ShipMo3D Tutorials - Dynamic Systems Analysis Ltd.
Contents
1. Figure 43 The SeakeepRegular application s pane highlighting how to specify the discrete ship speeds relative sea directions and wave frequencies for which RAOs will be computed t ShipMo3D produces a report of the RAO amplitudes and phases for all 6 degrees of freedom amp In the Save Run and Viewing of Results section click View Output to see the report x The RAO amplitudes and phases relative to the regular wave s phase are found after the following line of text Motions in Regular Waves t The resulting RAOs can also be represented graphically amp In the Save Run and Viewing of Results section of the SeakeepRegular pane click Plot MotionRAQ t n the newly opened Plot Motion RAOs pane the reader can select a ship speed and sea direction and view corresponding plots of the RAOs of the square box in all 6 DOFs as shown in Figure 44 47 Tutorial 8 Computing RAOs ShipMo3D Tutorials File Edit Application Run Output Plot Help Project PanelHull RadDif BuildShip SeakeepRegular Plot Motion RAOs a Box hull analysis Motion RAOs speed 0 m s sea direction 45 deg 0 8 Title Line 1 Box hull analysis o D o e Line 2 Motion RAOs speed 0 m s sea dii Ship speed m s Sea dir deg Surge RAO n l a e e N h c Sway RAO n a o Graph columns e iy Surge 0 5 1 0 12 3 z 0 5 1 0 1 5 2 0 Wave frequency w rad s Wave freq2. ShipMo3D 2014 Tutorials January 22 2015 Copyright 2015 Dynamic Systems Analysis Ltd Dynamic Systems Analysis Ltd 101 19 Dallas Road Victoria BC Canada V8V5A6 phone 1 250 483 7207 Dynamic Systems Analysis Ltd Halifax office 201 3600 Kempt Road Halifax NS Canada B3K4X8 phone 1 902 407 3722 ShipMo3D support support dsa lItd ca DYNAMIC SYSTEMS ANALYSIS Contents Introduction Tutorial 1 Creating a new ShipMo3D project Tutorial 2 Fundamental vessel parameters Tutorial 3 Defining hull geometry using hull lines Tutorial 4 Defining hull geometry with an existing mesh Tutorial 5 Fixing a poorly conditioned mesh Tutorial 6 Computing wave radiation and excitation Tutorial 7 The BuildShip application Tutorial 8 Computing RAOs Tutorial 9 Adding appendages A Appendix A 20mx20m x2m box PatchHull input file B Appendix B PatchHull file format 12 18 24 32 40 45 49 53 54 Introduction The tutorials presented in this document are intended to provide a basic understanding of how to set up compute and simulate various hydrodynamics properties of floating vessels with ShipMo3D ShipMo3D was originally designed for computing wave radiation diffraction and resulting motions of ships but it can also analyse a wide range of floating hull shapes The tutorials are not intended to cover all possible model configurations or capabilities Further information on features and capabilities are de
3. Correction to GM metacentric height m Number of rudders Number of propellers Number of azimuthing propellers Input files for radiation and diffraction and dry panelled hull Radiation and diffraction input file Erua dry panelled hull Ship Radii of Gyration i Roll gyradius m Pitch gyradius m Yaw gyradius m Sea direction 2 of 5ea direction 3 of 5ea direction 4 of 5ea direction 5 of Sea direction 6 of Sea direction 7 of Sea direction amp of 5ea direction 9 of 5ea direction 10 of 13 Sea direction 11 of 13 5ea direction 12 of 13 Sea direction 13 of 13 Computation time 0 s Finished running 5M3D5eakeepRegular3 Figure 38 The BuildShip application s pane highlighting where to specify the RadDif output binary file location the inclusion of the dry panelled hull and the vessel s radii of gyration 3 Defining the retardation function parameters t The build ship application will compute the retardation functions required to perform time domain simulations with radiation effects 41 Tutorial 7 The BuildShip application ShipMo3D Tutorials Under the Terms for evaluation of hull retardation functions section set the time increment to 0 1s the maximum time to 10 0s the encounter frequency increment to 0 2rad s and the maximum encounter frequency of 8 0rad s as shown in Figure 39 including adding a check mark to Use high frequency approximation amp In the Save Run a
4. 0 1 1 0 1 0 1 0 begin hullLine station 0 yOffsets 10 10 54 Appendix B PatchHull file format ShipMo3D Tutorials zOffsets O 2 end hullLine begin hullLine stations 2 2 yOffsets 10 10 zOffsets O 2 hullLine patch end patchHul13 t The station parameter defines at which station the hull line is being define Each hull line point can be defined at a different station by specifying which station each hull line point belongs to using the stations parameter t The station governs the x location of the points and the yOffsets and zOffsets define the y and Z coordinates of the hull line points relative to the baseline t ShipMo3D will fit bi directional b splines through the hull lines to generate a continuous surface c t is recommended that hull lines crossing the calm water line be defined in an order of increasing Z as shown in Figure 48 t The order in which the hull lines and their points are defined is important since they define which side of the surface the surface normal resides on The surface normals should point out The convention for determining a surface patches surface normal direction can be found in figure 49 t Successive hull lines for the port side hull must therefore because defined from the bow to the stern as shown in Figure 50 t For more details on how to create a PatchHull file the reader is referred to the ShipMo3D User Manual 55 Appendix B PatchHull file
5. Max u control segments 40 Max v control segments 40 Nom min length of control segments 0 02 Max degree of u B spline 3 Max degree of v B spline 3 Option for panelling dry hull Panel dry hull Figure 21 Bypassing the patch hull paneling 4 Adjusting the paneling parameters amp Click Save in the Save Run and viewing of Results section amp Click Run in the Save Run and viewing of Results section c After running the PanelHull application 5 greyed out and unclickable plot buttons should now be available for clicking A summary of the results from the application run can be found by clicking View Output Click View Output which will open a new pane titled squareboxPanelHull3 out Scroll down to the section of the results titled PATCH PROPERTIES FOR WET HULL and check the total number of panels used to model the box It should have about 252 panels in total t The PatchHullLine and PatchHullSurface can be visualized by clicking Plot PatchHullLine and Plot PatchHull Surface respectively t he WetPatchHull can be visualized by clicking Plot WetPatchHull The WetPatchHull is the portion of the PatchHull that lies below the calm water line in static equilibrium t Similarly the DryPatchHull can be visualized by clicking Plot DryPatchHull The DryPatchHull is the portion of the PathHull that lies above the calm water line in a static equilibrium Click Plo
6. Qutput Window Figure 8 The vessel global parameters 11 Tutorial 3 Defining hull geometry using hull lines 1 Tutorial overview This tutorial covers e Defining detailed hull geometry using surface patches and hull lines e Defining hull panelling algorithm parameters 2 Patch hull files t ShipMo3D can read detailed hull geometry specified in a patch hull file t The patch hull file is an ASCII text file that defines a set surface patches t A surface patch represents a continuous surface For example an ellipsoid can be modelled using a single patch t Surface discontinuities are handled by using multiple patches For example the hull of a ship may be formed by many patches due to the discontinuities of the top sides and transom of the ship as seen in Figure 9 t ShipMo3D requires geometric information for the port side only It assumes symmetry about the x Z plane and will mirror the geometry to generate the complete hull geometry t Each patch is represented using a series of hull lines t A patch requires at least 2 hull lines t Each hull line requires at lease 1 point 12 Tutorial 3 Defining hull geometry using hull lines ShipMo3D Tutorials Patch 2 Patch 1 Patch 3 Figure 9 Generic vessel patches defined for keel top and transom 3 Creating a patch hull file t Detailed hull geometry will be specified for a simple box hull seen in Figure 10 amp Open the project created i
7. Tutorials amp In the Encounter frequencies for radiation computations rad s section is a table without any rows titled Removed enc freqs rad s Add the frequency entries for 3 2rad s and 4 7rad s as shown in Figure 35 35 Tutorial 6 Computing wave radiation and excitation ShipMo3D Tutorials Box hull analysis Added mass and damping at zero speed 0 20 0 20 Added mass i Damping Added mass ims Damping 0 15 0 15 d 3 a a d di 0 10 0 10 3 E a lt E vU o L3 zi z A i 0 05 0 05 0 00 0 00 o 2 6 8 10 10 Encounter frequency o rad s Encounter frequency o rad s 10 4 Added mass iw Damping Added mass we Damping 8 3 lt e 3 di 3 p 2 3 E aq p 4 3 E 2 g 1 I 1 EN 2 s s N I M I N I gt 4 0 ese ew ew 0 4 TO A ma ee ep A o 2 6 8 10 0 2 4 6 8 10 Encounter frequency w rad s Encounter frequency o rad s 0 20 Added mass i Damping Added mass Damping 3 0 15 3 d t E 3 i a 22 0 10 S D 4 3 E d 9 d s IN 1 0 05 s N s 4 o 4 T UR ma uum emm um mi o sg A 0 00 0 2 4 6 8 10 10 Encounter frequency w rad s Encounter frequency co rad s 6000 10000 5000 8000 6 4000 5 S E 5 6000 E S 3000 amp m 3 5 2 4 4000 amp ml 2000 2000 1000 o 0 o 2 6 8 10 o 2 5 6 8 10 Encounter frequency w rad s Encounter frequency
8. Viewing of Results tiii Console Output Window Input file C ShipMo3D Tutorials simpleVessel simpleVesselBui ldShip3 inp Output file C ShipMo3D Tutorials simpleVessel simpleVessel Bui ldShip3 out Input file opened Reading input file C ShipMo3D Tutorials simpleVessel simpleVesselBui ldShip3 inp Computation time Os I i Running SM3DBuildShip3 Finished running SM3DBuildShip3 Figure 13 The PanelHull s panelling parameters e Save the project e Click Run in the Save Run and viewing of Results section of PanelHull c After running the PanelHull application check the summary of results by clicking View Output which will open a new pane titled simpleVesselPanelHull3 out OQ Scroll down to the section of the results titled PATCH PROPERTIES FOR WET HULL and check the total number of panels used to model the hull It should have about 556 panels in total This is a coarse mesh and more refined hydrodynamic effects will be obtained with more panels t The patch hull lines and surfaces can be visualized by clicking Plot PatchHullLine and Plot PatchHullSurface respectively cS Plot WetPatchHull illustrates the portion of the hull that lies below the water line in static equilibrium 16 Tutorial 3 Defining hull geometry using hull lines ShipMo3D Tutorials t Similarly Plot DryPatchHull illustrates the portion of the hull that lies above the water lin
9. a selection box over the whole object and click the Mesh from surface poly surface x The Polygon Mesh Detailed Options menu will pop up Q Set meshing properties as shown in Figure 19 20 Tutorial 4 Defining hull geometry with an existing mesh ShipMo3D Tutorials La Polygon Mesh Deta Figure 19 Polygon Meshing Options t Now that the surfaces are meshed they are no longer needed Delete the remaining surfaces by selecting them individually ts All that remains is the mesh to be exported to an obj file Figure 20 Surfaces to be deleted Q Select all of the mesh and go to File Export Selected amp Call the mesh squarebox obj and leave the OBJ Export Options as default 21 Tutorial 4 Defining hull geometry with an existing mesh ShipMo3D Tutorials 3 Importing a custom mesh into ShipMo3D amp Start a ShipMo3D project as done previously and create a new PanelHull amp Call the Project squarebox Instead of specifying a patch hull input file select the Import panel hull from OBJ and bypass panelling box O Browse to the location of squarebox obj for the OBJ input file OBJ file import panelHull bypass patchHull panelling W Import panel hull from OBJ and bypass panelling OBJ input file not selected Browse Patch hull input file name and patch fit parameters Full run including panelling of hull Patch hull input file not selected Browse
10. any other parameters in the Project pane Tutorial 1 Creating a new ShipMo3D project ShipMo3D Tutorials f sampleProject ShipMo3D 3 3 Version 3 3 release 12 December 2013 File Edit Application Run Output Plot Help Project ShipMo3D Project Project directory CAShipMa3D Tutorials sample project Project name samplePraject Default filename prefix sampleProject Default label My first sample ShipMo3D project Ship Dimensions and Loading Condition E Read only Ship length m Station of aft perpendicular Water density kg m3 Piet nf lee alien at eee ee feel le ae fe iir Console Output Window Figure 1 ShipMo3D project parameters 3 ShipMo3D s application based work flow t ShipMo3D uses a collection of separate applications to perform tasks such as generating a vessel hull mesh specifying hull appendages and computing wave radiation and diffraction effects t Each application has a specific task and generates data for use in the project by other applications t As applications are added to a project they are opened in a new pane t Usually only a few applications are required for each project though this depends on the specific analysis objectives t A list of all applications can be seen under the Application menu as seen in Figure 3 t The role of several commonly used applications is listed in Table 1 Tutorial 1 Creating a new ShipMo3D project ShipMo3D Tutorials sam
11. are overly skewed polygon sizes are not uniform the mesh contains a combination of large and small polygons The mesh resolution is too coarse The mesh is not a closed surface or it has interpenetrating polygons Figure 24 is poor as it includes polygons with high aspect ratio and a very coarse mesh Tutorial 5 Fixing a poorly conditioned mesh ShipMo3D Tutorials Figure 24 The poorly conditioned mesh imported in Rhino3D A polygon with high aspect ratio is highlighted 4 Reconstituting a new continuous geometric model t n order to produce a new well conditioned mesh of the geometry new geometry is reconstituted using continuous surfaces Enable object snap Osnap Mid snap and point snap as shown in Figure 25 End Near Point Mid Cen Int Pep Tan Quad Knot T Project N STrack Disable CPlane x14 00 y 12 00 z 0 00 0 00 a Default Snap Ortho Planar Osnap Record History Figure 25 The Osnap Mid and Point snap buttons This box has 6 sides each side will be modelled using a continuous surface Because of the simplicity of the geometry a surface will be constructed using two single segment polylines Osnap allows the mouse cursor to snap onto geometrical features The Point object snap setting allows the cursor to snap to mesh vertices points Select the Surface from 3 or 4 corner points tool Oo A ARR The Surface from 3 or 4 corner points tool is highlighted in Figure
12. azimuthing propellers Application Data Files PanelHull RadDif PanelSloshTank RadSloshTank BuildShip BuildSeaway FreeMo SeakeepRegular SeakeepRandom SeakeepSeaway SeakeepSeawayFromRaos TimeSeriesFromRaos lt not selected not selected znot selected not selected not selected not selected not selected EE lt not selected not selected znot selected not selected Exclude Exclude Exclude Exclude Exclude Exclude Exclude Exclude Exclude Exclude Exclude Exclude Figure 3 List of application data in the project Delete Delete Delete Delete Delete Delete Delete Delete Delete Delete Delete Delete Tutorial 2 Fundamental vessel parameters 1 Tutorial overview This tutorial covers e Creating a simple vessel for analysis e Fundamental and global vessel parameters e Defining basic model dimensions e Defining static loading conditions 2 Defining global vessel parameters r A simple vessel consisting of a square box seen in Figure 4 is used for this project amp Open ShipMo3D and create a new project Q Specify a project name and directory location in the ShipMo3D Project section d 2m pm K sta Figure 4 Vessel hull dimensions 3 Hull stations t The vessel hull general dimensions and loading conditions are referenced by several applications and are set in the Proje
13. exporting it to an obj file t ShipMo3D does not recognize mesh vertices in the negative portion of each axis so when creating the mesh keep all vertices in the positive X y and Z axes t The baseline is at z O t The aft most vertices should be located at or near x 0 Select Box Corner to Corner Height on the left side tool bar 18 Tutorial 4 Defining hull geometry with an existing mesh ShipMo3D Tutorials Figure 15 Box Corner to Corner Height button Place the first corner on the origin in the Top view window Place the second corner 20m along the x axis and 10m along the y axis O n one of the other views that shows the z axis extend the box 2m in the positive z direction Figure 16 20x10x2m Rhino3D surface t n order to control the meshing process the single box surface must be exploded into separate surfaces Q Select the box and click the Explode button 19 Tutorial 4 Defining hull geometry with an existing mesh ShipMo3D Tutorials Figure 17 Explode button do HOV GP SSID OU amp e bh amp o00 S amp ED Ge JJ OuS SEL S Sa o hh t Since ShipMo3D mirrors the panels supplied to it the surface on the inside of the hull is not needed Q Select the surface that is aligned with the x axis and delete it by pressing the Delete button on the keyboard Figure 18 Inside surface Select all the surfaces by dragging
14. for Box Side Patch dry Making panels for Box Top Patch dry Making panels for back patch dry Making panels for front patch dry Computation time 3 5 Finished running 5M3DPanelHull3 Figure 33 The RadDif application s pane highlighting the radiation computation s encounter frequency range amp In the Save Run and Viewing of Results section click Save and then click Run amp After ShipMo3D is done processing the radiation computations click Plot RadCo r A new pane should have opened titled Plot RadCo with non dimensional added mass and damping plotted against oscillation frequency The plot should resemble the one shown in figure 34 c There are a few irregular frequencies in the data An irregular frequency is a frequency band where the system is poorly conditioned for resolving the potential flow solution Poor conditioning leads to inaccuracies in the potential flow solution and generally produces discontinuities in the added mass and damping plots at those frequencies Poor condition numbers can be seen at frequencies around 3 2rad s and 4 7rad s in the longitudinal and lateral condition number plots These correspond to discontinuities in the surge sway roll and pitch added mass plots t To produce well conditioned added mass and damping plots these irregular frequencies can be removed from the computations 34 Tutorial 6 Computing wave radiation and excitation ShipMo3D
15. mesh Repeat these steps for the remaining 5 surfaces using the same meshing settings t When completed the mesh and continuous surfaces should both remain as shown in Figure 31 Figure 31 The newly meshed continuous surfaces showing a well conditioned mesh 6 Exporting the mesh geometry to OBJ file The Rhino scene now contains the 6 continuous surfaces and the 6 meshes The newly created meshes are now well conditioned for computation purposes The mesh is ready to be processed for importation in ShipMo3D a A A R To prepare the mesh for import into ShipMo3D the reader is referred to Tutorial 31 1 Tutorial 6 Computing wave radiation and excita tion Tutorial overview This tutorial will guide the reader through the effects of wave radiation and determining the wave excitation loads on the body using 3D potential flow panel method The wave excitation loads include the computation of both incident wave loads as well as wave diffraction loads In order to compute the hydrodynamic forces acting on the body the hull geometry must be panelled as described in Tutorial That is it s surface must be discretized into small panels which creates a computational mesh The panels are used to compute the potential flow solution as well as to integrate hydrodynamic pressures over the surface of the hull This tutorial covers e Computing radiation effects database Understanding how frequency of oscillation affects add
16. o rad s Figure 34 A plot of non dimensional added mass and damping plotted against oscillation frequency for the 20m x20mx2m box case 36 Tutorial 6 Computing wave radiation and excitation ShipMo3D Tutorials 3 release 12 December 2013 eos m Sm l File Edit Application Run Output Plot Help Ship Radii of Gyration for Non dimensional Hydrodynamic Coefficients Use default values Roll gyradius m 5 8 Pitch gyradius m 5 8 YawGyradius gyradius m 82 Options for Computing Hydrodynamic Coefficients Use default values Encounter frequencies for radiation computations rad s Enc freq rad s Range or array Min Removed enc fregs rad s Longitudinal mode condition limits Enc freq rad s Condition limit 0 0 100000 0 14 0 100000 0 Add row Delete row Lateral mode condition limits Enc freq rad s Condition limit 0 0 100000 0 14 0 100000 0 Add row Delete row Making panels for Box Side Patch wet Making panels for back patch wet Making panels for front patch wet Panelling dry hull Making panels for Box Side Patch dry Making panels for Box Top Patch dry Making panels for back patch dry Making panels for front patch dry Computation time 3 s Finished running 5M3DPanelHull3 Figure 35 The RadDif application s pane highlighting how to removing irregular frequencies amp In the Save Run and Viewing of Results section click Save and then cli
17. 26 26 Tutorial 5 Fixing a poorly conditioned mesh ShipMo3D Tutorials to VQ oh amp SSIOGU r me a Y m b S os Figure 26 The Surface from 3 or 4 corner points tool s button t Each side of the box will be recreated as a continuous surface using the Surface from 3 or 4 corner points by letting the cursor snap to the 4 corners that define each sides and click them amp With the Surface from 3 or 4 corner points selected snap to and click the 4 corners of the top side of the box t This will create a surface representation of the top side of the box as shown in Figure 27 27 Tutorial 5 Fixing a poorly conditioned mesh ShipMo3D Tutorials Figure 27 The creation of a continuous surface patch highlighted yellow created by snapping to 4 corners red x of the mesh po Repeat the process of creating continuing surfaces for the remaining 5 sides The results will look like that shown in Figure 28 Now that the geometry is perfectly represented using continuous surfaces the poorly discretised mesh can be deleted from the Rhino scene Select the original mesh geometry so that it s highlighted yellow and delete it by pressing the Delete or Del key on the keyboard After deleted the original mesh only the continuous surface representation of the box will remain as shown in Figure 29 28 Tutorial 5 Fixing a poorly conditioned mesh ShipMo3D Tutorials Figure 28 T
18. cifying a patch file and fit parameters t The patch hull file specified has 5 surface patches the bottom top side front and back patches t PanelHull only uses the half of the hull geometry in the positive y axis side of the x Z plane The geometry is assumed symmetric and is mirrored about the x Z plane to produce the complete hull r A graphic representation of the mirrored hulls lines used to define the surface patches and the surface patches themselves are presented in Figures 11 and 12 respectively amp leave the remaining parameters in section Patch hull input file name and patch fit parameters at default values as indicated in Figure 13 Figure 11 The hull lines used to define the 5 patches The lines of each patch are different colours The plane Figure 12 The 5 surface patches that define the vessel about which the patches are mirrored is also indicated hull 14 Tutorial 3 Defining hull geometry using hull lines ShipMo3D Tutorials 6 Adjusting the panelling parameters Check the Panel dry hull checkbox in the Option for panelling dry hull section t Panelling the dry hull allows for complete visualisation of the hull as well as for the use of nonlinear buoyancy and Froude Krylov in FreeMo simulations O Uncheck the Compute draft and trim based on input displacement and LCG from the Option for Computing Draft and Trim from Displacement and LCG section t f the displacem
19. cing RAOs The manoeuvring models that can be defined and added to a vessel in the BuildShip application will affect RAO predictions For this square box application the most signification impact to RAO will be in the yaw degree of freedom In the Save Run and Viewing of Results section of the SeakeepRegular pane click Run In the Save Run and Viewing of Results section of the SeakeepRegular pane click Plot MotionRAO The plotted RAO results in the newly opened Plot Motion RAOs pane should now resemble those shown in Figure 4T The sway roll and yaw DOFs were all affected The yaw DOF was most significantly affected as can be seen by comparing Figure 44 against Figure 47 51 Tutorial 9 Adding appendages ShipMo3D Tutorials simpleVessel Box hull analysis Motion RAOs speed 0 m s sea direction 45 deg Line 1 Box hull analysis 0 8 Title Line 2 Motion RAOs speed 0 m s sea dii e o o e Ship speed m s Sea dir deg Graph columns Surge RAO n l a ae A Sway RAO n a o e N o iy Surge Heave 0 5 1 0 1 5 x 0 5 1 0 5 Pitch Wave frequency w rad s Wave frequency w rad s pa N Sway pa o Roll eo to o o Yaw 9 n Plot size parameters Heave RAO n a m o o Roll RAO nal k a e iu Width mm 150 o N Height mm e o Image format e 0 5 1 0 1 5 A 0 5 1 0 1 5 Wave frequency w rad s Wave
20. ck Run amp After ShipMo3D is done processing the radiation computations click Plot RadCo t The added mass and damping plots will resemble those shown in Figure 36 t Note how the added mass and damping plot are no longer exhibit sharp discontinuities 37 Tutorial 6 Computing wave radiation and excitation ShipMo3D Tutorials 0 20 Box hull analysis Added mass and damping at zero speed Added mass i Damping o my uw Surge Au M Bu M o eo m e 0 05 Encounter frequency o rad s 10 10 Added mass we Damping Heave A M Bs M o Encounter frequency o rad s Added mass irr UJ Pitch Ass Iss Bss Iss c0 N Encounter frequency w rad s 2500 2000 1500 1000 Longitudinal condition 500 0 2 6 8 Encounter frequency w rad s Figure 36 A plot of non dimensional added mass and damping plotted against oscillation frequency for the 20m x 20mx2m box case Irregular frequencies have been removed 10 Damping 10 10 0 20 Added mass ms Damping e m Uu 0 10 Sway A22 M B22 M c 0 05 10 Encounter frequency o rad s Added mass we Damping Ww Roll Asa Iss Bas Ls c0 N Encounter frequency w rad s 0 20 Added mass Damping 0 15 Yaw Ass Ise Bes Iee c0 o H o 0 05 10 Encounter frequency w rad s 1000 800 600 Lateral condition 400 200 0 2 x 6 8 10 Encount
21. ct pane in the Ship Dimensions and Loading Condition section Tutorial 2 Fundamental vessel parameters ShipMo3D Tutorials Set Ship length to 20m t The ship length corresponds to the ShipMo3D frame X direction t Hull geometry is defined relative to the baseline and a number of equidistant stations that span from the bow to the aft of the vessel as shown in Figure 5 t The bow of the vessel is always station 0 and the user specifies the station number at the aft of the ship Q Set Station of aft perpendicular to 2 c With this setting and hull length specified station 1 is 10m and station 2 is 20m from the bow respectively Station 2 Station 1 Station O Stern P nm Z 0 Baseline 20m Figure 5 The length of the vessel the baseline relative to the hull geometry and the location of each station specified 4 Fundamental static loading parameters t Detailed hull geometry is defined in the PanelHull application t Before detailed hull geometry is defined several fundamental vessel parameters must be set t These fundamental parameters include static loading values which along with the detailed hull geometry are used to automatically compute the displacement and longitudinal center of gravity CG of the vessel t The static loading parameters that define the equilibrium state as indicated in Figure 6 are water density draft of the baseline at midship draftBIMid trim of the baselin
22. e by stern trimBlStern KG height of the CG above baseline correction to GM metacentric height Midship Figure 6 The static equilibrium state of a generic vessel Tutorial 2 Fundamental vessel parameters ShipMo3D Tutorials 5 Setting specific static loading parameters The specific static loading parameters for the simple vessel must be set Set Draft of baseline at midships to 1 0 Set KG height of CG above baseline m to 1 0 o 0 6 4 Leave all other parameters at their default values Figure 7 The vessel static condition 6 Setting the number of rudders and propellers Set Number of rudders to 0 Set Number of propellers to 0 The list of parameters should appear as in Figure 8 o 5 ooo Save the project 10 Tutorial 2 Fundamental vessel parameters ShipMo3D Tutorials Run Output Plot Help Project PanelHull ShipMo3D Project Project directory CAShipMo3D Tutorials simpleVessel Project name simpleVessel Default filename prefix simpleVessel Default label Box hull analysis Ship Dimensions and Loading Condition Read only Ship length m Station of aft perpendicular Water density kg m3 Draft of baseline at midships m Trim of baseline by stern m KG height of CG above baseline m Correction to GM metacentric height m Number of rudders Number of propellers Number of azimuthing propellers Console
23. e in static equilibrium Click Plot PanelHull in the Save Run and Viewing of Results section This should open up a new pane titled Plot PanelHull In the Shading and meshing section of this new pane add a check mark to the Show panel outlines checkbox This will show the outlines or edges of each panel This provides a graphic representation of the resolution of the mesh t fthe mesh is not corrupted does not have any significant holes anomalies or inconsistencies the panelling process is completed t The mesh on different faces or patches does not need to align t he produced mesh should resemble the one found in Figure 14 Figure 14 The panelled hull of the vessel 17 Tutorial 4 Defining hull geometry with an existing mesh 1 Tutorial overview This tutorial covers e Defining simple hull geometry using Rhino3D e Importing a custom mesh 2 Generating a mesh in Rhino3D t A custom mesh can be used to represent the panels on a hull t This can be done using the 3D modeling software Rhino3D Create a new object in Rhino3D using the Large Objects Meters 3dm template Save the object as squarebox 3dm t Since ShipMo3D only requires half of a hull split longitudinally creating a 20x20x2m block in ShipMo3D requires a 20x10x2m hull mesh created in Rhino3D t t is good practice to model the hull split down the x axis in Rhino3D so no frame rotations are necessary when
24. ed mass and damping Computing wave excitation loads Pre processing wave radiation effects In order to compute wave radiation effects and wave excitation loads the RadDif application requires the wetPanelHull data that was produced by the PanelHull application Click File Add New Data RadDif A new pane has opened with a tab titled RadDif In Tutorial when the Run button was pressed a binary Wet Panel Hull file was produced as output called squareBoxWetPanelHull bin and stored in the project directory In the Wet Panel Hull File section of the RadDif pane select the Wet panel hull input file Under the Ship Radii of Gyration of Non dimensional Hydrodynamic Coefficients section uncheck the Use default values checkbox and enter the roll pitch and yaw radii of gyration properties of 5 8m 5 8m and 8 2m respectively as shown in Figure 32 32 Tutorial 6 Computing wave radiation and excitation ShipMo3D Tutorials simpleVessel ShipMc sion 3 3 release 12 December 2013 Sce File Edit Application Run Output Plot Help PanelHull Ship Dimensions and Loading Condition Read only Ship length m Station af aft perpendicular Water density kg m3 Draft of baseline at midships m Trim of baseline by stern m KG height of CG above baseline m Correction to GM metacentric height m Number of rudders Number of propellers Number of azimuthing propellers Wet Panel Hul
25. ent and LCG longitudinal cg location are provided ShipMo3D will use an iterative procedure to determine the static equilibrium state and determine the ship s draft and trim In the Panelling parameters section set Limit on area for panels to 1 0 and the Limit on aspect ratio for panels to 2 0 O Leave remaining parameters in Panelling parameters at default values t Parameters should be set as indicated in Figure 13 15 Tutorial 3 Defining hull geometry using hull lines ShipMo3D Tutorials sin p ue V Wes File Edit Application Run Output Plot Help PanelHull l OBJ file import panelHull bypass patchHull panelling E Import panel hull from OBJ and bypass panelling OBJ input file not selected Patch hull input file name and patch fit parameters Full run including panelling of hull Patch hull input file CAShipMo3D Tutorials simpleVessel Big_box inp Max u control segments 40 Max v control segments 40 Nom min length of control segments 9 1 Max degree of u B spline 3 Max degree of v B spline 3 Option for panelling dry hull V Panel dry hull Option for Computing Draft and Trim from Displacement and LCG E Compute draft and trim based on input displacment and LCG i i Panelling parameters i Limit on area for panels m2 1 0 Limit on aspect ratio for panels 2 0 Limit on normal angle between adjacent panels deg 15 0 Save Run and
26. er frequency w rad s 38 Tutorial 6 Computing wave radiation and excitation ShipMo3D Tutorials t Now that the radiation effects solution is acceptable the wave excitation loads can be included in the computations amp In the Diffraction Computation Parameters section set the speed units to m s the ship speeds minimum and maximum to 0 0m s the relative sea directions to span between 0 0degrees and 180degrees at 15degree increments and the wave frequencies to range between 0 2rad s to 2 0rad s at 0 2rad s increments as shown in Figure 37 Enable the wave excitation computations by adding a check to Include diffraction computations ts This option will compute the 6 DOF wave excitation force amplitudes and phase relative to the wave s phase both incident wave forces and diffracted wave forces for a set of ship speed relative sea direction and wave frequency combinations OQ In the Save Run and Viewing of Results section click Save and then click Run File Edit Application Run Output Plot Help Resi Diffraction Computation Parameters Speed units Ship speeds m s Range or array Min Max Increment Relative sea directions deg Range or array Min Max Increment Wave frequencies rad s Range or array Min Max Increment Include diffraction computations Speed for Output Forward Speed Radiation Coefficients Units Froude number Speed 0 2 TELE bie bo wer Lae Loe A E
27. fDB bin Include dry panelled hull Ship Radii of Gyration Roll gyradius m 5 8 Pitch gyradius m 5 8 Yaw gyradius m 8 amp 2 Terms for evaluation of hull retardation functions Time increment s Maximum time s Encounter frequency increment rad s Maximum encounter frequency rad s se high frequency approximation Evaluating Green functions Encounter frequency 6 7 rad s Evaluating Green functions Encounter frequency 7 2 rad s Evaluating Green functions Encounter frequency 7 7 rad s Evaluating Green functions Encounter frequency 8 2 rad s Evaluating Green functions Time for computing coefficients 12 s Finished runnina SM3DRadDif3 Figure 39 The BuildShip application s pane highlighting the parameters required to compute the retardation functions 42 Tutorial 7 The BuildShip application ShipMo3D Tutorials 4 5 amp O Box hull analysis Retardation functions at zero speed 1 5 1 5 Surge K n M g L Sway K z M g L Delay time r s Delay time r s ve K M g L N Roll K s4 Ise g L Hea o n c m o N o n c m o 2 4 Delay time T s Delay time r s Pitch K ss Iss g L Yaw K ss Iss g L 6 8 10 0 2 4 6 8 10 N o Delay time T s Delay time T s Figure 40 A plot of the square box s retardation functions Defining manoeuvring model parameters For this tutorial manoeuvring models are ignore The complete BuildShip model will not
28. format ShipMo3D Tutorials Design waterline Figure 48 A example hull line t direction of successive points on a hull line s direction of successive hull lines n normal pointing outward from hull Figure 49 Convention for evaluating surface patch s surface normal Hull line 0 Hull line 1 Hull line 2 Hull line n 1 e Bow Stern Baseline Figure 50 The profile of a hull s port side surface patch s hull lines 56
29. frequency w rad s Pitch RAO ns k a a o o Yaw RAO n k a o o m H e ul o N e o Ul 0 5 1 0 1 5 a x 0 5 1 0 1 5 Wave frequency o rad s Wave frequency o rad s Sea direction Sea direction Sea direction Sea direction Sea direction Sea direction Sea direction Sea direction Sea direction Sea direction Sea direction 12 Sea direction 13 Computation time Seeenauswn Finished running SM3DSeakeepRegular3 Figure 47 The square box RAOs with the skeg 52 Appendix A file begin patchHull3 label box lengthData 20 2 begin patch label Box Bottom Patch normalRanges 1 0 1 0 1 1 0 1 0 1 0 begin hullLine station 0 yOffsets 0 10 zOffsets 0 0 end hullLine begin hullLine station 2 yOffsets 0 10 zOffsets 0 0 end hullLine end patch begin patch label Box Side Patch normalRanges 1 0 1 0 1 1 0 1 0 1 0 begin hullLine station 0 yOffsets 10 10 zOffsets 0 2 end hullLine begin hullLine station 2 yOffsets 10 10 zOffsets 0 2 end hullLine end patch begin patch label Box Top Patch normalRanges 1 0 1 0 1 1 0 1 0 1 0 begin hullLine station 0 yOffsets 10 0 zOffsets 2 2 end hullLine begin hullLine station 2 yOffsets 10 0 zOffsets 2 2 end hullLine end patch begin patch label back patch normalRanges 1 0 1 0 1 1 0 1 0 1 0 begin hullLine station 2 yOffsets 10 10 zOffsets 0 2 end hullLine begin hullLine station 2 yOffsets 0 0 zOffsets 0 2 end h
30. he poorly conditioned mesh with the 6 continuous surfaces created to replace it The continuous surfaces are highlighted in yellow Figure 29 The 6 continuous surfaces only with the poorly conditioned mesh removed 29 Tutorial 5 Fixing a poorly conditioned mesh ShipMo3D Tutorials 5 Producing a new mesh from the continuous surfaces t The continuous surfaces can be discretised and meshed as finely or coarsely as desired and the quality of the mesh can be controlled c t is recommended that each surface is meshed individually This provides individual control over the mesh for each surface Select one of the surfaces o Q Select the Mesh from Surface tool c A new dialogue titled Polygon Mesh Detailed Options will appear t The Mesh from Surface tool is highlighted in Figure 30 J e qo GuUOe sx gt FF K amp lQ 2 D 9 m b oq 5 os Figure 30 The Mesh from Surface tool s button Q Set Density to 1 0 amp Set Maximum angle to 90 amp Set Maximum aspect ratio to 2 0 Set Minimum edge length to 0 0 no minimum Set Maximum edge length to 0 5 Set Maximum distance edge to surface to 0 0 no maximum Set Minimum initial grid quads to 0 0 no minimum 30 Tutorial 5 Fixing a poorly conditioned mesh ShipMo3D Tutorials amp Click Preview to see what the produced mesh will look like amp If the mesh looks like it will be acceptable click OK to accept the
31. include any viscous loading terms Under the Ship Resistance section set all parameters as shown in Figure 41 Under the Hull Roll Eddy and Lateral Drag Coefficients section set all coefficients to 0 0 as shown in Figure 41 The Maneuvering Coefficients and Ship Appendages section parameters can be left default In the Save Run and Viewing of Results section click Save and then click Run This produced a serialized binary containing the complete ship model parameters 43 Tutorial 7 The BuildShip application ShipMo3D Tutorials a simpleVessel ShipMo3D 3 3 Version 3 3 release 12 December 201 File Edit Application Run Output Plot Help Project PanelHull RadDif BuildShip Ship Resistance Speed units ms X Resistance option InputResist Resistance coefficients R 0 5 rho A U 2 Speed Resist Co 0 0001 0 0 1 0 0 0 Add row Delete row Hull Roll Eddy and Lateral Drag Coefficients Lateral drag normally set to 0 already included in maneuvering Roll eddy drag 0 0 Lateral drag 0 0 Maneuvering Coefficients Source of hull dimensions Load condition data w Maneuvering coefficient method Inoue X E Adjust Inoue coefficients Ship Appendages Bilge keels Lg Foils Ld Skegs Evaluating Green functions Encounter frequency 6 7 rad s Evaluating Green functions Encounter frequency 7 2 rad s Evaluating Green funct
32. ions Encounter frequency 7 7 rad s Evaluating Green functions Encounter frequency 8 2 rad s Evaluating Green functions Time for computing coefficients 12 s Finished runnina SM3DRadDif3 Figure 41 The BuildShip application s pane highlighting how to disable the ship s resistance and lateral drag models 5 Exporting a hydrodynamics database for use in ProteusDS t ShipMo3D can export a database to handle the modelling of radiation and wave excitation loading t ShipMo3D will also export the ship resistance model and the lateral drag model For this tutorial these were disabled by zeroing their coefficients t The database is exported in a ProteusDS compatible format in the form of an ASCII text file amp In the Save Run and Viewing of Results section click ProteusDS Export O Choose an appropriate file name like squareBoxSM3D ini and save it at some file path where it can later be retrieved 44 Tutorial 8 Computing RAOs 1 Tutorial overview This tutorial will guide the reader through the computation of response amplitude operators RAOs This step requires the reader to have completed Tutorial and have a BuildShip output binary database file ready for use This tutorial covers e Computing RAOs e Exporting RAOs for use in ProteusDS 2 Producing RAOs amp Click File Add New Data SeakeepRegular ts A new pane should have opened with a tab titled SeakeepRegular t n Tutorial when the R
33. l File Wet panel hull input file CAShipMo3D Tutorials simpleVessel simpleVesselWetPanelHull bin Browse Ship Radii of Gyration for Non dimensional Hydrodynamic Coefficients Use default values Roll gyradius m Pitch gyradius m YawGyradius qyradius m Making panels tor back patch wet Making panels for front patch wet Panelling dry hull Making panels for Box Side Patch dry Making panels for Box Top Patch dry Making panels for back patch dry Making panels for front patch dry Computation time 3 5 Finished running 5M3DPanelHull3 Figure 32 The RadDif application s pane highlighting the roll pitch and yaw radii of gyration um AX a c E t he Options for Computing Hydrodynamic Coefficients can be left default Under the Encounter frequencies for radiation computations rad s section of the RadDif pane set the Min Max and increment Encounter frequencies as 0 2rad s 8 2rad s and 0 5rad s fill out the parameters as shown in Figure 33 r he encounter frequency includes the effect a ship s mean forward speed has on the perceived frequency of the waves relative to the moving ship If the ship is moving against the waves the encounter frequency will be higher than the wave s frequency If the ship is moving with the waves the encounter frequency will be lower than the wave s frequency O Under the Diffraction Computation Parameters uncheck
34. le location Under the Ship speeds headings and wave frequencies section of the SeakeepRegular pane enter the ship speed range using units of m s and supplying a minimum and maximum of 0 0m s Also set the relative sea direction range as between 0 0degrees to 180degrees with 15degree increments and the wave frequency range as between 0 2rad s to 2 0rad s with 0 05rad s increments as shown in Figure 43 x This instructs ShipMo3D to compute RAOs for every combination of these discrete ship speeds sea direction and wave frequencies amp In the Save Run and Viewing of Results section click Save and then click Run 46 Tutorial 8 Computing RAOs ShipMo3D Tutorials File Edit Application Run Output Ship speeds headings and wave frequencies Speed units Ship speeds m s Range or array Min Max Increment Relative sea directions deg Range or array Min 0 0 Max 180 0 Increment 15 0 Wave amplitude option Constant steepness Wave frequencies rad s Range or array Min Max Increment Wave steepness H wavelength Console Output Window Running 5M3DBuildSh1p3 Input file C ShipMo3D Tutorials simpleVessel simpleVesselBui ldShip3 inp Output file C ShipMo3D Tutorials simpleVessel simpleVesselBuildSh1ip3 out Input file opened Reading input file C yShipMo3D TutorialssimpleVesselsimpleVesselBuildShip3 1np Computation time Os Finished running 5M3DBuildSh1p3
35. m y Making panels for Box Side Patch wet Making panels for back patch wet Making panels for front patch wet Panelling dry hull Making panels for Box Side Patch dry Making panels for Box Top Patch dry Making panels for back patch dry Making panels for front patch dry Computation time 3 5 Finished running 5M3DPanelHul13 Figure 37 The RadDif application s pane highlighting the vessel s speed relative sea directions and wave frequencies to use to compute the wave excitation load database 39 1 Tutorial 7 The BuildShip application Tutorial overview This tutorial will guide the reader through the creation of the ship model This step generally includes defining manoeuvring models and appendages such as rudders and propellers This simple square box example will not include any appendages or manoeuvring models These will be created in a future tutorial This tutorial covers Evaluating the retardation functions for radiation effect modelling Quick overview of building a complete ship model for time domain or frequency domain analysis Exporting a radiation and diffraction database for use in ProteusDS Including radiation diffraction database and defining radii of gyration Click File Add New Data BuildShip A new pane should have opened with a tab titled BuildShip In Tutorial when the Run button was pressed a binary file was produced as output called squareBoxRad DifDB bin and stored i
36. n Tutorial t The box has 6 continuous surface patches to define each sides E 2m pm 20m M Figure 10 Vessel hull dimensions Q Create a new empty ASCII text file in any text editor program and save it as box inp in the ShipMo3D project folder Copy the contents of the patch hull file in Appendix A into the new text file and save it t A detailed explanation of the format and contents of the patch hull file to be used is listed in Appendix B 13 Tutorial 3 Defining hull geometry using hull lines ShipMo3D Tutorials 4 The PanelHull application t The PanelHull application provides a detailed and discretised hull form for the project c PanelHull will create the discrete hull automatically from hull lines or by importing an existing mesh amp Click File 5 Add New Data PanelHull t n the new PanelHull pane are sections titled PanelHull and Ship Dimensions and Loading Condition which are copied from the Project pane Leave Ship Dimension and Loading Condition parameters as read only Leave the Import panel hull from OBJ and bypass panelling unchecked in the OBJ file import panelHull bypass patchHull panelling section Under the Patch hull input file name and patch fit parameters section ensure Full run including panelling of hull is checked Under Patch hull input file browse to the project folder location and select Box inp 5 Spe
37. n the project directory This file includes added mass and damping properties as a function of frequency as well as wave excitation loads amongst other things In the Input files for radiation and diffraction and dry panelled hull section of the BuildShip pane select the squareBoxRadDifDB bin input file as shown in Figure 38 The include dry panelled hull checkbox can be left unchecked Under the Ship Radii of Gyration of Non dimensional Hydrodynamic Coefficients section uncheck the Use default values checkbox and enter the roll pitch and yaw radii of gyration of 5 8m 5 8m and 8 2m respectively for the vessel as shown in Figure 38 The radii of gyration defined in the RadDif application were only used to non dimensionalise the added mass and damping plots The radii of gyration defined here will be used to compute the physical 6 DOF inertia matrix for the body 40 Tutorial 7 The BuildShip application ShipMo3D Tutorials simpleVessel ShipMo3D 3 3 Version 3 3 release 12 December 20 Se File Edit Application Run Output Plot Help BuildShip Data directory CAShipMo3D Tutorials simpleVessel Filename prefix simpleVessel Input label Box hull analysis Input note Ship Dimensions and Loading Condition Read only Ship length m Station of aft perpendicular Water density kg m3 Draft of baseline at midships m Trim of baseline by stern m KG height of CG above baseline m
38. nd Viewing of Results section click Save and then click Run Click the newly available Plot Retard button c A new pane titled Plot Retard should have appeared showing the Kernel functions plotted against delay time elapsed time It should resemble the plots shown in Figure 40 t A sign that the retardation function are numerically well conditioned is that their oscillations decay to zero with time c The maximum time of the retardation functions should be chosen to be large enough to capture their decay to near Zero t The time increment controls the time discretisation of the retardation functions t he computation of the retardation function is completed by performing a frequency integral of added mass or damping The encounter frequency increment controls the that integration s step size The maximum encounter frequency controls the bound of the frequency integral m simpleVessel ShipMo3D 3 3 Version 3 3 release 12 December 201 File Edit Application Run Output Plot Help Project PanelHull RadDif BuildShip Trim of baseline by stern m 0 0 KG height of CG above baseline m 1 0 Correction to GM metacentric height m 0 0 Number of rudders 0 Number of propellers 0 Number of azimuthing propellers 0 Input files for radiation and diffraction and dry panelled hull Radiation and diffraction input file CAShipMo3D Tutorials simpleVessel simpleVesselRadDi
39. pleProject Shi Mo3D 3 3 Version 3 3 release 12 December 2013 P J P File Edit Application Run Output Plot Help utorials sample project t ShipMo3D project Ship length Station of a Water density kg m3 Ment mE bee alien mh a de ne feel dkk Console Output Window Figure 2 Available applications Application Description PanelHull Creates the vessel geometry and computational panel mesh RadDif Computes a database of wave radiation and excitation effects BuildShip Defines additional manoeuvring models such as any appendages like rudders propellers skegs and keels BuildSeaway Defines parameters for the sea state conditions SeakeepRegular Computes frequency domain vessel response in regular waves FreeMo Computes time domain simulation response of the vessel in various sea states Table 1 Commonly used applications Scroll to the bottom of the Project pane as seen in Figure 3 t The Application Data Files section summarizes what data has been produced by applications as the project develops amp The project files created so far can be saved by clicking Save at the bottom of the Project pane t Alternatively individual project panes can be saved by clicking File Save t The entire project including all open panes can be saved by clicking File Save All Tutorial 1 Creating a new ShipMo3D project ShipMo3D Tutorials INTE or propemners Output Number of
40. t OBJ file was imported that consists of a poorly conditioned box shaped geometry as shown in Figure 23 24 Tutorial 5 Fixing a poorly conditioned mesh ShipMo3D Tutorials File Edit View Curve Surface Solid Mesh Dimension Transform Tools Analyze Render Help Command _DocumentProperties Page to display Render Render RenderDetails Mesh Units PageUnits Dimensions Default Grid Notes Summary Linetypes WebBrowser Mesh Command Command ShadedViewport Command Shade 3 pes Shade settings DisplayMode Shaded DrawCurves Yes DrawWires No DrawGrid Yes DrawAxes Yes DeGSoXOO 0s PD AesB 680 080000 59 GE end 7 Near V Point V Mid ibe De e 7 Tan Quad 7 Knot Project B STrack C Disable CPlane x1564 y 118 BiDefautt Snap Ortho Planar Osnap Record History Qai eJ e I doeAouo US xv 9 E ERe amp SS7lD Figure 23 The poorly conditioned mesh imported in Rhino3D 3 Assessing the mesh s condition t A polygonal mesh is a discretised geometry Continuous and curved geometry are approximated by discretising it into small linear surfaces called polygons or panels t ShipMo3D uses the discretised surfaces to build the potential flow solution as well as for numerically integrating fluid pressures over the geometry s surface so a poor mesh will result in poor numerical results t The hallmark aspects of a poorly conditioned mesh are polygons with large aspect ratios polygons that
41. t PanelHull in the Save Run and Viewing of Results section This will open up a new pane titled Plot PanelHull 22 Tutorial 4 Defining hull geometry with an existing mesh ShipMo3D Tutorials In the Shading and meshing section of this new pane check to the Show panel outlines checkbox This will show the outlines or edges of each panel This provides a graphic representation of the resolution of the mesh r f the mesh has no degeneracies or holes the paneling process is done t The produced mesh should resemble the one found in Figure 22 Figure 22 The paneled hull of the Rhino3D generated mesh 23 Tutorial 5 Fixing a poorly conditioned mesh 1 Tutorial overview This tutorial covers e Assessing the condition of an existing mesh file Regenerating geometry using continuous surfaces e Producing new mesh from continuous surfaces 2 Importing a mesh in Rhino3D t This tutorial makes use of the Rhino3D software which is primarily a surface modelling tool though other programs may be used instead e Launch the Rhino3D software from the Windows start menu tr Rhino3D will ask for a choice of Startup Template e choose the Large Objects Meters template and click Open t Rhino3D can import NURBS geometry models solid geometry models and polygonal mesh geometry models e Click file import and navigate to a polygonal mesh geometry file t n this case a Wavefron
42. tailed in the ShipMo3D User Manuals DSA also offers training and support services to cover more topics and assist with specific needs Each tutorial assumes that all prior tutorials have been completed and some tutorials build upon progress made in previous ones While each tutorial focuses on a different function they are designed to be easily modified to explore the influence of different parameters and functions available Tutorial 1 Creating a new ShipMo3D project 1 Tutorial overview This tutorial covers e Creating a simulation project e Overview of ShipMo3D application based work flow 2 Creating a new project To begin creating and editing a simulation a project must be created Open ShipMo3D by clicking on the ShipMo3D icon from the Windows Start Menu is o In the newly opened ShipMo3D window create a new project by clicking File New Project ts A new project pane with title tab Project appears The signifies this pane has unsaved changes t Only one project can be open at a time amp Fill out the project information in the ShipMo3D Project section of the pan as shown in Figure 1 Set Project directory to the directory where project files will be stored Specify a unique Project name Set Default filename prefix which is used to provide unique file name prefix to the various project files created Set Default label which is the title label used in output files O Do not change
43. the Include diffraction computations check box V As a first run it s a good idea not to include diffraction computations This is done in order to iterate quickly through the radiation computations It s likely that the geometry will exhibit irregular frequencies which need to be dealt with before completing a final run that includes wave excitation loads t When an acceptable wave radiation effect solution is obtained wave diffraction computations will be enabled which 33 Tutorial 6 Computing wave radiation and excitation ShipMo3D Tutorials will enable the computation of wave excitation loads for the vessel File Edit Application Wet panel hull input file CAShipMo3D Tutorials simpleVessel simpleVesselWetPanelHull bin Ship Radii of Gyration for Non dimensional Hydrodynamic Coefficients E Use default values Roll gyradius m 3 8 Pitch gyradius m 5 8 YawGyradius gyradius m 8 amp 2 Options for Computing Hydrodynamic Coefficients Use default values Encounter frequencies for radiation computations rad s Enc freq rad s Range or array Min Max Increment Removed enc freqs rad s Enc freq rad s Add row Delete row Longitudinal mode condition limits Enc freq rad s Condition limit 0 0 100000 0 14 0 100000 0 Add row Delete row Lateral mode condition limits Enc freq rad s Condition limit Making panels tor back patch wet Making panels for front patch wet Panelling dry hull Making panels
44. uence on frequency domain RAO predictions This step requires the reader to have completed Tutorial This tutorial covers e Adding a skeg appendage e How manoeuvring models which includes appendages affect frequency domain RAO predictions 2 Adding a skeg amp In the Ship Appendages section of the BuildShip pane right click the Skegs folder and select Add skeg Right click the newly added skeg and select Edit skeg amp In the Skegs member window that opened click Add row twice two add two rows amp Fill in the skeg geometry information as shown in Figure 45 Click OK 40 Tutorial 9 Adding appendages ShipMo3D Tutorials Input data for skeg Single or pair Label Key Station yRoot m 10 0 0 2 0 0 0 Include added mass Drag coefficient method Wake fraction Roll velocity ratio zBlRoat m Span m Dihedral deg 0 0 1 0 90 0 0 0 3 0 90 0 0 0 1 0 Figure 45 Editing the skeg geometry t The fully appended vessel model can be visualized in ShipMo3D amp In the Save Run and Viewing of Results section of the BuildShip pane click Plot Ship t n the newly open PlotShip pane the square box vessel and it s newly created skeg is rendered and should resemble that shown in Figure 46 50 Tutorial 9 Adding appendages ShipMo3D Tutorials 3 4 6 OG amp Figure 46 A render of the square box with its new skeg Reprodu
45. uency w rad s Heave Pitch Sway Right C Right a 9 e Yaw Rig ht e m Plot size parameters Heave RAO n l a Roll RAO n4 k a o N Width mm 150 Height mm 20d Image format png 0 5 1 0 1 5 f 0 5 1 0 1 5 Wave frequency w rad s Wave frequency w rad s Save Image Pitch RAO ns k a c eo o o i b e Yaw RAO ne k a 0 5 1 0 1 5 A J 0 5 1 0 15 Wave frequency w rad s Wave frequency w rad s Sea direction Sea direction Sea direction Sea direction Sea direction Sea direction Sea direction Sea direction Sea direction 10 Sea direction 11 Sea direction 12 Sea direction 13 Computation time Finished running SM3DSeakeepRegular3 Figure 44 A plot of the square box motion RAOs for a forward speed of 0 0 m s and a relative sea direction of 45 degrees 3 Exporting RAOSs for use with ProteusDS t ShipMo3D can export an RAO database for use with ProteusDS t The database is exported in a ProteusDS compatible format in the form of an ASCII text file amp In the Save Run and Viewing of Results section of the SeakeepRegular pane click ProteusDS Export amp Choose an appropriate file name like squareBoxRAO ini and save it at some file path where it can later be retrieved 48 Tutorial 9 Adding appendages 1 Tutorial overview This tutorial will guide the reader through adding a skegs appendage in the BuildShip application and demonstrate the skeg s infl
46. ullLine end patch begin patch label front patch normalRanges 1 0 1 0 1 1 0 1 0 1 0 begin hullLine station 0 0 yOffsets 0 0 zOffsets 0 2 end hullLine begin hullLine station 0 0 yOffsets 10 10 zOffsets 0 2 end hullLine end patch end patchHull3 20mx20m x2m box PatchHull input 53 Appendix B PatchHull file format 1 Anatomy of the box patch hull file t The first line of the text file is begin patchHull3 This defines the beginning of the patch hull file The end of the patch hull file is defined using end patchHu113 at the end of the file t The following two lines assign a label to the patch hull and define the hull s length and number of stations patchHull3 block begin patchHull3 label box lengthData 20 2 end patchHul13 t Individual patches are defined within the begin patchHull3 block using begin patch which is similarly ended using end patch t Each patch is assigned a label and a set of surface normal ranges t The normal ranges define the minimum and maximum surface normal X y Z component ranges If a surface normal violates these limits a warning message will be provided to the user If the normal range limits are set to 1 0 and 1 0 they ll never be violated t Hull lines used to define the surface patch are defined within the patch block For example the Side patch is defined as Patch block begin pathHull3 begin patch label Box Side Patch normalRanges 1 0 1
47. un button was pressed a binary file was produced as output called squareBoxShipFor MotionDB bin and stored in the project directory This file includes a database required for the computation of ship motions amp In the Ship parameters section of the SeakeepRegular pane select the squareBoxShipForMotionDB bin input file as shown in Figure 42 45 Tutorial 8 Computing RAOs ShipMo3D Tutorials simpleVessel Ship File Edit Application Run Output Plot Help Data directory CAShipMo3D Tutorials simpleVessel Filename prefix simpleVessel Input label Box hull analysis Input note Ship Dimensions and Loading Condition Read only Ship length m Station of aft perpendicular Water density kq m3 Draft of baseline at midships m Trim of baseline by stern m KG height of CG above baseline m Correction to GM metacentric height m Number of rudders Number of propellers Number of azimuthing propellers Ship parameters Ship for motion input file Console Output Window Running 5M3DBuildSh1p3 Input file C X5hipMo3D TutorialssimpleVessel simpleVesselBuildShip3 1np Output file C ShipMo3D Tutorials simpleVessel simpleVesselBuildShip3 out Input file opened Reading input file C ShipMo3D TutorialssimpleVessel simpleVesselBuildShip3 inp Computation time 0 s Finished running 5M3DBuildSh1p3 Figure 42 The SeakeepRegular application s pane highlighting where to specify the BuildShip output binary fi
Download Pdf Manuals
Related Search