Analytical and experimental postbuckling of conditioned cables

This paper studies the behaviour of a homogeneous cable in a horizontal rigid duct and<br />loaded by an axial compressive force. This behaviour is characterized by spatial buckling modes, named<br />sinusoidal and helical, due to friction and total or partial cable locking. The evaluation of critical buckling<br />loads involved by drilling technology has been studied by many authors. This work presents a new<br />formulation, taking the friction effects into account, for the transmission of the axial load during the<br />postbuckling process. New analytical expressions of pitches in both buckling cases are also given. A life-sized<br />bench is presented, which permits to study the laying of optical fiber cables by squeezing them into<br />an underground duct. Finally, analytical solutions are compared with experimental tests and finite element<br />simulations.