09-10-2014, 04:07 PM
Static and dynamic behaviour of a submarine pipeline during installation has been studied. The pipeline is modelled as a beam partially resting on a n elastic foundation with a discontinuous foundation modulus and analyzed by nonlinear finite element method as proposed by Schmidt. Laybarge end of the pipeline is lifted and load is applied in increments to obtain static configuration and bending moment distribution by an incremental procedure together with Newton-Raphson method. A convergence study is carried out to select optimum number of finite elements to ensure faster convergence and accuracy of results. Effects of tension applied at the laybarge, ocean depth and foundation modulus on the static configuration and bending moment distribution are studied. Stiffness matrix as obtained from static analysis together with a lumped mass matrix has been used to deter- mine natural frequencies and mode shapes. Response of the pipeline to a sinusoidal heave excitation is obtained. Effect of heave period on the forced response is studied. The present study indicates that appl