Freespan Analysis Software

Free Span Analysis software is capable to perform complete free span analysis according to the DNV Recommended Practice RP-F105 “Free Spanning Pipelines”. The aim of the analysis is to define critical allowable pipeline free span lengths along the pipeline route or to check free spans assessed in the pipeline operation by the means of screening checks and detailed fatigue analysis due to vortex induced vibrations (VIV) and direct wave action on the pipeline free span subjected to combined influence of ocean currents and waves.

1. Pipeline Free Spans Screening Analysis, with capability of finding critical allowable span lengths
2. Pipeline Free Spans Detailed Fatigue Analysis, with capability of finding critical allowable span lengths, including IL and CF Response Models and Frequency Domain IL Force Model
3. Pipeline Free Spans Ultimate Limit State (ULS) check, including functional and static and dynamic environmental stresses, with capability of finding critical allowable span lengths
4. Pipeline free spans simple beam buckling check, with capability of finding critical allowable span lengths
5. Definition of pipeline project as a set of pipeline sections with flexible data input and flexible association with independent environmental data sets (ocean current and wave data for screening and fatigue analysis)
6. Flexible input of environmental data sets in the form of ocean current and wave data for screening and fatigue analysis with preprocessing of statical environmental data
7. Structural response analysis according to simplified structural response formula, based on the first natural vibration mode and single isolated span model
8. Soil damping and stiffness calculation according to simplified soil model
9. Configurable analysis report module with plots of important parameters
10. Registered file types FreeSpan Analysis project file (extension fsa) and FreeSpan Report file (extension fsr) that are associated with application during setup and are automatically opened from windows explorer.
11. Export of analysis report in HTML format

FreeSpan analysis input data structure design is based on the division of the offshore pipelines into pipeline sections that represent parts of the pipeline in succession which differ significantly in at least one parameter influencing analysis results.

Input data are further divided, for the sake of problem definition flexibility, into 2 major groups:

• Project (pipeline) Data
• Environmental (currents and waves) Data

That division makes possible to independently define and associate pipeline section and environmental currents and waves data.

Project is the base data entity on the top of the pipeline data hierarchy that contains other data entities. It represents the whole pipeline containing different sections with all parameters needed to perform free span analysis. Project data contain all parameters and choices that define analysis steps and options. Every project consist of arbitrary number of pipeline sections entities. General distinction and criteria for pipeline division into pipeline sections are considerable changes in water depth, seabed soil properties, concrete coating thickness, pipe dimensions etc.

Section data item represents all parameters that define pipeline sections and associated free span analysis parameters.

Environmental data structure contains screening and fatigue data sets that could be of current or wave type. Fatigue data sets contain different data groups depending on the current or wave fatigue data definition. Current and wave fatigue data sets could be of omnidirectional or directional type. Directional fatigue data set comprises of arbitrary directional sectors data sets.

Every project section can have associated up to four defined environmental data set, one of four environmental data set types:
• Screening Current Data Set
• Screening Wave Data Set
• Fatigue Current Data Set
• Fatigue Wave Data Set

Minimal association is with only screening current data set to be able to perform screening analysis without wave velocity influence.

Copyright 2013 - Department of Fluid Mechanics and Computational Engineering