Session: 03-06-01 Composite Material Design and Modelling

Submission Number: 180609

Methodology for Numerical Verification of Composite Patch Repair on Corroded Steel FPSO Deck: a Case Study 

Cold repairs, such as composite patches, are being investigated to restore strength and stiffness of corroded steel plates in offshore units, as they provide a non-intrusive solution. One of the barriers to this type of repair is the lack of current standard. The StrengthBond Offshore (SBO) Joint Industry Project aimed to develop methodologies for certifying composite patch repairs, and in particular the numerical verification.

In this project, an extensive experimental test campaign coupled with numerical simulations was performed on a simplified patch with a scarf in only one direction. Numerical simulations of such steel-composite joint can be quite complex. The numerical approach here was based on Cohesive Zone Model (CZM), at several interfaces within the composite patch. This model was designed to be as representative as possible of the tests. While the simulations with fine meshing were able to correctly depict the behaviour of the composite patch, a model simplification was needed to industrialize such approach due to time constraints.

Thus, the first part of the present study focuses on simplification of the SBO specimens’ model to reduce the pre-processing and computation time. Subsequently, the entire numerical methodology for certifying such repairs is detailed and applied on a case study. A 3-hold model was elaborated with and without repair to investigate the impact on adjacent structures as well as obtaining local loads on the patch. These loads are then transferred to a local model to ensure it sustains the rule loads.

Presenting Author: Maxime Deydier Bureau Veritas

Presenting Author Biography: Maxime Deydier holds a MSc in Materials and Maritime Engineering. He has been part of Bureau Veritas research's department since 2021, in the composite materials section. He focuses on composite propellers as well as composite to steel joint, mainly numerical calculations.

Authors:

Maxime Deydier Bureau Veritas
Jean-Christophe Petiteau Bureau Veritas
Stéphane Paboeuf Bureau Veritas