SIMA 5.2.0 Release Notes

The element force-transformation result now also reports the element-end moments in the global system, alongside the existing global forces. For each transformed beam element end, three new signals are available: "Moment in global x/y/z-direction". Bar elements (axial force only) are unaffected.

The tension-torsion coupling terms in the stiffness matrix have been corrected. Only insignificant changes are expected in the results. A significant speed-up with regards to convergence during iterations has been observed.

Corrected stiffness input for the coupled axial-torsion strain model. Only constant axial/torsion stiffness is now allowed for coupled axial-torsion strain mode.

Previously, the transfer functions were extrapolated outside the range for which they were specified. This linear extrapolation could produce large values outside the specified range, especially at high frequencies. These values could be avoided by adding a pair of frequencies with zero values before and after the original range.

This is now changed:

This change may affect the results.

When both ends of a line have Automatic Initial Position, the first end (end1) acts as the anchor with initial=static, and end2 computes its initial position relative to the anchor. This guarantees that the initial endpoint distance always matches the stress-free line length.

When RIFLEX static or dynamic analysis fails, there are now better suggestions for where the error has occured. 3D graphics will also show the first node that has failed in a visual way

Time-domain VIV loads due to wind may be specified for thin-walled pipe cross sections, axisymmetric cross sections, and coupled axial-torsion.

Bodies in RIFLEX models can now act as a frame of reference for Reference Frames and supernodes.

Importing a GeniE (Sesam FEM) model into RIFLEX now reads General Beam Element Data (GBEAMG cards), so sections defined by general beam properties are imported as RIFLEX general cross sections.

Drag amplification (DAF-MEAN and DAF-Vandiver) curves are stored in the .mpf file.

Additional information about seafloor contact specification is written to stamod.res. Information about seafloor contact element and relation to segment ends is added.

The water density can vary with the water depth.

This is specified in Model → Location → Water depth.

Marine growth can now be applied to cross sections with a MacCamy-Fuchs load.

Right-click in the 3D view and toggle Show Internal Nodes; this now supports static and dynamic results.

An example with shared mooring farms with INO WINDMOOR 12 MW reference floating offshore wind turbines (FOWTs) at a water depth of 350 m has been added. Each FOWT is connected to three anchor lines and a shared line.

FOWT grid example

The names of result time series for bodies have been improved for better clarity. At the same time, simulation performance has been improved because SIMO no longer writes redundant data to disk during a simulation. The new result names mean that any post processor or workflow that uses signal selection for body results must be updated manually. To continue using the old result names, you can uncheck the Use new result structure checkbox in the storage section of Dynamic Calculation. Old models are migrated with this option unchecked, so any post processors and workflows created for the model continue to work. Note, however, that this option may be removed in a future release.

Using Import wizard → SIMO → Sesam FEM file, you can now import a GeniE FEM file as SIMO Slender Elements.

The line profile and tension distribution for catenary lines are now available as static results.

sre --import file=<file.sif> configuration=<config.json> now accepts an optional JSON config that mirrors the import wizard: merge into an existing task/body, and set wave-drift (COMBINED/MEAN/HORIZONTAL), QTF (ANY/DIFF/SUM/NONE) and retardation options. Without it, behaviour is unchanged. You can use the import wizard to configure and export the JSON to the clipboard.

In dynamic calculation parameters (Storage) the WASIM result export is renamed to Sesam result export, as this file can be used by other parts of Sesam - not only WASIM.

Surface proximity and direction-dependent loss can now be specified independently.

Right-click in the 3D view and toggle Show internal nodes to see the effect on SIMO Slender Elements.

Opt-in usage telemetry has been added for DNV customers.

Tables can now exchange data with any tab-separated source (e.g. Excel) by column name instead of column position. New menu entries:

The SIMA status dialog now uses a more linear layout for better readability.

A String variable can now be marked as Structured. When enabled, its value is interpreted as JSON and exposed to the scripting engine as a JavaScript object instead of a plain string, so scripts can read nested properties directly. Invalid JSON is reported as a validation error on the variable.

SIMA now provides many more relevant help links in the editors.

A Body and Infrastructure Body can now hold a list of native Shapes (Block, Cylinder, Curved Plate, Geometry), each with its own pose relative to the body.

Right-click the body in the navigator and choose New, then the selected shape.

Support for the HSF 3D graphics file format is ending soon, but conversion to OBJ file is available inside SIMA.

Right-click a body in the 3D view and choose Convert to OBJ file.

Right-click in the 3D view and press Show local Axis to toggle the display of local element axes.

Table columns can now be rearranged by dragging their headers or from the Customize table dialog. The column order and width are remembered per table, so your layout is restored the next time you open the editor.

You can now vary a model reference across the runs of a condition set — e.g. run the same analysis once per cross section by switching the referenced object for each condition. Previously this was only possible in workflow condition runs.

When second-order kinematics was used in combination with the 'Morison partly submerged' load model, the dynamic pressure acting axially on element ends was erroneously set to zero. Now, linear dynamic pressure is applied on the element ends. Note that a second-order correction to the dynamic pressure should ideally be used, but this is currently not implemented.

If a model has no support vessel but the simulation is specified with generated motion, the analysis will now continue for both regular and irregular waves. The generated motion will be set to none (i.e. no motion).

Polyester tension capacity (MBL) was computed with a diameter unit error (~10 kN instead of ~257 kN for a 50 mm rope). Steel wire axial stiffness EA was 100× too low. Both corrected.

The tension capacity was not correctly calculated. This is now corrected.

The simulation time step in regular analysis will now be consistent with the time step used in pre-generating the wave kinematics and hydrodynamic loads for bodies. Previously, the pre-generation time step was not always an integer number of simulation time steps. This could lead to inaccurate Simo body loads in the simulation. Support vessels are currently not allowed in simulations with regular waves and bodies. No change for simulations with irregular waves.

A leading forward slash is now valid for all filepaths and filenames (Linux). Previously, this was only supported for a selection of filepaths and filenames.

Example: /home/user/documents/file.txt

The visualization of the 3D bottom was not correct for angles different from zero. This is now corrected.

The Pv, Mt, base shear load, and base moment damping fields have been removed from the PISA soil type. These fields had no effect on the analysis as the underlying physics was not implemented.

The Local Element Axis global coordinates were wrong on RIFLEX export when a reference frame was connected to another reference frame.

The 3D view of a flat bottom with a non-zero angle did not match the generated input: the bottom was rotated about its offset position instead of about x = 0. This is now corrected.

Updated documentation:

The internal fluid volume velocity will only affect the calculation of true wall force and stresses. The input fluid volume velocity (length^3/time) was used in the calculations instead of the fluid velocity (length/time). Also, the contribution was incorrect if inconsistent units were used.

This has been corrected. Note that this is a standalone only feature and not relevant through Sima.

Time domain VIV loads may be specified for the Coupled Axial-Torsion cross sections, but the loads were not applied in the analysis.

When coupled retardation functions between more than two bodies was present in a SIMO body system, only one of the body to body interactions was included. Thus, the forces on a body was influenced by the velocity of the body itself in addition to the velocity of one of the other bodies in the system, but neglecting all other bodies. As a consequence, interaction between two bodies was handled correctly, but interaction between three or more bodies was wrong. This has now been corrected, and all interactions between bodies in a system are included.

The plot in the Environment editor previously used the incorrect formula when showing the Ochi-Hubble wave spectrum. It used \(\Gamma \left( \lambda - 1 \right)\) as denominator instead of \(\Gamma \left( \lambda \right)\), giving a ~2× swell peak and inflated Hs. This is now corrected to match the formula used during the simulation.

The error was in the editor plot only; simulations were not affected.

The force from the new Linear Hydrostatics body force model has been added to static results.

Fixed swapped RAO phases, converted all body matrices (mass, added mass, damping) to the SIMO frame, and placed the body origin at the waterline (Lpp/2) so the centre of gravity imports correctly and aligns with WAMIT bodies.

Previously moments applied to a body from a bumper coupling was calculated incorrectly. This has now been resolved. The error was most prominent when the distance from body origin to the bumper contact point was large.

Previously, when SIMA display units were set to non-SI, Excel exports would show non-SI unit labels, creating a mismatch. Excel export currently only supports SI units, and this is now reflected in the labels.

Flickering animations and problems rotating the scene with the right mouse button are now resolved.

Specified linear drag coefficients will be ignored in the analyses for elements with the partly submerged load type.