A2 GeniE Semisub Pontoon

7/28/2019 A2 GeniE Semisub Pontoon

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DNV Software GeniE Semi Pontoon Workshop

Revised 12 March 2011

Modelling in GeniE

DNV Software

SESAM User Course in Curved Structure Modelling

Genie Workshop:

Modelling pontoon and lower column

The purpose of this workshop is to create a model intended for both hydrostatic,hydrodynamic and stress analysis. The workshop does not document how to do the actual

analyses; the focus is on how to create the model.

The structure and loads are fictitious, but you will learn the necessary modelling tasks tomake a real structure

The following topics are covered:

Flat and curved plates

Regular and curved beams

Boundary conditions

Finite element mesh control

It is assumed that the user is familiar withstructure modelling (beams and plates using snap to

point modelling techniques). Furthermore, it is

required that the user has basic knowledge on

GeniEs user interface and how the user mayinteract with the model to derive necessary

information (such as length, positions, properties,

display settings and so on).

Detailed guidance is given in the

beginning of the tutorial

The workshop is also accompanied with input filesfor GeniE (Journal file)

You need to make mesh and run analysis to

see results This workshop should be viewed on-line or on

colour print out.

All pictures have been created using paper background

Default viewing settings have been modified

This tutorial has been revised with GeniE version D5.3-06 Your PC should have at least 1 GB RAM and

preferably hardware acceleration supporting OpenGL

Part 0 - General


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Main dimensionsThe main dimensions are as shown below.

Notice that detailed dimensions are not

given; they are documented during the

workshop.

Emphasis has also been put on using different type of commands so that you learnalternative methods for the various tasks you want to do

As a consequence an operation documented herein may be more efficient by using

other commands

Part 0 - General

x

y


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Part 0 General introduction to the workshop

Pages 1-4 Part 1 Design premise

Define the units, material and section types

Pages 5-10

Part 2 Outer hull, regular part one quadrantDefine the regular and parallel part of the pontoon

You will se the symbols to the right that represent start and stop of

beams during modelling.

Notice that the symbol for right mouse bottom click is

different from left mouse bottom click

Pages 11-13

Part 3 Outer hull, transition one quadrantModel the transition part between regular and fore part

Pages 14 - 21

Part 4 Make the fore partCreate the fore front of the pontoon

Pages 22 22

Part 5 Web framesInsert the web frames

Pages 23 27

Part 6 The columnDefine the column including one horizontal deck

Pages 28 35

Part 7 Pontoon stiffenersInsert longitudinal stiffeners

Pages 36 41

Part 8 Web frame stiffenersDefine the vertical stiffeners

Pages 42 45

Part 9 Longitudinal web frameInsert the longitudinal plate and stiffeners

Pages 46 46

Part 10 Make named setsDefine typical structural parts as sets for later use

Pages 47 49

Part 0 General

Click start of beam

1

Click end of beam

2

Use right mouse buttonto activate the contextsensitive menu

3


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Part 11 Make a mesh

Learn how to control the meshPages 50-53

Part 12 Make pontoonCopy the 1/8 pontoon to a pontoon

Pages 54-54

Part 13 Boundary conditionsInsert boundary conditions. If you want to make a more complete structure as shown in

remaining parts you dont insert boundary conditions at this stage

Pages 55 - 55

Part 14 Make pontoonCopy the pontoon to a 1/2 pontoonPages 56 - 56

Part 15 Make the complete structureMake the complete structure by copying the pontoon and inserting horizontal bracings in

between.

Pages 57 57

Part 0 General


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Define units meters and N Start the program and open a new workspace File|New Workspace. Specify name

Semi_pontoon and use the default values for database units. Click OK when done. Notice, if you want FE results in other units than N and m, you need to

change now.

Define materials Use the command Edit|Properties and select Material. Select Create/Edit Material to

give the details for MAT1 (remember to tick Allow edit). Set the material type to

default and click OK when done

Part 1 Design premise


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Define section properties

Section profiles Tbar425x120x12x25, Tbar575x150x12x25 and Tbar885x200x14x35are found from section libraries

Use the command Edit|Properties and select Section. Select Create/Edit section to

start defining the sections. Select Section Library

Find the right section library from Browse and select the library tbar (a library

containing typical Tbar ship profiles)



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You now find the profiles Tbar425x120x12x25, Tbar575x150x12x25 and

Tbar885x200x14x35 The sections are now selected by clicking on Tbar425x120x12x25 and then

LMB+click on Tbar575x150x12x25 and Tbar885x200x14x35

The picture below shows the selection of Tbar425x120x12x25 andTbar575x150x12x25

Click OK and the profiles are

now part of the design premise

Click create/edit section

to modify the imported sectionsor to insert the remaining brace

section



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Define the profiles Brace. You may use mixed units as shown

Define the plate thicknesses Pl12, Pl15 and Pl30 as follows: Use the command Edit|Properties

and select Thickness.

Select Create/Edit Thickness to

start defining the thickness

properties



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The thickness and section properties may now be accessed from the browser. Since the

modelling will start with the outer hull, the plate thickness Pl15 should be set as default.Similarly, the first use of stiffeners will be at a outer hull; you should set

Tbar885x200x14x35 to defaults. Notice also the default symbol that will appear.

Material default has already been set when creating the property


Use right mouse buttonto activate the context

sensitive menu

1

Use right mouse buttonto activate the contextsensitive menu

1


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Specify the mesh settings for automatic mesh creation as follows:

Edit|Rules|Meshing. In addition to default settings tick off for Use second order elements

Round off Mesh Density



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Insert a guiding plane from the command

Insert|Guiding Geometry|Guide Plane Dialogand enter the values as shown.

Give x-value 0 m, number of spacings 8 in each direction (equal length of allspacings) notice that input may be given in several ways

This plane is used asreference when makingthe outer hull andweb frames

Using the view settings Default

display you see the guide

plane

Part 2 Outer hull, regular part

one quadrant


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Insert a polycurve as follows (one half of the pontoon will be modelled initially)

Insert|Guiding Geometry|Poly Curveand define the positions as shown below

Notice you need to click in between

curvature to guide the tangential

This curve will be used to extrude the

hull form

Start polycurve

1

2nd point

23

4

5

6

7

8 9 10

Double click toend polycurve


one quadrant


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Make the outer hull by a extrude operation.

Select the polycurve and select the commandInsert|Plate|Sweep Curve Dialog

The name of the curve is already

defined (since it was selected)

Specify the length and direction

of the extrusion

-40m in x-direction

The outer hull for one half of the

column width is now created


one quadrant


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Copy the guide plane to new positions for reference when creating the transition zone

between curved corners and quadratic hull shape. Select the guide plane, right click and select Copy|Translate

The vector is found by clicking between start and stop positions of the copyvector

Part 3 Outer hull, transition

one quadrant

Click endof copy vector

2

Click startof copy vector

1


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Copy the new guide plane 2.5 meters in negative x-direction.

Select the guide curve, right click and select Copy|Translate and type in vector -2.5m0m 0m

Change the surface normal of the plate

by selecting the plate, right click and

choose Flip Normal


one quadrant


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Make a model curve and guide lines to refer to when creating the transition part between

curved corner hull and quadratic corner hull. Use command Insert Guiding Geometry|Model Curve and click point 1 and 2

First zoom in on model as shown

Click endof model curve

2

Click startof model curve

1


one quadrant


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Insert two guidelines to use when creating the curved transition. Use command Insert

Guiding Geometry|Guide Line Dialog

Repeat the operation by inserting a new guide

line (Curve4) as shown

Make the transition zone by selecting all three curves (the model curve and the twoguidelines), click right mouse button and select Cover Curves

Start line

1

End line

2


one quadrant


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Copy the curved shell to the bottom part using a mirror copy. Select the plate, right

click and choose Copy|Mirror. The mirror position is found by clicking on point 1 while the direction is

found from clicking the vector from point 2 to point 3.

Mirror point

1

Start vector

2

Start vector

3


one quadrant


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Make the remaining part of the transition zone by inserting regular flat plates. Use

command Insert|Plate|Flat Plate Dialog Click on the four points as shown below

Use same technique to insert

the remaining plates as shown

1st corner

1

2nd corner

2

3nd corner

3

4th corner

4


one quadrant


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Make the fore part by using a skin curve technique

Copy the guideplane using Copy|Rotate as shown (select the guide plane and rightclick to access the command)

rotation point 1

vector between point 2 and point 3

specify angle 90 degrees

Insert a guide arc by command Insert|Guiding Geometry|Elliptic Arc

by clicking at the three points as shown

Part 4 Outer hull, fore part

one quadrant

Rotation point

1

Start vector

2

End vector

3

Rotation point

1

Start arc

2

End arc

3


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Insert two more guidelines as shown and copy all three down to the bottom part of

the pontoon:

Select the three upper curves, right click and choose Cover Curves

Repeat the same process for the lower three curves

Select the plate, right click and choose Flip Normal


one quadrant


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Finally make the vertical hull part by skinning between the lower and upper arc

guide. Use command Insert|Plate||Skin Curves First click the bottom curve, then double click the upper curve

Select the new curved plate, right click

and flip the normal


one quadrant

Seen from outside

Seen from inside


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Two different types of web frames will be made, one watertight and one open. The

watertight will be made using a top down modelling approach while the open will be madeusing a bottom-up approach.

Change default thicknessproperty to Pl12.

Insert a flat plate asshown (at x=0)

Select the plate, right click and choose

Divide

Select the superfluous parts and delete them

to trim the plate to the outer hull.

Part 5 Web frames


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Copy the guideplane to the next frame position at x=-5m.

Define the guide lines as shown on the new guide plane and insert plates for each

part (either from insert plate or cover curve operation)

Part 5 Web frames


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Select the corner plates (Pl14 and Pl18), right click and select divide. Then delete the

superfluous parts to trim to hull shape.

Finally, select all plates in the plane, right

click and choose Join. The 6 plates is now

joined to one plate

Part 5 Web frames

Two different web-frames in place


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Copy the web frames as follows.

Select the watertight and copy to x-values -10m, -22.5m -30m, -37.5m, -40m

The plate at x=-47.5 m has been made from inserting a regular flat plate, selecting it, rightclick, choose divide and delete the parts that are outside the hull to trim it.

Part 5 Web frames


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Select the non-watertight and copy to x-values as shown:

You may verify the plate thicknesses by

To go back to normal modelling view, click the paintbrush

Part 5 Web frames


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One quarter of the column will be modelled. The other parts will be a copy of the first

quarter. Start by making guidelines for references when making the plates.

Use command Insert|Guiding Geometry|Guide Line Dialog

Click first in End 1 input field and then on the model as indicated to find thecoordinates

Do the same for End2 and subtract 7.5 meters in y-direction

Select the new guideline and

copy|rotate as follows

Part 6 The column


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Select the guidelines and

copy upwards 1 meterand 4 meters

Copy the upper guidelines

2.5 meters in x and y direction

so that:

Select the outer upper curves,

right click, select divide

and then delete the highlighted lines:

Part 6 The column


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Insert a circle curve as follows using

command Insert|Guiding Geometry|Guide Arc Elliptic.

Select the curve, right click and

choose Divide. Use parameter

0.5, i.e. divide in 2 equal parts.

Insert guidelines as

follows:

Insert the vertical guidelines

at the edges as shown:

Part 6 The column

Rotation point

1

Start arc

2

End arc

3


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Change default plate thickness to Pl30

Insert the vertical plates asshown using either

Insert|Plate|Skin Curves

or

Insert|Plate|Flat Plate

Select the curves as shown,

right click and choose

Cover Curves

Repeat the process for the right curved part

Finally, insert plates for the remaining

vertical parts using Insert|Plate|Flat Plate

Part 6 The column


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Create the upper part of the column by an extrude command 10 meters in vertical z-

direction. Select the curves as shown, and from command Insert|Plate|Sweep CurveDialog

You need to flip the normal on some of the plates to orient them with theplate normal outwards

Part 6 The column

Seen from inside

Seen from outside


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Insert a deck level at elevation +22m

Copy the guidelines as shownupwards 12 meters

Insert new guidelines to form a quadrant

Change plate thickness to Pl12

Insert a plate at elevation +22m, select it,

choose divide and then delete the partsoutside the column such that it is trimmedto the column surface

Part 6 The column


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Define an opening in the deck level +22m

Start by selecting guidelineas shown and divide with length5.5 meters the inner part becomes2 meters

Copy this line and insert a new

in between so that a quadrantis formed

Use command Insert|GuidingGeometry|Fillet Curves andclick on the highlighted lines andspecify radius 1.0

Part 6 The column


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Finally, select the plate, right click, choose divide and click on the curve (itbecomes orange in colour) to divide the plate.

Select the inner part and delete it

Select all parts above pontoon level and copy|mirror such that

Part 6 The column

Seen from insideSeen from outside


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Stiffeners will be inserted at bottom, side and top of the pontoon

Make sure you have section profile Tbar885x200x14x35 as default

Insert one beam as follows using command Insert|Beam|Straight Beam

Flush the beam to inside of the bottom pontoon plate:Select the beam, right click, choose Edit Beam and

select Offset Vector. Click Flush to bottom

Part 7 Pontoon stiffeners

Start beam

1End beam

2


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To check that the beam is connected to the plate, you may doubleclick the plate beneath

the beam.

The display will now show the

topology of the model this

means that the connection

line between the plate and

the beam is shown. In the

picture below the connection

line is selected for

better visibility

Doubleclick the plate again, to get back to normal modelling view.


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Copy the stiffener to locations as shown:

(the fore part of the pontoon depicted)

Select all the three beams, right click andchoose divide. Delete the stiffener parts

outside the for part of the pontoon hull

Change the section default to Tbar575x150x12x25 and insert stiffeners at the top deckusing the same approach as above. Notice that you need to rotate the first stiffener as shown

before you do flushing to bottom (select beam, right click, Edit Beam and Local system)


The stiffeners are now trimmed to the hull surface

The stiffener is rotated


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Stiffeners are now in place

for bottom and top part ofpontoon

(plates are removed for

visibility)

Change default section to Tbar425x120x12x25 and insert one beam as follows:

Rotate and flush the beam so that (rotate 90degrees around local x-axis and flush to bottom)

(plates are removed for visibility)


Start beam

1End beam

2


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Copy the stiffener to positions

Insert horizontal stiffeners in the fore part (only the fore part is shown in the following)

Copy the selected guideline downwards to new position

Select the new guideline, right click and

select Create Beam

Select the beam, right click and rotate 90degrees around local x-axis



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Flush the stiffener to the plate

Select the stiffener, right click, Edit Beam, Offset vector and choose Flush Bottom

Copy the stiffener to positions

The structure now looks

(some plates removed for visibility)



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Insert stiffeners as shown on the watertight web frames.

Start with one beam, orientate correctly (+90 degrees around local x-axis) and flushto the side of the plate. Use profile Tbar425x120x12x25

Insert eccentricities at both end of beams so that it flushes with bottom and top

longitudinal stiffeners. The eccentricities equal (web height + flange thickness) of

long. stiffener.

Part 8 Web frame stiffeners

Eccentricity from flush to plate


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Insert a vertical eccentricity at the top part as shown (vertical down -0.6m and 0.6)

Remember the eccentricity from plate flush)

Copy the vertical stiffener to positions as depicted (first to web frame, select all three

and copy to all watertight web frames):


Some watertight web frames removed for visibility


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Finally copy the vertical stiffeners to last watertight web frame using a copy mirror

operation:

The watertight web frames have now vertical stiffeners:


Notice that local axis

is flipped when mirroring hence no need for manual rotation

Copy to this position also


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Copy one of the vertical stiffeners at the web frame to fore outer hull as shown:


Copy the stiffener

(plates removed for visbility)


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Set default thickness to Pl15.

Insert a flat plate covering the length of the pontoon (Insert|Plate|Flat Plate):

Insert longitudinal stiffeners accordingly Use profile Tbar425x120x12x25

Rotate around local x-axis 90 degrees and flush on this side of plate (flush bottom)

Part 9 Longitudinal web frame

1st point

1

2nd point

2

3rd point

3

4th point

4


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Named sets are created from selecting objects, right click and choose Named Sets

Select all structure from view setting Modelling-Structure Rubberband select as follows

Right click and choose Named Sets

Give the name One_eight_pontoon

Select the longitudinal web frameincluding the stiffeners and give it

set name Longitudinal_web_frame

The named sets are now availablefrom the browser

Click a set to access commands

for visibility

Part 10 Make named sets


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Continue to make sets:

Set name: Stiffeners Hint: Open browser Property -> Sections, then select all properties, right click and

choose Select Objects

Set name: Half_column

Set name: Web_frames

Includes stiffenersand plates



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Set name: Outer_hull

Includes stiffeners and plates

You may create additional set names modelling and results viewing become moreefficient when referring to named sets.



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Use default mesh density 2.5 meters

(i.e. 2 elements between each stiffener)

From browser, right click in mesh panewindow select New Mesh Property

Define a new mesh property Md_defand specify 2.5 meters as max mesh size

Right click the Md_def and chooseSet Default

Part 11 Make a proper mesh of

the 1/8 pontoon


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Create a finite element mesh from Tools|Analysis|Create Mesh (or use short command

ALT+M) Change the display setting to Mesh All

to see the finite element mesh

The mesh is here seen with a shrink factor as

defined under View|Options|Annotation/Diagrams

Set the Shrunken Mesh Factor to 0.9

In the following is described how to ensure a proper finite element distribution from thebottom of the column and upwards:

From browser Set, choose Half_column and short command ALT+S (Show

selection only) to focus this part only

This part needs mesh control


the 1/8 pontoon


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the 1/8 pontoon

Change to view Modelling-structure and insert a feature edge as follows

Make sure the filter feature Edge is activated!

Insert from command Insert|Feature Edge

Select the Feature Edge, right click, select Properties and choose Mesh Property

Make a mesh property that ensures 6 equal elements along a line and apply to the

feature edge

Start edge

1

End edge

2


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the 1/8 pontoon

Copy the feature edge (now including the mesh line setting) to the following

positions:

Make a new mesh (ALT+M), the mesh is now regularin the lower part as desired


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Part 12 Make pontoon

Select all structure, remove the set Longitudinal-web_frame and remember to include the

feature edges and mirror as follows (shown with preview): If you copy with the longituinal_web_frame you will see some warnings, but the

copy operation is succesful (GeniE will not copy over existing structure)

Select all new structure and give it aset name Quart_pontoon

Make a new mesh (ALT+M)


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Part 13 Boundary conditions

Select the guide line as shown, right click and choose Create Support Curve

Depending on what type of analysis you want to perform you decide the boundaryconditions by right clicking the support curve and change the conditions from

Properties (typically fixed, free, supernodes)

Select the support curve an mirror to the other half of the pontoon.

Boundary conditions in place

Shown here: Fixed, Fixed, Fixed, Free, Free, Free

(plates removed for visbility)


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Part 14 Make pontoon

Select all structure remember to include the feature edges and copy using copy mirror as

shown You should not include

the boundary conditions

in the copy operation

Make a new mesh (ALT+M)


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