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Home > Version History > What was new in Version 5.3

What was New in Version 5.3

The upgrade to version 5.3 includes several significant improvements and bug fixes. The main changes and enhancements are listed below:

New features:

  • Editing groups content: The list of components included in any Group may be edited by double-clicking the group item from the model browser. Adding components to any group can then be made by selecting the desired components from the Edit Group form. Components which already belong to another group are highlighted so as to prevent any groups data conflict. The Edit Group form makes the definition of groups simpler and clearer. Model components can of course still be moved into or removed from groups by dragging and dropping them in the model browser as within former versions.

  • Updated line component dataform: The line component dataform has been updated to allow defining the segmentation either by setting the number of elements or by specifying a target element's length. The number of elements along the segment is then automatically set based on the target element's length which provides better control over the quality of the mesh. Section split method is also invoked through a single Split method which allows either inserting a single intermediate node along the section or inserting series of intermediate nodes along the section. The external file used to specify the user-defined shape of section is now input straight from the sections table.

  • Display of Line segmentation data: Line segmentation data can display from the Quick Data Access module. Clicking the Quick Data Access button from the tools bar and further selecting the Lines segmentation data item brings up the segmentation data for all line components included in the model. This allows for fast verification and upgrade of segmentation data.

  • Updated Sea&Ground component dataform: The content of the Sea & Ground component is now presented in separate tab-sheets for more clarity. The Physical parameters sheet allows defining new data items such as seawater kinematic viscosity, air density, air kinematic viscosity and the acceleration of gravity.

  • Drag and inertia coefficients: Line segment types feature new data item which allows defining axial and normal drag coefficients in air, and axial and normal added mass coefficients that are not linked to the axial and normal inertia coefficients. Former versions solely allowed to specify added mass coefficients being equal to the inertia coefficient minus one which is only valid for circular cross-sections.

  • Improved import of ISYMOST mesh files: The import of ISYMOST mesh files used to describe truss structures made of beams (.TDL files) has been improved. This allows accounting for bidirectional bending stiffness for beam profiles, import of material properties different from steel properties, and automated setup of connections orientations (beta angles).

  • Display of local axes along lines: Local axes along Line components may be displayed in the 3D View Window upon clicking the Show Local Axes On Lines button located in the tool bar. Local axes would only display in DSS files when showing outputs from a simulations. Local axes allows identifying the orientation of bending axes at any beam element and check torsion along lines.

  • Update of DSK model data through LOG files: The routines used to update the content of DSK model files further to identification of changes made to a LOG file have been enhanced. The routine is now able to handle changes made under the BEAMPRO, BEAMPRO2 and *B2GEN keywords. Flexible line type data describing the cross-sectional data and segmentation of Line components can therefore be updated through the routine.

  • Changes to non-linear vessel hydrostatics: Calculation options used to account for non-linear vessel hydrostatics through coupled analyses have been revised. Non-linear hydrostatic loads can be derived through the hull shape with respect to the undisturbed sea surface or with respect to the actual wetted surface which account for the relative position of the vessel and the wave elevation (the hydrostatic and Froude-Krylov loads instantaneous loads are computed per panel of the mesh, and the hydrodynamic database must only contain the diffraction forces). Non-linear hydrostatic loads can also be calculated for the quasi-static analysis steps only, for the quasi-static analysis steps and upgraded at any time-step, or for the quasi-static analysis steps and upgraded at any sub-iteration within the time-steps. These calculation options can be specified through the NL Loads sheet which is available from the Floater Motion type dataform.

  • Post-processing of frequency-domain analyses: The post-processing routines used to extract internal loads along beam, bar and cable elements from frequency-domain dynamic simulations have been revised to fix shear force and bending moment accuracy issues. The post-processing method now account for the stiffness matrix of the beam element which is combined with the dynamic displacement components instead. This results in greater accuracy in internal loads extracted from frequency-domain dynamic simulations. It must be noted that this change only impacts frequency-domain simulations and that no change was made to the post-processing of time-domain dynamic simulations.

  • Enhanced governing wave search method: New options have been implemented to let you select some governing events to be included in time-domain dynamic simulations based on irregular waves. The governing event drives the way the pseudo-random phases or the individual wave components are determined. The governing event can be either based on maximum wave height or maximum downwards velocity recorded at any selected node. The maximum wave height to be encountered can be controlled through the upper and lower accuracy percentages against the target height. These options can be specified from the Numerical Parameters sheet which is associated with the Calculation Parameters of any analysis.

Changes to Wind Turbine components:

  • Automated update of blades pitch and twist: Blades pitch profile and twist profile are automatically updated as the wind turbine is switched from clockwise rotation to anti-clockwise rotation (or the opposite). A warning message displays as you change from clockwise rotation to anti-clockwise rotation asking whether you wish the blades pitch and twist profiles to be updated. Blades pitch and twist profiles has to be adapted manually when switching from clockwise rotation to anti-clockwise rotation in former versions.

  • Prescribed velocity control mode: The prescribed rotation speed control mode has been activated. Selecting prescribed rotation speed control mode from the Control tabsheet yields a table in which you may define the rotation speed (rpm) function of time (s).

  • Blades and tower point loads: Blades and tower components are now available within the Prescribed Loads components. You may then apply point loads to any node along the tower or the blades. Point loads may include constant loads, incremental loads, lump-mass or variable dynamic loads.

  • Connection to blades and tower: All model components may now be connected to wind turbine blades and tower at any location along the blade or the tower. Wind turbine blades and tower are indeed included in the list of components to which other component would connect. Connecting Rigid Body components that are submitted to some Prescribed Loading for instance allows modelling out-of-balance loads applied to the tower or the blades.

  • Prescribed nacelle orientation: The orientation of the nacelle can be prescribed using Prescribed Displacement components. Yaw rotation may be applied to the nacelle reference point by selecting the control displacement type and further defining the amplitude of yaw along with the initial and final quasi-static steps.

  • Generator self inertia: A new data field has been included in the Power Train tabsheet which allows specifying the inertia of the generator. Inertia of the generator is accounted for with the idling wind turbine condition.

  • Aerodynamic pitch and structural twist along blades: The aerodynamic pitch and structural pitch profiles along blades can now be defined separately. Aerodynamic pitch and structural twist are now presented in two columns within the Blades data table whereas a single pitch data column was available in former versions.

  • Upgraded power train data: The gearbox efficiency used to be defined function of rotational velocity only. It can now also be defined function of torque. Rayleigh structural damping may also be applied to the power train.

  • Generator efficiency tables: The generator efficiency (electrical power over mechanical power ratio) which is defined in the Control data set can be variable function of the mechanical power. The generator efficiency used to be a constant percentage within former versions.

Improvements to the FE engine:

  • Separate Lines convergence check method: The static and dynamic convergence criteria used to be checked for the whole set of elements at once based on the maximum internal loads among all elements included in the analysis. This could yield some accuracy issues when the analysis included very taut lines and other lines experiencing almost zero loads. The convergence criteria can now be checked separately for each line / group of elements which ensures accurate solutions even with lines experiencing significantly different loads values. This feature may be activated through the *OPT_CONV keyword which is to be input in the user-defined keywords area of any analysis. It must be noted that the solution method however still considers the complete set of elements as a whole (complete matrix inversion).

  • Changes to Lump mass loadings: Mass and inertia components are now defined with respect to the local coordinates system of the node to which the lump mass loadings apply. Mass and inertia components used to be defined with respect to the global coordinates system in former versions. The vertical position used to select whether the weight had to be equal to the weight in water or the weight in air now accounts for the instantaneous wave elevation and not solely the undisturbed the surface elevation.

  • Changes to Buoy components: Mass and inertia components are now defined with respect to the local coordinates system of the Buoy component. Mass and inertia components used to be defined with respect to the global coordinates system in former versions. The net buoyancy force now only applies in case the reference node of the Buoy component is actually located below the sea-surface. If the reference node of the Buoy component is located above the sea-surface, the weight of the Buoy component is set equal to the Z-translation mass times the acceleration of gravity.

Bug fixes:

  • Touch-down point results post-processing: Post-processing routines used to extract analysis outputs at the touch-down point might fail in reporting the outputs at the correct TDP location on some instances. This bug has been fixed in this release.

  • Orientation of Rigid Bodies components: The orientation of Rigid Body components might be set incorrectly in case the component the Rigid Body connects to had its own orientation including angle values set to 180 degrees.

  • Deleting several fairleads/hang-off points: Fairleads/hang-off points included in Floater, Rigid Body and Buoy components had to be deleted one by one as deletion of several Fairleads/hang-off points at one time did not work even when several rows were selected from the table.

  • Deleting several contact modelling requests: Contact modelling requests had to be deleted one by one as deletion of several Contact modelling requests at one time did not work even when several rows were selected from the table.

  • Problem within copy/paste of HAWT components: The aerodynamic pitch profiles along blades were not properly duplicated when copying/pasting HAWT model components. Aerodynamic pitch profile data were incorrectly set to all along the blade in the new HAWT model component.