Wrinkle behavior of adhesive lined pipe under cyclic bending

The wrinkle behavior threatens the life and structural integrity of lined pipe, which is a typical composite structure. A new lined pipe with an adhesive layer exhibits excellent resistance to wrinkling. However, the mechanism of wrinkling in adhesive lined pipe remains unclear. In this paper, the wrinkle behavior of the new adhesive lined pipe is studied numerically. Firstly, the wrinkle behavior of adhesive lined pipe structure under cyclic bending load is examined by the finite element method. Secondly, the effect of the length of defects in the adhesive layer is studied. Finally, the influence of local welding and Glue-Free-Zone (GFZ) on the structural stability of the adhesive lined pipe is verified. The results imply that defects within the adhesive layer are a significant factor in wrinkling formation, with wrinkles forming in defect areas. The larger the defect size, the more severe the wrinkle behavior becomes, leading to greater damage to the bonding layer. Results also suggest that the design of GFZ and local welding in adhesive lined pipe structures is more reasonable, as wrinkle behavior in these areas under cyclic bending loads is minimal and does not cause damage to the bonding layer.