Overview
Why a new tool?
Recognising that users have experienced considerable challenges in using LR’s RulesCalc Offshore application, Lloyd’s Register (LR) has re-evaluated its short‑term strategy for Offshore Rules software and decided on a new approach. The new LR Offshore Rules Support is a spreadsheet solution to assess whether individual scantlings comply with LR’s Offshore Rules. The spreadsheet has been thoroughly validated and is stable and accurate.
Applicability
LR Offshore Rules Support checks compliance with the 2018 Rules and can also be used for the 2016 and 2017 Rules. The tool covers the following types of floating offshore structures:
- New construction FPSO
- FPSO conversion
- FLNG
Features
What does it do?
The following regions of the hull structure are included:
- Fore end
- Cargo hold region
- Machinery space
- Aft end
LR Offshore Rules Support covers Rule conditions for the following operational conditions: -
- Normal on-site operation
- Transit
- Inspection/maintenance
- Flooding
What is the scope of the assessment?
Currently the tool only covers the following longitudinal structural elements:
- Plate
- Stiffener
- Primary Structure Member (PSM)
The tool covers the assessments of:
- Minimum thickness and section modulus
- Required thickness corresponding to the Rule design pressure
- Required section modulus and shear capacity corresponding to the Rule design pressure
- Buckling assessment by LR Buckle Method
- Bottom slamming and bow impact
A number of features have been incorporated into the software based on feedback from designers and builders, including:
- Three different approaches for specifying the site‑specific loads (EFFs/DLCFs); (i) selecting standard Rule values, (ii) importing loads from ShipRight Offshore; and (iii) manual entry
- Specify separate corrosion margins on webs and flanges of primary structural members
- Standard stiffener library feature
- Inclusion of Rule references and intermediate calculations to improve understanding of non‑compliances
- Enhanced responsiveness through partial recalculation
What next?
The next phase of development starts in November 2018 and will deliver both improved usability, by adding a graphic user interface and reporting tools, and extend the scope of the calculations to include:
- Hull girder bending capacity
- Ultimate strength
- Direct shear flow
- Hull girder shear capacity