Numerical simulation of the radial compression of carcass layers of unbonded flexible pipes

The interlocked carcass layers of unbonded flexible pipes are designed to resist the radial compression failure due to installation, storage and transportation. A three dimensional finite element model is developed to simulate the radial compression behavior of the carcass under radial forces. At the same time, by simplifying the carcass into a ring, an analytic formula of the radial compression stiffness of a ring under radial force is deduced for the carcass. A testing rig is also established for the radial compression of the carcass. Through the radial compression test of carcass specimens, the correctness of the finite element model is verified. At the same time, it is found that the traditional theoretical model has a relatively larger error. Numerical study also shows that the carcass radial compression stiffness obviously increases with the increase of the ratio of its thickness over its diameter. The numerical model and analysis technology presented in this paper provide an efficient method for the design and analysis of radial compression property of the unbonded flexible pipe radial compression in industry. ©, 2015, Editorial Office of Journal of Harbin Engineering University. All right reserved.