A modal finite element approach to predict the lateral buckling failure of the tensile armors in flexible pipes

摘要

This paper proposes a finite element (FE) modal approach to determine the critical loads and buckling mode shapes associated with the lateral buckling of the tensile armors in flexible pipes. This approach is based on pre-curved and twisted beam finite elements that are restrained to slide on the surface of a torus. The influence of the pipe's bending is addressed by assuming that the pre-buckling configuration of the tensile armors are geodesics or loxodromes of a torus and, moreover, friction effects are approximated using elastic springs. The proposed FE approach is employed in the classical buckling analyses of different tensile armors of several flexible pipes that have been previously studied in the public literature. The conducted analyses indicated that the buckling modes are sinusoidal and the pre-buckling configuration of the tensile armors in bent pipes affects their lateral buckling load. Moreover, friction between layers increases the lateral buckling resistance of the armor. Finally, comparisons with experimental and numerical results available in the literature indicates that the proposed approach is promising.