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SAFER, SMARTER, GREENER

SESAM™ PIPELINE

DNV GL, at the forefront of pipeline technology, released the Recommended Practice DNVGL-RP-F105 for Free Spanning Pipelines.

The objective of this Recommended Practice is to provide ra-tional criteria and guidance on fatigue design methods for free spans subjected to environmental loading.

FatFree is used in the design and (re)assessment of submarine pipeline spans, complies fully with the DNVGL-RP-F105

FatFree is a VBA (Visual Basic for Applications) based program with a user-friendly Microsoft Excel spreadsheet interface. (Excel unsupplied)

By using FatFree, the fatigue life due to inline and cross-flow Vortex Induced Vibrations as well as direct wave loading can be calculated, for current and wave induced loads.FatFree comes with a module for performing multiple analyses of free spans.

What FatFree can do for you ■ Helps you make a safe engineering analysis with respect to maximum allowable free span.

■ Helps you decide about the need to correct or intervene a span, by providing you the state-of-the-art analysis tool for free spanning pipelines.

■ Helps save costs related to unnecessary free span correction. ■ Allows longer spans as compared to other codes and standards based on modern limit state principles.

FatFree A professional software for engineering analysis of free spanning pipelines according to the DNV GL Recommended Practice, DNVGL-RP-F105.

DIGITAL SOLUTIONS

DNV GL AS, digital@dnvgl.com, www.dnvgl.com/digital October 2018

Optimal Free Span AssessmentA two level assessment approach has been developed based on the following criteria:

Analysis Level 1: Fatigue criterion using actual span parameters with simplified estimates of frequencies and mode shapes

Analysis Level 2: Fatigue criterion with response quantities from a full FE eigen value analysis

FatFree capabilities comprise: ■ Fatigue life calculations due to in-line VIV response due to currents.

■ Fatigue life calculations due to cross-flow VIV response due to currents.

■ Calculations of von Mises peak stress in in-line and cross-flow directions.

■ Simplified models for preliminary analysis and detailed models for accurate results.

■ FEM based structural analysis results can be integrated and used as input.

■ Results from multiple span analysis can be used to establish the acceptance criteria.

■ Multiple span analysis can be used to study span develop-ment and also perform sensitivity of spans to gaps, trenches, span length, etc.

The analysis features of FatFree represent state-of-the-art technology and the program is unsurpassed for practical applications.

FatFree Current features include: ■ Elegant Current model template to SPECIFY current data as Histograms, Weibull distributions or in terms of Return Period Values.

■ Directionality can be easily modelled by using omnidirectional current or directional current data.

■ User friendly structural modelling to specify pipelines geometric, material and operational data.

■ Updated response models to account for pipe-in-trench effect. ■ Graphical representation of the Response Models. ■ In-built SN curves from DNVGL-RP-C203 for steel pipelines in air, seawater or seawater with corrosion protection, with edit-able options.

■ In-built soil stiffness and soil damping models. ■ Effect of concrete coating. ■ Pull-down menu options to choose Safety Factors. ■ Graphical representation of the damage distribution as a function of direction.

■ Flexibility to provide “User defined” parameters, in all the pull down menus.

■ Extremely short computational time ensuring fast but reliable results.

■ Thoroughly validated, verified and field tested.

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