Download Maxsurf Hydromax Training PDF

TitleMaxsurf Hydromax Training
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Total Pages20
Document Text Contents
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Hydromax Training



Version 2.0



























© Formation Design Systems 2003

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Hydromax Training

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Hydromax Training
Contents:

1 Overview..............................................................................................................3

1.1 Basic Principles............................................................................................3
1.2 Hydromax.....................................................................................................3

2 Analysis ...............................................................................................................6
2.1 Loading a design ..........................................................................................6
2.2 Different analysis types ...............................................................................6
2.3 Special analysis: what you can do with Equilibrium and Specified

Conditions ....................................................................................................7
2.4 Stability criteria............................................................................................8

3 Setting analysis data ............................................................................................8
3.1 General Data ................................................................................................8
3.2 Analysis Data (Parameters) .........................................................................8
3.3 Analysis Modifiers.....................................................................................13

4 Interaction with MS office ................................................................................14
5 Saving your work ..............................................................................................14
6 Other… ..............................................................................................................14
7 Tips and Tricks: .................................................................................................15

7.1 Formatting the loadcase .............................................................................15
Example Applications ................................................................................................21
8 Inclining experiment..........................................................................................22

8.1 General inclining experiment procedure ...................................................22
8.2 Example inclining experiment results .......................................................23
8.3 Simulating an inclining experiment with Hydromax................................24

9 External Forces and Moments...........................................................................28
9.1 Hydromax – Vertical force balance...........................................................28
9.2 Applying vertical forces ............................................................................28
9.3 Positive and negative forces ......................................................................28
9.4 Free surface moments ................................................................................28
9.5 Applying pure moments ............................................................................29
9.6 Examples of an applied pure moment .......................................................31

10 Stability When Docking – Analysis using Hydromax......................................33
10.1 Stability analysis based on upright GM only ............................................33
10.2 Stability analysis based on selected stability criteria ................................35

11 Assessment of Vessel Stability (for the non-Naval Architect).........................37
11.1 Using Hydromax........................................................................................37
11.2 Assessing Forces........................................................................................37
11.3 Vertical Force Balance...............................................................................37
11.4 Forces and Moments..................................................................................37
11.5 Equilibrium Analysis .................................................................................39
11.6 Large Angle Stability (GZ or Righting Lever Evaluation).......................39
11.7 Example......................................................................................................42

Tutorials......................................................................................................................45
Tutorial 1: Upright Hydrostatics Analysis ............................................................46
Tutorial 2: Large Angle Stability Analysis ...........................................................49
Tutorial 3: Equilibrium Condition Analysis..........................................................53
Tutorial 4: Specified Condition Analysis ..............................................................56
Tutorial 5: KN Calculations Analysis ...................................................................59
Tutorial 6: Limiting KG Analysis..........................................................................61
Tutorial 7: Longitudinal Strength Analysis...........................................................63
Tutorial 8: Tank Calibrations.................................................................................65

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Define as a longitudinal channel section, with edges on centre line:


If necessary, close and taper ends:




3.2.6.2 External tanks
External tanks may not be modelled in Hydromax. However, it is normally possible
to add "Hull" surfaces in the Maxsurf model, which will enclose the external tanks.
The tanks can then be modelled in Hydromax. Note that these "external" surfaces
will add to the buoyant volume of the vessel.

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Additional box-shaped hull surfaces used to define deck tanks

3.2.6.3 Longitudinal extents of tank bounding boxes
The volumes of tanks are computed by inserting a number of transverse sections
between the longitudinal limits specified in the compartment definition window.
Where the hull surfaces extend beyond these limits, the tanks will be accurately
defined with a large number of sections. However, if the longitudinal extent of the
tank is limited by the surfaces rather than the bounding box, it is possible that there
will not be sufficient sections to accurately define the tank. Such a situation may
arise for the external tanks listed above. In this case, the longitudinal extents of the
tank should be specified just inside the longitudinal extents of the surfaces (1mm
say).

3.2.6.4 Modelling non-buoyant areas
Non-buoyant areas of the hull can normally be modelled with hull surfaces.
However, there are occasions when it is more convenient to use non-buoyant
volumes. These are permanently flooded compartments.

Occasions where it is useful to use non-buoyant volumes include the modelling of
bow thruster ducts on very long vessels. If the vessel is very long, and the thruster
duct is of small diameter, there may not be sufficient sections to model it accurately
(even if you use the maximum of 200 sections for the Hydromax model). In this
case you are better off modelling the thruster duct as internal structure and using
these surfaces to define a non-buoyant volume.

Modelling the thruster duct as a non-buoyant volume has the additional advantage
of being able to specify a permeability, and hence account for the thruster.






Bow thruster tube modelled as two non-buoyant volumes

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7.1.3 Things to watch for:
The method described above will work without any complications for simple tanks
and compartments. However, there are two possible problems, which will occur if
any of them are linked or are defined with boundary surfaces.


7.1.3.1 Linked Tanks:
If you have linked tanks, before copying data in MS Excel, you should un-link them
by simply filling down the parent's Type into the Type of the linked tanks below it:



Select cells, then right-click to bring up the context menu and select Fill Down:



The Compartment definition window should now look like this:

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Now you can proceed as before using MS Excel to sort the tanks into the desired
order. After you have pasted the sorted compartment data back into Hydromax, you
will need to re-link the tanks by typing Link or L into the relevant Type rows.


7.1.3.2 Boundary Surfaces
Boundary surfaces pose more of a problem, since their data is not copied from
Hydromax to MS Excel. When you re-paste the sorted data back into Hydromax,
the boundary surface data will be lost and you must re-enter it in Hydromax. This
problem has been resolved in Hydromax 9.6.

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