1    Total mass calculation

Now that the whole ship itself is in place, you are ready for some analysis functionality.

In entity Mass calculation, the mass and the centre of gravity of the whole system will be calculated. These values will depend on the mass and centre of gravity of both light ship weight and cargo objects. The total mass is calculated by the summation of all mass components (entities) one level below entity Mass calculation. The centre of gravity of a system of components is defined as the average of their positions, weighted by their masses.

Parameter name

Dimension

Determined by

Reference

In Class

Mass

[t]

USR: User or system/equation

Mass

Mass calculation

COGX

[m]

USR: User or system/equation

Centre of gravity in X direction

Dimensions

COGY

[m]

USR: User or system/equation

Centre of gravity in Y direction

Dimensions

COGZ

[m]

USR: User or system/equation

Centre of gravity in Z direction

Dimensions

MOMX

[t*m]

USR: User or system/equation

Moment around X-axis

Dimensions

MOMY

[t*m]

USR: User or system/equation

Moment around Y-axis

Dimensions

MOMZ

[t*m]

USR: User or system/equation

Moment around Z-axis

Dimensions

 

Mass = SUM(@QEntity, 1, @Mass) (The result will be the summation of all parameters Mass of the entities one level below.)

COGX = MOMX/Mass

COGY = MOMY/Mass

COGZ = MOMZ/Mass

MOMX = SUM(@QEntity, 1, @MOMX)

MOMY = SUM(@QEntity, 1, @MOMY)

MOMZ = SUM(@QEntity, 1, @MOMZ)

Please note, that you just created 'normal' relations and connected these to the parameters in the entity, because these are going to be used in several Mass entities.

2     Light Ship Weight

Mass Hull

Parameter name

Dimension

Determined by

Reference

In Class

Weight_volume_factor

[t/m^3]

USR: User or system/equation

Weight factor per volume

Mass calculation

 

Mass = Weight_volume_factor*Volume

COGX = (ENTITY#(12).Lpp)*0.5 (assume the centre of gravity of the hull in X direction half of the ship length)

COGY = 0 (amidships)

COGZ = (ENTITY#(12).Dm)*0.45 (assume the centre of gravity of the hull in Z direction at 45 % of the moulded depth)

MOMX = COGX*Mass

MOMY = COGY*Mass

MOMZ = COGZ*Mass

Volume = ENTITY#(13).Volume

Mass Decks

Mass = SUM(@QEntity, 1, @Mass)

COGX = MOMX/Mass

COGY = MOMY/Mass

COGZ = MOMZ/Mass

MOMX = SUM(@QEntity, 1, @MOMX)

MOMY = SUM(@QEntity, 1, @MOMY)

MOMZ = SUM(@QEntity, 1, @MOMZ)

In entity Decks, below entity Mass Decks, you can present a table that contains a copy of parameters (Name$ and Area) of all decks that are defined by the user in entity Decks below Lay out. In addition, the centre of gravity and mass of each deck can be calculated here.

After the first parameter has been put in the table view with the attribute @MULTVAL, you can drag the other needed parameters directly to the table view from the Knowledge Browser.

The number of cases is equal to the number of defined decks by the user in the “Lay out” Entity. We are going to get this information.

Nr = ENTITY#(10).Nr

The first column/case of the table should contain data (Name$ and Area) from the first defined Deck in entity DeckThe second column contains data from the second defined deck, etc.

Name$ = ENTITY#(16, ORCA(1)).Name$

Area = ENTITY#(16, ORCA(1)).Area

When you want refer to a multiple entity, you also have to indicate the QEntityIndex. Quaestor automatically provides an index value in the Quaestor parameter QEntityIndex for each multiple entity. So ENTITY#(xx, 3) refers to the third defined entity Deck. The function ORCA(1) returns the current case number which is now being executed. So for the second column/case in a table, the value of ORCA(1) = 2. When we combine the index with the ORCA() function, like in the Area relation above, the second column of the current table will refer to the area from the second defined deck, etc.

COGX = ENTITY#(16, ORCA(1.X_front) + (ENTITY#(16, ORCA(1)).X_aft))/2

COGY = 0

COGZ = ENTITY#(16, ORCA(1)).Z

MOMX = COGX*Mass

MOMY = COGY*Mass

MOMZ = COGZ*Mass

Mass = Weight_area_factor*Area

As already discussed in the Deck entity, the Weight_area_factor is a bit special. What you want is, that this property is connected to the original value in Deck (of which the value is hidden) but, when modified by the user, the modified value should be used in both the present Mass Decks->Decks entity AND the original entity Decks->Deck. This is done by means of the @SAVEINSOURCE attribute.

Weight_area_factor = ENTITY#(16, ORCA(1)).Weight_area_factor

@MULTVAL
@MODIFY
@SAVEINSOURCE

 

When a user adds or removes a deck, or changes values of an existing defined deck, these adaptations will automatically propagated to the Mass Decks entity.

Mass Bulkheads

Mass = SUM(@QEntity, 1, @Mass)

COGX = MOMX/Mass

COGY = MOMY/Mass

COGZ = MOMZ/Mass

MOMX = SUM(@QEntity, 1, @MOMX)

MOMY = SUM(@QEntity, 1, @MOMY)

MOMZ = SUM(@QEntity, 1, @MOMZ)

Nr = ENTITY#(17).Nr

Area = ENTITY#(17).Area.ORCA(1)

Name$ = ENTITY#(17).Name$.ORCA(1) TODO: dit levert een foutmelding in Quaestor

COGX = ENTITY#(17).X.ORCA(1)

COGY = 0

COGZ = (ENTITY#(17).Z_bottom.ORCA(1) + ENTITY#(17).Z_top.ORCA(1))/2

MOMX = COGX*Mass

MOMY = COGY*Mass

MOMZ = COGZ*Mass

Mass = Weight_area_factor*Area

Weight_area_factor = ENTITY#(17).Weight_area_factor.ORCA(1)

@MULTVAL
@MODIFY
@SAVEINSOURCE

Please note the difference with the previous section, in which a table was created referring to values within multiple entities. For the bulkheads we have created one table and refer to values within the table of another singular Entity!


3    Mass Cargoes

In entity Cargoes you will enable the user to create a table with a number of cargo objects. For each object, the user has to provide a name, COG and mass.

MOMX = COGX*Mass

MOMY = COGY*Mass

MOMZ = COGZ*Mass

As explanation to the user, you can include a schematic picture that depicts the used coordinate system within this configurator.

 


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