies the influence of plastic deformation of reel-laying on the performance strengthening of pipe. Through the comparative test of the mechanical properties of the pipe before and after reel-laying, the accuracy of the theoretical results is verified. The results show that there will be residual strain in the pipe after reel-laying. Plastic deformation will improve the performance of the pipe material, the tensile, compression, bending and torsion resistance of the pipe are strengthened after reel-laying. Theoretically, the maximum potential increase is 45.16%, and experimental measurements have shown conformity to theoretical values.