Liner collapse behavior and failure evolution mechanism of adhesively bonded mechanically lined pipes under adhesive interface constraint

Deep-sea oil and gas transportation pipelines are subjected to high external pressure and complex marine environments during long-term service. Liner collapse failure is a critical issue affecting the structural integrity and service reliability of Adhesively Bonded Mechanically Lined Pipe (ABMLP), while the mechanical response and damage evolution behavior of adhesive interfaces have a significant influence on the liner collapse process. In this study, an experimental and numerical approach was adopted. The key adhesive parameters were obtained through single-lap shear tensile tests, and a finite element mechanical model of the composite pipe incorporating adhesive interfaces was established based on the Cohesive Zone Model (CZM). The fluid cavity loading method was employed to simulate the constrained deformation and collapse evolution of the liner under deep-sea conditions. The results demonstrate that the adhesive layer provides an elastic support effect through continuous interface bonding, enhances the load transfer capability between the outer pipe and liner, and changes the collapse evolution mode of the liner from localized instability to progressive coordinated deformation. Compared with Mechanically Lined Pipe (MLP), the critical collapse pressure (P c ) of ABMLP is increased by 52.73 %. Increasing the normal interface stiffness and damage displacement of the adhesive layer enhances the interface constraint capability and delays damage propagation, whereas the adhesive layer thickness has a limited influence on the liner collapse pressure. This study reveals the coupled mechanism between adhesive interface damage evolution and liner collapse failure, providing a reference method for structural design, failure prediction, and integrity assessment of deep-sea composite pipelines.