Instability of a cracked cylindrical shell reinforced by an elastic liner

Elastic liners are used for in situ repair and retrofitting of pipes as a cost effective alternative to the replacement of damaged parts and sections. In this paper, we studied the role of an elastic liner on the buckling behavior of a cracked cylindrical shell using finite element method. A special meshing scheme that could mimic the stress singularity at the crack tip was employed to model the cracked shells. Linear eigenvalue analysis was carried out to study the effect of crack geometry (length and orientation) as well as the material properties and thickness of the elastic liner on the buckling load and buckling shape of the cylindrical shell. We considered a combination of axial compression and internal pressure which is a typical loading for pipelines and pressurized liquid-retaining structures. Our results show that cracked shellʹs strength and mode of buckling for different crack length and orientations can be largely influenced by thickness and relative stiffness of the liner layer. In particular we report a gradual transition from local to global instability due to these size and orientation effects. Finally, the role of internal pressure on structural stability and local buckling of cracked shells, which strongly depends on the crack orientation and liner thickness, is discussed.