Laying Modeling of Submarine Pipelines Using Contact Elements into a Corotational Formulation

A new finite element formulation to analyze stresses and displacements in submarine pipelines during laying operations is presented in this paper. The method is based on the corotational formulation using Bernoulli nonlinear beam elements to model the large displacements and rotations of the pipeline. The penalty method is used with spring-contact elements to accurately represent the actual boundary conditions on both the stinger and the sea floor. A comparison with a finite element formulation introduced by the authors in a previous paper is presented in order to verify the accuracy and computational effectiveness of the proposed method. A real laying case of an oil transportation submarine pipeline is also presented at the end of the paper to validate the results obtained with the developed formulation.

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Laying Modeling of Submarine Pipelines Using Contact Elements Into a Corotational Formulation

10.1115/imece2001/pvp-25210 ◽

2001 ◽

Author(s):

Cora Martínez ◽

Raúl Goncalves

Keyword(s):

Finite Element ◽

Boundary Conditions ◽

Finite Element Formulation ◽

Element Formulation ◽

Corotational Formulation ◽

Sea Floor ◽

Displacement Boundary ◽

Convergence Process ◽

S Curve ◽

Spring Contact

Abstract A new finite element formulation to analyze stresses and displacements in submarine pipelines during laying operations is presented in this paper. The method is based on the corotational formulation using Bernoulli non-linear beam elements to model the large displacements and rotations of the pipeline. The penalty method is used with spring-contact elements to accurately represent the actual boundary conditions. During the lay barge installation, the pipe rolls over the barge ramp and slides over the stinger before reaching the sea floor. The barge stinger is a ramp over floating supports that holds the pipeline in such a way that the pipe adopts an S-curve during the laying process. Since contact elements allow the pipeline to separate from the stinger at those points where the contact is lost, introducing these elements into the analysis makes it possible to accurately model the actual boundary conditions on the stinger. In addition, the use of contact elements allows the pipe to reach the sea floor at all those points, which naturally require this condition without imposing any displacement boundary condition during the convergence process. A real laying case of an oil transportation submarine pipeline is presented at the end of the paper to validate the results obtained with the developed formulation. A comparison with a finite element formulation introduced by the authors in a previous paper is also presented in order to verify the accuracy and computational effectiveness of the proposed method.

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Nonlinear 3D Finite Element Formulation for the Analysis of Submarine Pipelines During Laying Operations

Recent Advances in Solids and Structures ◽

10.1115/imece2002-32295 ◽

2002 ◽

Cited By ~ 1

Author(s):

Marco Ciaccia ◽

Cora Marti´nez ◽

Raul Goncalves

Keyword(s):

Finite Element ◽

Boundary Conditions ◽

Three Dimensional ◽

Finite Element Formulation ◽

Element Formulation ◽

Corotational Formulation ◽

Sea Floor ◽

Convergence Process ◽

Internal Forces ◽

Lift Off

A new three-dimensional formulation using the finite element method is presented in this paper to analyze stresses and displacements of submarine pipelines during laying operations. The method is based on the Corotational formulation using Bernoulli nonlinear beam elements of constant cross-section. The problem is modeled in such a way that the actual boundary conditions are all taken into account. The pipe rolls over the barge ramp, passes through a tensioner and slides over the stinger before reaching the sea floor. The stinger is modeled introducing gap elements into the analysis, which makes possible to model exactly the actual boundary conditions, since these elements allow the pipeline to separate from the stinger naturally as required. This fact improves noticeably the calculation of the internal forces in the supported length of the pipe as well as in the region close to the lift off point. Additionally, using gap elements allows the pipe to reach the sea floor in all that points that naturally require this condition; therefore it is possible to drive the pipeline to reach the sea floor without imposing any displacement during the convergence process, which can generate instability problems. In addition to the applied tension at the barge, the buoyancy and the weight of the pipe, lateral forces induced by marine currents are also considered in the analysis. Numerical examples are provided in order to verify the accuracy and computational effectiveness of the developed method in comparison with the finite element formulation developed by the authors in previous works.

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