Umbilical analysis

In this DNV GL Tech-talk webinar, we will demonstrate a highly efficient fatigue analysis methodology using Sesam’s cross-section umbilical analysis tool Helica, which considers stick-slip behaviour in complex cross-sections with helix elements. In the webinar, validation of the applied methodology will be presented, as well as a description of how the tool interacts with commonly used global analysis software. An example will be run to demonstrate the efficiency of stress and fatigue damage calculations using Helica. Accurate evaluation of local stresses in complex cross-sections, e.g. of subsea umbilicals and flexible pipes, subjected to extreme and fatigue loading, is a challenge to the industry.

Fatigue of cross-section components such as helix tensile armors and steel tubes is a critical design issue for dynamic umbilicals and flexible pipes. Fatigue analyses with finite element (FE) tools is computationally demanding and require simplifications for practical use. Global responses such as tension and curvature are needed from global load effect analyses for the cross section fatigue analyses. The global responses need to be prepared and presented in a simplified way for cross-section fatigue analyses using FE tools. Helica reads time series of tension and curvature from the global riser/umbilical analyses and calculates time series of stresses in the various components in the cross section. Helica enables consistency between the global load effect analyses and the local cross-section analyses in addition to consistent treatment of the stick-slip behaviour of the cross section. Fatigue damage along a riser/umbilical from a full one-hour simulation is calculated in minutes with Helica.

The webinar will give you an introduction to the following topics:

• The importance of accurate evaluation of local stresses in complex cross-sections
• The challenge with commonly used tools for fatigue analyses
• What is Helica?
• The methodology applied and full-scale test validation
• Interaction with other commonly used software
• Computational efficiency

Learning objectives:

• Learn how to run efficient and consistent fatigue analyses
• Introduction to the software Helica, what it is and what it can be used for
• Learn how Helica fits in and interacts with other software