An Analytical Treatment of Buckling and Instability of Tensile Armors in Flexible Pipes

The present paper addresses aspects related to local buckling and instability of tensile armors in flexible pipes. Analytical models for evaluating the tensile armor buckling capacity in both transverse (radial and lateral) directions are presented based on formulating the linearized differential equation describing transverse stability of the thin curved wire assuming no friction. Then analytical models for the ultimate capacity of the outer sheath and antibuckling tape are formulated and a combined criterion for radial instability is proposed based on considering radial buckling of the tensile armor, wire yield failure, and the ultimate capacity of the outer sheath and tape. Thereafter, a study is performed comparing the proposed models with test data and alternative models available in the literature.