Interface

The Interface operates under Windows OS and handles all input to the finite element program as well as the upheaval buckling and plot module. It also facilitates display and printing of analysis results in graphical and tabular formats. Many projects can be set up and accessed concurrently by the interface.

Some of the major features are:

• Seabed
  • Seabed information in the form of seabed elevation vs KP or UTM format may be imported, verified, edited and interpolated for use in the stress analysis.
  • Seabed data can be based on pre-lay survey, post-lay survey, post-trenching survey, or as-built (backfilled) survey information.
  • Seabed data can be interpolated using a cubic spline method to increase the number of seabed/pipeline nodes.
• Pipeline
  • Pipeline data can be entered manually or accessed dynamically from a database (e.g. containing pipeline properties, sizes, engineering parameters, coating types and grades, etc.)
  • Regular pipe joints with different stiffness properties to the pipeline can be automatically included.
• Soil
  • Soil properties can be varied along the pipeline route. If route specific data for soil density, strength, friction factors, etc. is not available, properties may be selected from the built-in database of generic soil types. Undisturbed or disturbed soil conditions (e.g. dredged or jet-trenched) can be selected.
• Loads
  • Regularly spaced point loads (e.g. anodes), uniform loads (e.g. soil cover download, or current loads) and prescribed nodal displacements/ loads (e.g. trenching roller height) can be easily specified.
  • Pipelay tension can be varied along the route using the output from a pipelay analysis program.
  • Hydrotest pressures, operational pressures, and temperature variations may all be introduced into the appropriate load cases (empty, water filled, hydrotest, operational, back-filled).
  • Analyses
  • Different load stages can be analysed (empty, waterfilled, hydrotest and operational). Restart facility allowing to restart from any state.
  • Pipeline stresses/strains can be calculated assuming a pipe profile based on top-of-pipe survey data.
  • Analyses for both long lengths (e.g. 20 km) or shorter lengths (e.g. 200 m) may be run from the same data.
  • Upheaval buckling checks may be made using the seabed profile, the calculated pipe profile, or the surveyed pipe profile. Required download and cover depths are calculated along with estimates of rock dump quantities.
• Post-processing
  • Automatic code check against various codes may be selected. Currently available codes are: DnV (1981), Lloyds (1989), BS 8010 (1993) and DNV2000 OS-F101. Areas of non-conformity are flagged.
  • Calculated span lengths and heights may be plotted. Corrective measures may be designed using the Rectifier module.
  • Span check to Vortex Induced Vibration (VIV) can also be performed using the DNV 1981 or the latest DNV RP-F105 standards.
• Output
  • Advanced Viewer allowing to plot up to 10 results (pipeline elevation, internal forces, stresses, strains, soil reaction, …) of up to 6 analyses at the same time. This allows to create comparison charts between different analyses (empty, waterfilled, …).
  • Printed copy of all plots and all input and output data can be produced. Possibility to produce Word file with a summary of all the inputs using the Report Utility.
• Rectification works may be designed by interactively forming cutlines for dredging which satisfy the designated code, or alternatively inserting pre- or post-lay supports. The required seabed elevation profile co-ordinates and support information may then be exported for construction works.