AVEVA E3D 2.1 MASS PROPERTIES TRAINING

CHAPTER 5 5

Mass Properties

5.1

Mass Propert ies Overview

The Mass Properties  utilities are common across all applications in the Design module of AVEVA E3D 2.1. They enable the user to obtain the Weight, Centre of Gravity (C of G) , Surface Area  and Volume  for individual items, parts of the model or the whole model. Whilst the Surface Area and Volume  utilities work in the same way for all disciplines, the weight data and Centre of Gravity data for the Weight and Centre of Gravity   utility is obtained from different sources depending on the discipline.

5.1.1

Weigh t Data

For Piping , Cable Tray , HVAC and Cable, the weight data is stored against individual component weights in the Properties  database. For Piping,   attribute is set on Piping , the ‘wet’ weight, i.e. the pipe full of fluid, can only be calculated if the Fluref  attribute the PIPE or BRAN elements. For Equipment   (EQUI), Volume Model   (VOLM) and Sub Volume Model   (SVOLM) elements, the weight data is stored in the following attributes: 

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Usrweight – Usrweight  – the ‘dry’ weight of the element. A fixed value or an expression may be used. Usrwweight  – the ‘wet’ weight of the element, i.e. the element ‘dry’ weight plus any fluids. A fixed value or an expression may be used. Usrcogravity – Usrcogravity – the co-ordinates of the ‘dry’ centre of gravity from the elements origin, expressed in the frame of reference of the element. Usrwcogravity – Usrwcogravity  – the co-ordinates of the ‘wet’ centre of gravity from the elements origin, expressed in the frame of reference of the element.

 A value or expression must be entered for each attribute on each element after it has been created. For Structural  elements and their soft types, the weight data is obtained by multiplying the volume (net or gross) by the density of the assigned material stored in the Properties  database.

5.1.2 5.1 .2

Centr Ce ntr e of Gravity Data

For Piping , Cable Tray  and HVAC, the C of G position is taken from a Ppoint on the catalogue item whose Purpose attribute is set to COFG. If the Ppoint does not exist then P0 is considered to be the items C of G position. For Equipment  (EQUI), Volume Model  (VOLM) and Sub Volume Model  (SVOLM) elements, the C of G position is stored in the following attributes: 

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Usrcogravity – Usrcogravity – the co-ordinates of the ‘dry’ centre of gravity from the elemen ts origin, expressed in the frame of reference of the element. Usrwcogravity – Usrwcogravity  – the co-ordinates of the ‘wet’ centre of gravity from the elements origin, expressed in the frame of reference of the element.

 A value or expression must be entered for each attribute on each element after it has been created.

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5.1.3

Acc uracy of Mass Propert ies

The mass properties for Structural   elements are calculated by the AVEVA E3D graphical engine and its interpretation of the geometry. The accuracy of this calculation is defined by the graphics settings. Selecting VIEW > Settings > Graphics loads the graphics settings form. Selecting the Representation tab shows the representation settings. The accuracy of the mass properties calculation is influenced by the Ar c To ler anc e setting. The default setting for arc tolerance is 1mm. The minimum arc tolerance that may be defined is 0.1mm.  Arcs within AVEVA E3D are approximated as a series of faceted edges. Reducing the arc tolerance increases the number of faceted edges that must be considered. It will also improve the accuracy of the result. The user must make a judgement between calculation speed/system performance and the degree of accuracy required when setting the Arc Tolerance value.

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5.2

Weight and Centre of Gravit y

Selecting TOOLS > Mass Properties > WeightCofG  displays the Weight and Centre of Gravity form. The upper section of the form allows the user to select the elements to be considered in the calculations. The  Add buttons allow the user to populate the grid in the Selected Elements  area of the form. The top  Add button allows the user to add elements using the method selected in the adjacent textbox. The Add El emen ts options list provides the following element selection methods:

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Current Element  – this option adds the Current Element to the list. Element Members  –  this option adds all members of the Current Element. Members with Tubing  – this option adds all members of the Current Element that contain elements of the type TUBI (implied tube). Current Collection  – this option adds the current collection (if one exists). Graphical Pick  –  this option allows the user to select elements from the graphical display. Graphical Selection  – this option uses the current graphical selection. Within Area – this option allows the user to select an  Area from the 3D view. Within Volume of CE – this option adds all elements that fall within the bounding box of the current element.

The lower  Add button on the form allows the user to add elements using the Named Element textbox adjacent. CE may be entered here as a valid name.

 The Within Area option has been designed to use AREADE elements. These elements are currently only used for the Room Design application in AVEVA Marine and in AVEVA Plant Nuclear Applications.

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 AVEVA Everything3D™ (1.1) Model Utilities TM-1802 Once the Selected Elements   grid has been populated, right clicking in any part of the grid displays a pop-up menu which has the following options: 

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Remove Selected Elements(s)  –  this option removes all selected elements from the list. Remove all Elements  –  this option removes all elements from the list. Enhance in 3D View  –  this option highlights all   the elements in the list in the 3D view. Unenhance in 3D View  –  this option will un-highlight all elements in the list in the 3D view. Navigate To  – this option is a toggle. When on, indicated by a tick to the left of the option, clicking on any element in the list will navigate to it in the Model Explorer. Export to Excel  – this option enables the Selection  grid to be saved to Excel. The user is presented with a standard windows dialogue box to choose the filename and location for the Excel file. …

Print Preview

 – this option produces a print preview of the Selection grid.

…

Initially the Selection grid has two columns, i.e. Type and Name. When the calculations are complete the grid displays additional columns for Weight   and C of G. The Grid can be filtered and sorted in the same manner as any AVEVA E3D grid gadget. The Settings  area of the form enables adjustments to be made to the Weight and Centre of Gravity  calculations via a series of options list and textboxes. The Wet/Dry option list enables the selection of the Wet Weight or Dry Weight  to be used in the calculations.

The Negatives   options list enables the user to select whether or not negative  geometry (e.g. end preparations, holes, etc.) will be considered in the calculations. The options are: 

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Consider (net) – this option allows for negative geometry and produces the most accurate result. The data returned is appropriate for determining as-built weights for loading calculations, transport planning, etc. Ignore (gross) – this option ignores the effect of negative geometry. The data returned is appropriate for material cost estimating, etc. Ignore (rough) – this option is similar to the Ignore (gross) option, however, this calculation makes a number of simplifications (basic arc tolerances, less iterations of surface smoothing of complex primitive configurations, etc.). It is quicker calculation and is a useful option for models with large amounts of data or very complex geometry.

The Weight Of  option list allows the user to specify whether the calculations will apply to the Element Only or  Al l Memb ers   associated with the element. For example, consider a section  that owns several fittings. Selecting  Al l Member s   would include the geometry of  the section and the fittings in the calculations. Selecting Element Only  would consider the section only  and ignore the fittings. When calculating mass properties the system uses the Representation Mass  value which can be set in the Representation Level textbox on the Weight and Centre of Gravity  form or by using the Representation tab on the Graphic s Settin gs  form.

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The Refresh button adjacent to the Representation Level   textbox will refresh the level setting if it is changed on the Graphics Settings  form. Representation Mass is similar to other representation settings for different drawing levels of detail. For example, a very simple shape may be represented at Level 1, whereas more complicated geometry may be represented at Level 6. A more simplistic shape representation will return a mass property more quickly, though it will be less accurate than the result obtained when a detailed representation is considered. The CofG wrt  textbox is used to calculate the centre of gravity of an element with respect to another, the default is /* (World) coordinates. The user can input, for example, an element Name and the calculations will use this for the list of individual Centres of Gravities. If the user changes the CofG wrt  value on pressing the Return key the total Centre of Gravity will be refreshed. To refresh the individual Centre of Gravities displayed in the Selected Elements grid the calculation must be performed again. Once the appropriate settings have been chosen the calculations are made by selecting the Appl y  button. If all elements are valid, the total Weight and Centre of Gravity  coordinates are displayed in the appropriate textboxes. The individual element data is displayed in the Selection  grid.

 The Weight and Centre of Gravity use the current session units for Mass and Distance respectively, as defined in the units setting form.

If a weight or C of G cannot be determined for a selected element, i.e. a component weight cannot be found (Piping, Cable, HVAC), the Matref   attribute is not set (Structural) or the user data has not be entered (Equipment), an error message is returned for that element.

5.3

Surf ace Area

Selecting TOOLS > Mass Proper ties > Ar ea displays the Surface form . The top part of the form, including the Selected Elements grid, looks and functions in a similar way as the Weight and Centre of Gravity  form described earlier, with the following differences. 

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The  Add Elem ent s   options list does not contain the Within  Ar ea option. The Selection  grid, when populated and the calculation run, displays a column for the Surface, rather than Weight   and CofG.

The Settings  area functions in the similar way to those described previously for the Weight and Centre of Gravity   form. Except instead of the CofG wrt text box the user is presented with a Units option list. Here the units displayed for surface area can be changed between square mm , cm , m , inches  and feet . This works independently  of the current session distance units. Clicking the  Appl y   button calculates the Total Surface area, displaying the result in the Total Surface textbox and populating the Surface column in the Selection grid for each element.

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5.4

Volume

Selecting Tools > Mass Properties > Volume  from the main menu displays the Volume form . The top part of the form, including the Selection grid, looks and functions in a similar way as the Weight and Centre of Gravity form described earlier, with the following differences. 

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The  Add Elem ent s  options list does not contain the Within  Ar ea option.  After running the calculation the Selection  grid displays a column for the Volume rather than Weight  and CofG.

The Settings   area options functions in the similar way to those described previously for the Weight and Centre of Gravity  form. Except, instead of the CofG wrt text box the user is presented with a Units  dropdown list. Here the units displayed for surface area can be changed between cubic mm , cm , m , inches   and feet . This works independently  of the current session distance units. Clicking the Appl y  button calculates the Total Volume, displaying the result in the Total Volume textbox and populating the Volume column in the Selection  grid for each element.

5.5

Using the Mass Properties Utility  A Worked Example  –

Exit AVEVA E3D then re-enter AVEVA E3D as a Structural Designer using the details provided by the Trainer, for example: Project: Training (TRA) Username: A.STEEL MAN Password: A MDB: A-STRUCTURA L Module: Model

Select the Structures module from the quick access toolbar to enter the Structures  application.

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This worked example utilises the STRU PIPERACK   to demonstrate the functions of the Mass Properties utility.  Add the STRU PIPERACK , in ZONE ZONE-STRUCTURAL-AREA01, to the 3D view. Select the Piperack either from the model explorer or using a selection fence. From the Properties Grid change the Material field to S355J0 Steel .

5.5.1

Calcu latin g Weight and Centr e of Gravity

Select TOOLS > Mass Prop erties > Weight Cof G display the Weight and Centre of Gravity fo rm . With the STRU PIPERACK   as the CE, select Element Members from the Add El emen ts  options list and click the Add  button. Each FRMW  within the STRU  is listed in the Selected Elements grid. Note that the elements are highlighted in the 3D view. Leave the Settings  area of the form at the default values then click the Appl y  button. The Selected Elements   grid now contains two further columns listing the Weight  and CofG coordinates for each FRMW. Note the Total Weight  and Centre o f Gravity   at the bottom of the form for all FRMWs   and the axes aid graphically showing the Centre of Gravity in the 3D view.

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 AVEVA Everything3D™ (1.1) Model Utilities TM-1802 In the Settings  area of the form enter J1  in the CofG wrt  textbox and press the Return  key. Note that the overall Centre of Gravity  coordinates have changed but the individual Centres of Gravity are the same. Clicking the  Appl y button updates the individual Centres of Gravity.

Right click within the grid, from the pop-up menu select Remove All Elements  to remove all elements from the Selected Elements  grid. In the Named Element   text box enter /ROW_J-BRACING   and press the Return  key then click the adjacent Add  button.

In the Settings   area of the form enter WORLD  in the CofG wrt textbox and press the Return  key. Leave the other settings at the default values and click the Appl y button. Note the calculated Total Weight . In the Settings  area of the form, enter 2 in the Representation Level  textbox and click the Refresh  button. Click the  Appl y button again and note the calculated Total Weight . The total weight should have increased from the previous calculation. Close the Weight and Centre of Gravity  form. The difference in weights is due to the use of different Mass Representation  levels. In this example Mass Representation Level 2  has utilised simplified geometry   (e.g. no radius at corners of the RHS) when considering the section profile. By contrast, Mass Representation Level 6  utilised more detailed geometry   representation (e.g. radii at corners) when considering the section profile. The geometry at different representation levels is set in the structural profile catalogue. In a similar manner to changing the way negative geometry is considered, the mass representation level provides another tool allowing designers to choose between accuracy of result and speed of calculation.

 Care should be taken with the mass representation level and negative geometry. The designer must consider how the returned information is to be used.

5.5.2

Calcu latin g Surface Area

Change the viewing direction to a Plan North  view. Use the PowerWheelTM to set limits to extents. Using a Wholly Within   selection rectangle, select the eastern mos t  bay of the STRU PIPERACK.

Select TOOLS > Mass Properties > Area  to display the Surface form. Select Graphical Selection  from the  Ad d Elem ent s  option list and click the  Add  button to display the sections from the graphical selection in the Selection grid. Copyright © 2013.  AVEVA Solutions Limited and its subsidiaries.  All rights reserved.

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Change the viewing direction to Isometric N-E  and note the elements are highlighted in the 3D view.

Enter 6  in the Representation Level   textbox, press the Return  key and click the Update button. Leave the other settings in the Settings   area at the default values. Click the Appl y  button. The Selection  grid displays the Surface  area for each individual element and the surface area of all elements is displayed in the Total Surface  textbox at the bottom of the form.

Right click in the Selected Elements  grid and select Remove Al l Elements  to remove all members from the Selected Elements  grid. In the Model Explorer navigate to GENSEC 2 of FRMW ROW_J  of the PIPERACK.  Select Current Element from the Add El emen ts  options list and click the Add  button. This GENSEC owns a number of web stiffener fittings where the bracing members are connected to it. In the Settings   area of the Surface  form select Element Onl y  from the Surface Of  options list. Click the  Appl y button and note the calculated Total Surface area.

Change the Surface of setting to  Al l Memb ers   and click the  Appl y button again. Note the change in the Total Surface value.

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 AVEVA Everything3D™ (1.1) Model Utilities TM-1802 The Total Surface  area calculated using the  Al l Memb ers option includes the area of the web stiffeners, whereas, the Element Only   option ignored the stiffeners and considered the surface area of the section only. Close the Surface form.

5.5.3

Calcu latin g Volum e

Select TOOLS > Mass Properties > Volume from the main menu to display the Volume form. In the Model Explorer navigate to FRMW ROW_7 of the PIPERACK . Select Element Members   from the  Add Elem ent s option list and click the  Add   button to display the members of ROW_7 in the Selection  grid. Note the selected items are highlighted in the 3D View.

Leave the settings in the Settings  area at the default values. Click the Appl y  button to calculate the volume. The Selection grid displays the Volume for each individual element and the surface area of all elements is displayed in the Total Volume textbox at the bottom of the form.

Close the Volume form.

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Exercise 4 Calculating Mass Properties This exercise adds weight and C of G data to the equipment in Area 01 and then uses the Mass Properties utilities to determine weight, centre of gravities, surface areas and volumes. Navigate to ZONE ZONE-EQUIPMENT-AREA01 and, using the Attributes  form, add the following data to the relevant equipment attributes. Equipment Name

Usrweight

Usrwweight

Usrcogravit y

Usrwcogravity

C1101

15000

16000

E 0 N 0 U 10350

E 0 N 0 U 9900

D1201

3000

3200

E 0 S 2400 D 50

E 0 S 2400 D 50

E1301

2250

3000

E 0 N 3250 D 5

E 0 N 3250 D 5

E1302A

1200

1500

E 0 S 2750 U 55

E 0 S 2750 U 55

E1302B

1250

1550

E 0 S 2750 D 10

E 0 S 2750 D 10

P1501A & B

250

300

E 10 S 605 D 180

E 10 S 500 D 150

P1502A & B

400

475

E 0 S 600 D 275

E 0 S 550 D 250

 The syntax for entering the C of G values is (EA NB UC) where A, B, C are the ENU coordinate values respectively.

Calculate the dry and wet weights and C of G for :PUMP P1501A and note that the obtained values correspond to the input values. Calculate the weight and C of G of different combinations of equipment, with respect to the World and to other elements. Calculate the surface area and volumes of individual pieces of equipment and combinations of equipment.

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