Local Design of Anchoring for Thermoplastic Composite Pipes Using Adhesive Interfaces

Thermoplastic Composite Pipes (TCPs) offer greater durability compared to metallic materials, especially in deepwater and alkaline environments such as oil and gas well casings and completions, where corrosion resistance is essential and failure mechanisms at the termination remain complex. Fixation systems may fail due to slippage or rupture of the anchoring composite, worsened by geometric constraints imposed by the internal diameter of the casing. This study evaluates the mechanical performance of different end fitting geometries, materials, loading conditions, and temperatures using finite element analysis (FEA), employing three-dimensional continuum shell elements with cyclic symmetry to capture the actual behavior of the structural laminate. The model incorporates cohesive contact to evaluate the composite–metal interface, while laminate failure was investigated based on the Hashin failure criterion. The results showed that cohesive failure limits pressure of the adhesive ranged from 63 MPa to 73 MPa to 23ºC, and 46 MPa to 65 MPa to 100ºC condition, while TCP failure reached up to 122 MPa with PEEK/FC material and the EF2 geometry providing the best structural performance. The adhesive layer demonstrated robustness, with cohesive failure occurring only after the primary failure of the TCP. Under axial loading, adhesive resistance reached up to 2583 kN before debonding initiation, confirming its capacity to withstand the full test pressure and even surpass the burst limit of the anchoring system.