Analytical and experimental postbuckling of conditioned cables

This paper studies the behaviour of a homogeneous cable in a horizontal rigid duct andloaded by an axial compressive force. This behaviour is characterized by spatial buckling modes, namedsinusoidal and helical, due to friction and total or partial cable locking. The evaluation of critical bucklingloads involved by drilling technology has been studied by many authors. This work presents a newformulation, taking the friction effects into account, for the transmission of the axial load during thepostbuckling process. New analytical expressions of pitches in both buckling cases are also given. A life-sizedbench is presented, which permits to study the laying of optical fiber cables by squeezing them intoan underground duct. Finally, analytical solutions are compared with experimental tests and finite elementsimulations.