1. SIMA 4.8.0 Release Notes

1.1. New Features - SIMO

Description

Reference

Line characteristics as result

It is now possible to choose to store the line characteristics table for Catenary Lines as a result from static analysis.

1.2. New Features - RIFLEX

Description Reference

Fibre Rope Creation Wizard

New wizard available in RIFLEX when creating Fibre Rope cross section. See new and noteworthy for more details

issue#165

New Chain Cross Section

New cross section type Chain available. See new and noteworthy for more details

issue#145

Marine Growth input for NORSOK N-003

In the Marine Growth component it is now possible to import values defined in NORSOK N-003 standard for 59-72 degree North. See Marine Growth component editor.

issue#165

Storage of the touch down point location

Storage of the touch down point (TDP) location is now available.

The following results is stored

  • seafloor/soil contact results for the TDP-region

  • arclength from super node 1 on the line

  • global coordinate x- and y of the TDP point

Storage of TDP results may be specified in the new Bottom Contact storage section of Dynamic Calculation Parameters in the UI or in the data group BOTTOM CONTACT STORAGE in the input file.

The results are written to the key-file and bin-file

  • key_<prefix>_botres.txt

  • <prefix>_botres.bin

issue#60

User defined skew wake factor

A user defined skew wake parameter, K, is added to the skewed inflow correction in the BEM formulation for wind turbines.

issue#105

Input changes of storage of seafloor/soil contact results

The specification of seafloor contact storage is removed from the data group FORCE RESPONSE STORAGE. Storage of seafloor/soil contact must be specified in detail in the data group BOTTOM CONTACT STORAGE.

The results are written to the key-file and bin-files:

  • key_<prefix>_botres.txt

  • <prefix>_botres.bin

The key-file and bin-file name is unchanged compared to previous versions.

srvissues/issue#1046

Stiffness proportional Rayleigh damping

For the three bisymmetric cross-sections: Double-symmetric cross-section and General cross-section, separate damping parameters may be specified for bending around local y- and z axis.

SRV-2087

Wind files from TurbSim (OpenFAST version 3.2.0 and later)

Wind fields generated with TurbSim, integrated with OpenFAST version 3.2.0 and later, can now be used in simulations.

The clockwise parameter was removed in TurbSim (OpenFAST version 3.2.0). If this parameter is not found in the .sum-file it is now assumed that the parameter is False, i.e. the file follows the left hand convention which is the case for files generated by TurbSim 3.2.0 and later.

SRV-2108

Fibre rope initial elongation

Fibre rope segments have an initial elongation given by the input historic highest mean tension (Tmax). This gives an initial stress-free length that is larger than the modelled distance between the end nodes. This can cause convergence problems if the elongation is applied before other loads cause deflections from the straight line between the end nodes. This has so far been the case as the elongation has been applied at the start of the static analysis.

The initial elongation is now applied in the same way as user-defined stress-free segment lengths, i. e. gradually during a load group. If Initially pre-stressed segments is specified, the fibre rope elongation will be applied in this load group together with any stress-free segment lengths specified by the user. Otherwise, the elongation will be automatically applied in the first load group.

SRV-2117

Max tension of Fibre rope segments

Key results are presented for all segments with Fibre rope cross-sections in the file <prefix>_fibres.asc:

  • maximum tension at the end of the static analysis

  • input maximum historical tension

It is possible to double click the file in the SIMA navigator to inspect visually. The result will also be available in the post processor

sesam/issue#13

Added missing signals to Bladed style controller

AVRSwap record 14 (measured shaft power) and 23 (measured generator torque) are added to controller input

sesam#9

Fibre rope original curve

It is no longer necessary to specify the original curve for fibre rope cross sections. The original curve is not used in the analyses.

sima/issue#147 (DNV 00199406)

Specified stress-free segment length

Time domain, eigenvalue and frequency domain VIV analyses will now check that specified stress-free segment lengths have been applied during the preceding static analysis.

If the specified stress-free segment length has not been applied and the relative difference is more than 0.001, the program will exit with an error message. A warning will be given if the relative difference is more than 0.00001.

SRV-2117

Simplified Reference frame assignment

New action in Reference Frame editor added to assign given reference frame to selected super nodes while keeping their global position

issue#132

SN-curve thickness correction input changed

The reference thickness, TREF, and the exponent, KEXP, for thickness correction must either both be zero, no thickness correction, or both positive, thickness correction included. KEXP was previously dummy if TREF was zero.

RIFLEX and VIVANA input files where only one of these is zero must be modified.

issue#13

1.3. New Features - Other

Description

Reference

Improved condition result presentation with simplified post processing

Condition result now has a new view for easier inspection and interactive post processing There are three default views: * Plot * Statistics * Power Spectrum

It is also possible to select a time window and filter the time series. See Options tab. This has been influenced by the open source DNV tool QATS, which also can be used to post process SIMA results outside of SIMA

The signals has been removed from the navigator tree, which has added performance benefits

See New and Noteworthy for details

sesam#1

Improved video export

Exporting 3D animation of analysis results to video is now improved. You can point to an FFMPEG installation in SIMA preferences to create video from still frames directly. See documentation for details.

sesam#47

View from side in 3D

Added view from side in context menu in 3D view

sesam#62

Tighter integration of Python in Workflow

A new operation in workflow is added called "Python Program", which makes it easier to run external Python scripts. See example Help→Examples→Workflow→Python in Workflow

issue#63

Enable open workspace from .sima file

It is now possible to open the workspace directly from double clicking the .sima-file in Windows. The file ending must be associated with SIMA manually in Windows.

sesam#56

Improved documentation for Metocean Task

Fixed some missing figures and added more documentation in help

issue#133

Context menu improvements for "New" entry

"New" menu has been improved to make large entries more easily navigable. The different items are now grouped. The new menu is also added in post processor and workflow diagrams

issue#131

2. Resolved Issues

2.1. Resolved Issues - SIMO

Description

Reference

Correction to Fluctuating Wind

The fluctuating components of wind speed is no longer scaled with the mean wind speed profile.

Expect changes in fluctuating wind speed in main direction when wind speed is calculated at elevations other than the wind reference height. This will typically be the case when using wind coefficients on Slender Elements or when using Quadratic Wind Coefficients with a reference height different to the wind reference height.

Longstanding error.

API Wind Spectrum Formula

The API wind spectrum formula has been corrected to use the mean wind speed at height \(z\) instead of mean wind speed at reference height.

Expect changes in fluctuating wind speed in main direction when wind speed is calculated at elevations other than the wind reference height. This will typically be the case when using wind coefficients on Slender Elements or when using Quadratic Wind Coefficients with a reference height different to the wind reference height.

Longstanding error.

Moment Coupling Damping Coefficients

Unit conversion scaling factor used in simulations for Moment Coupling’s values Positive Damping and Negative Damping has been corrected. Expect change in results for models using non-zero values for these values.

#25

Removed Catenary Line Value XWinch

The input value XWinch has been removed from Catenary Lines.

SRV-1910

Force calculation method for Wave Drift Damping from SIF file fixed

Wrong force calculation method was selected for wave drift damping from SIF file. Corrected to "Body velocity relative to current"

issue#97

Wave drift damping forces are now calculated based on low-frequency velocity

For body type 1 (6-DOF time domain in SIMA), wave drift damping forces used to be calculated based on total velocity. Now, it is calculated based on low-frequency velocity.

SRV-2138

2.2. Resolved Issues - RIFLEX

Description Reference

Bodies with Time Dependent Volume Mass

Using bodies with Time Dependent Volume Mass in RIFLEX models would previously cause simulations to fail. This issue has now been resolved.

#17

Incorrect heading in print of FEM data

The order of external diameter and hydrodynamic diameter was switched and incorrect unit was reported on drag coefficients in <prefix>_eledat.asc.

This is corrected.

sima/issue#38

User defined elements

The user defined elements could not be used if any boundary conditions were referenced to a skew coordinate system.

This is corrected.

issue#38

Kinematics key file

Incorrect super node ids was written to the key-file.

Error since SIMA 4.6 / Riflex 4.26 (June 2023)

issue#14

Fixed failing automatic initial position for Super Node

When initial line length is shorter then the actual end distance the automatic positioning failed. This has been fixed

sesam#31

Incorrect display of pre-bent line type

Display of pre-bent line type was incorrect in model view. This is corrected. Long standing error.

#34

2.3. Resolved Issues - Other

Description

Reference

Fixed clipboard issues

Fixed several small issues when exporting/importing to and from clipboard in tables.

sesam#65

Add missing fields in the customized table

In some editors, such as Point Fender in SIMO, not all of the available fields where present for the customize table operation. These are now added.

sesam#64

Fixed WAMIT frc import scaling

Fixed incorrect scaling of Linear Damping matrix when importing from WAMIT frc

issue#48

Removed unused percentile in code check

The percentile in the code check editor was not used and is removed. The percentile is in reality calculated based on time duration of time series, number of peaks and return period.

issue#302

3. Known Issues

3.1. Known Issues - SIMO

Description Reference

The wave drift damping force from Newmans method available as a SIMA result is erroneous. The error only affects reported forces, not the simulated responses.

SRV-2125

Wave Methods Visualization and Combined is deprecated and will be removed in a future release of SIMA.

The Nonlinear Buoyancy Correction feature is deprecated and will be removed in a future release of SIMA. Please use Nonlinear Hydrostatic Stiffness instead.

SRV-1609

The old "Version 4.0" formulation for thrusters and DP control systems are deprecated and will be removed in a future version of SIMA.

SRV-1912

3.2. Known Issues - RIFLEX

Description Reference

Mass proportional damping for general cross section (CRS7): The mass proportional damping is applied in the local system and not at the eccentric mass center. Note that use of mass proportional damping is not recommended as this will damp rigid body motions.

SRV-2093

  • VIVANA analysis with CF and IL loading without IL added mass iterations *

Frequency domain VIV with cross-flow and in-line loading calculated without added mass iteration for in-line response frequencies gives zero in-line response. This is incorrect and will be corrected in the future.

Normally, the in-line added mass is adjusted to obtain an in-line eigenfrequency that is twice the cross-flow response frequency. This is done for all cross-flow response frequencies. This is time-consuming and is not always successful.

This in-line added mass iteration is skipped if the cross-flow added mass property is given for a single nondimensional frequency for all segments. The in-line response frequency will be twice the cross-flow response frequency, but will not be an eigenfrequency. The in-line response is therefore expected to be small, but should not be zero.

SRV-2145

3.3. Known Issues - Other

Description Reference

Some users have experienced font issues in the report and/or the plots after a windows 10 update. A workaround is to change the font for the plots.

SIMA-8668

SIMA crashes in some cases when screen-saver starts or an external screen is connected and SIMA window is opened. If this occurs the user should test alternative graphics drivers in settings and turn of screen-saver.

SIMA-7090