Flexible pipes and umbilical cables project contribution: CAD tools and macro-element model.

Author(s)

Rodrigo Provasi

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Escola Politécnica (EP/BC)
• Defense date: 2012-12-10

Examining board members

Clóvis de Arruda Martins; Ricardo Nakamura; Celso Pupo Pesce; Rafael Loureiro Tanaka; Murilo Augusto Vaz

• Advisor: Clóvis de Arruda Martins

Abstract

The offshore industry is in constant evolution due to the need of reaching new oil fields in increasingly water depths. In this scenario, not only new types of platforms are being designed, but also new types of flexible pipes and new umbilical cable configurations. The greatest difficulty to generate a new concept for a riser is to determine if it is viable or not. Flexible pipes and umbilical cables are complicated to model, due to the interactions between their layers, and to design, due to the great variety of components and possible arrangements. The design of those elements is based on the functions they are intended to perform, leading to the elements that will be selected. The process consists on defining the cable features and selecting the elements that will compose it. The process should take into account the desired structural characteristics and must respect constraints defined in the project. Aiming to turn the conception of these cables into a less laborious process, this work proposes Computer Aided Design (CAD) software, as well an internal mechanic model to deal with the layer interaction. The CAD tool proposed in this work differs from the others by making the cable definition and functions easier. It also includes tools for verification of the cable using a 3D model. It makes possible to the user to create a totally new configuration based on a predefined component library. The software also has a tri-dimensional visualization module, which makes the verification of certain errors attached to the project of such cables, as well enables the visualization of results from the model. Another possibility that the CAD offers is the use of the two and three-dimensional modules as pre- and post processors for other models, not only the one proposed here. This greatly increases its usage possibilities. It is also proposed a finite element model with custom-made elements, called here macro-elements. In this modeling, the elements are described with more details, taking into account the characteristics of the targeted physical elements, minimizing the number of the necessary elements to describe the problem as a whole. With this kind of approach, one intends to utilize all the potentialities from both numerical models, such as the relaxation of certain hypothesis, and analytical models, bundling into the mathematical model the physical characteristics of the element. It is proposed in this work cylindrical elements for sheaths and equivalent tubes, tendon elements and contact and connection elements. (AU)

• FAPESP's process: 06/06281-8 - Project of flexible pipes and umbilical handling
• Grantee: Rodrigo Provasi Correia
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)