A Simplified Numerical Method for the Design and Analysis of FPSO Platform Brackets Subjected to Operational Conditions

Abstract

The present work develops a simplified computational methodology to predict brackets’ mechanical behavior to support mooring systems’ fairleads under maximum environmental loads. The methodology consists of estimating environmental loads in Campos’s basin (Brazil) using standards available in the literature and applying them to determine the stress distribution in the brackets’ solid domain using a code based on the Finite Element Method. The brackets studied here are composed of AH36 steel plates. Six different geometric configurations for the brackets considering thinner plates than those ordinarily employed in the existent brackets of the P-66 Petrobras oil production platform were studied. Theoretical recommendations about geometric configurations to reduce the von Mises maximum stress in brackets’ plates were determined in the light of constructal design. The results proved the importance of the geometric investigation in this problem. For instance, for the accidental limit state (ALS) the best configuration leads to a mechanical performance two times superior to that reached for the worst one, which had a maximum stress superior to the yielding limit. Moreover, the best designs for the superior and inferior brackets in the ALS have different configurations.

Keywords

• mooring systems
• brackets
• mechanical behavior
• design methods
• constructal design
• geometrical optimization