NONLINEAR BUCKLING SENSITIVITY ANALYSIS OF THIN-WALLED LINED COMPOSITE PIPE LINER

In order to study the buckling failure of lining delamination of thin-walled lined composite pipe, a numerical analysis model was established by using bilinear cohesion relationship, the buckling mode and critical load of the composite pipe obtained by linear buckling are taken as reference values, the interlayer initial defects were introduced to carry out the nonlinear buckling analysis on the composite pipe lining structure with thin wall lining. The relative displacement curve and deformation morphology of the relative displacement of the lining with the change of external pressure were obtained, and the results are consistent with the existing test results. Based on this model, the buckling sensitivity of lining pipe was analyzed. The results show that the size of interlayer initial defect is the main factor that affects the critical buckling pressure of liner, but it has little influence on the propagation pressure after buckling; However, the increase of interlayer bonding effect significantly improves the buckling resistance and propagation pressure of lining pipe; The ratio of outer tube wall diameter to thickness and liner thickness have significant effects on the critical buckling pressure of liner. The research results provide a reference for determining the interlayer bonding effect and the optimal design of the minimum thickness of the inner liner.