intermediate fea with open source software (preview)

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Moment on Nozzle Natural frequency

Non-linear Contact Thermal

- by Dharmit A. Thako

Finite Element Analysis usingOpen source SoftwareI n te

rm e d i a te



Intermediate Finite Element Analysiswith

Open Source Software

First Edition



Intermediate Finite Element Analysis wit

Open Source SofwareFirst Edition

Dharmit Takore, CPEng, RPEQ

Moonish Ent. Pty. Ltd.

Brisbane, QLD, Australia

Moonish Enterprises Pty Ltd

GPO Box 1299, Brisbane, QLD 4001, Australia

2014



Credits and Copyright

Written by: Dharmit Takore

[email protected]

Publisher: Moonish Ent. Pty. [email protected]

http://engineering.moonish.biz

Graphic Design / Layout: Lomesha Takore

[email protected]

Edition 1 ©2014 Dharmit Takore

No part o this publication may be reproduced, stored or transmitted in any orm or by any means, electronicmechanical or otherwise, without prior written consent rom the publisher, except or the inclusion o briequotations in a review. You may store the pd on your computer and backups. You may print one copy o thisbook or your own personal use.

Disclaimer: Te inormation contained in this book is based on the author’s experience, knowledge andopinions. Te author and publisher will not be held liable or the use or misuse o the inormation in this book

mailto:[email protected]


http://engineering.moonish.biz/



http://engineering.moonish.biz/





oMy wie,

Our beloved son

&

Open Source Sofware



About the Author

Dharmit Takore is the Director o Moonish Enterprises Pty Ltd at Brisbane, Queensland, Australia. Hepractices as a Mechanical / Piping Engineer in Queensland. He received his Bachelor’s degree rom BirlaVishwakarma Mahavidhyalaya, Vallabh Vidhyanagar, Gujarat, India which was affiliated with Sardar PatelUniversity. He started his engineering career as a young Graduate in Larsen & oubro – Sargent & Lundy,Vadodara. He came to Australia or urther studies and settled here. He received his Registered Proessional

Engineer in Queensland (RPEQ) recognition early in his career and subsequently obtained his CharteredProessional Engineer (CPEng) as a Mechanical / Piping Engineer.

Dharmit has broad interests, which include finite element analysis, design, optimization and Open Sourcesofware. He is a member o ASME, Engineers Australia and Board o Proessional Engineers in Queensland.



able o ContentsForeword

Tis book is written or Tis book is not written or

What are the steps in Finite Element Analysis

Study Cases xParametric Modelling in Salome or Geometry and Mesh generation Combining element types in a single FE Analysis Non Linear Material Analysis Contact FE analysis Modal Analysis Termal Analysis x

Parametric Modelling o a Pressure Vessel Geometry Step 1: Description o the problem Step 2: Input values or the FE analysis

Step 3: Parametric Modelling by direct editing o .py file Step 4: Meshing using Notebook Change Parameter in Notebook Summary

Adding Moments to a ace in 3D model Step 1: Description o the problem Step 2: Input values or the FE analysis Step 3 and 4: Generating Geometry by Parametric Modelling and editing mesh Step 5, 6, 7, 8 and 9: Reusing .comm file rom Case9 and editing it Step 10: Run the analysis

Step 11: Post Processing o the Results Summary

Combining Element types in a single FE Analysis Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Generating command file by hand Step 10: Run the analysis


Non-Linear Material FE Analysis Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry



Step 5, 6, 7, 8 and 9: Modiying comm file created by Efficient Step 10: Run the analysis Step 11: Post Processing o the Results Summary

Non-Linear Material – Real Curve FE Analysis

Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Modiying comm file created by Efficient Step 10: Run the analysis Step 11: Post Processing o the Results Summary

Non-Linear FE Analysis with Contact Step 1: Purpose o the FE Analysis / Description o the problem

Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Modiying comm file created by Efficient Step 10: Run the analysis Step 11: Post Processing o the Results Summary

Non-Linear FE Analysis with Contact and Non-Linear Material Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis

Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Modiying comm file created by Efficient Step 10: Run the analysis Step 11: Post Processing o the Results Summary

FE Analysis o 3D Plate or Mode Shapes Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry

Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Creating command file by Wizard Step 10: Run the analysis Step 11: Post Processing o the Results Summary

FE Analysis o 1D Beam or Mode Shapes



Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Modiying comm file created by Wizard Step 10: Run the analysis Step 11: Post Processing o the Results Summary

FE Analysis o 2D Plate or Mode Shapes Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Modiying comm file created by Wizard Step 10: Run the analysis


Termal Conduction FE Analysis Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Creating command file by Wizard Step 10: Run the analysis Step 11: Post Processing o the Results

Summary Termal Convection FE Analysis

Step 1: Purpose o the FE Analysis / Description o the problem Step 2: Input values or the FE analysis Step 3: Model Geometry Step 4: Meshing Geometry Step 5, 6, 7, 8 and 9: Creating command file by Wizard Step 10: Run the analysis Step 11: Post Processing o the Results Summary

What will be covered in Volume 3 Using Python or Parametric Modelling and FE Analysis Using Hommard or adaptive meshing Advanced Termal FE Analysis Termo-Mechanical FE Analysis Pipe Stress Analysis



Fluid Structure Integration

Appendix A Other sources o inormation

Appendix B Installing Sofware required or this book

Ubuntu 12.04 Configuration Salome-Meca 2013.2 installation Efficient Install



Fo

— xiii —

Foreword

Afer the success I received by writing my first Book “Finite Element Analysis using Open Source Sofwarereceived many email communications congratulating me and telling me how easy it was to use my book. Reahad ound an easy to use, easy to read and easy to ollow documentation or Open Source Sofware that canused or Finite Element analysis. Some said that they completed the entire book with the exercise within one si

weekend and I doubt i they had taken any sleep in between.Te users o my book were resh graduates rom the university who knew the undamentals and had been usproprietor sofware in their university and now as they were out o university, they wanted to use someththat doesn’t hurt their hip pocket. Others were seasoned proessionals who knew other proprietary sofwarewanted to know how to perorm FEA using Open Source Sofware.

Tis book starts with updated examples in version 11.x or Code_Aster rom previous book. It then goes onadds on advanced analysis.

Tis book is written or

Tose who have a passion or learning Open Source sofware, particularly CAD and FEA sofware. Tis boowritten or those who are new to sofware like Salome and Code_Aster.

I you are having trouble understanding where to start with Salome and Code_Aster, this book is written or I you are having troubles understanding the computer translated Code_Aster User Documents (which are ricinormation), this book is written or you. I you want easy reerence to 75% o FEA problems that are encountby engineers in day to day lie and want to do that by Open Source Sofware, this book is written or you.

Tis book is or those who don’t want to waste their time in finding tutorials online and trying to make logical sequential sense. Tis book starts with a very basic introduction o what to do to perorm FE Analysis, and twith each new Chapter, it introduces new concepts in an easy to understand ormat. I you want to learn ho

do FE Analysis with Open Source sofware in a week’s time, than this book is or you.

Tis book is not written or

I you are advanced user o Salome and Code_Aster and afer reading the able o Content you can say to yourthat “the inormation covered in this book is something that I already know”, this book is not or you.

Tis book is also not written or someone who does not know what Finite Element Analysis is. FE Analysis, undamental, should be known to the user o this book.

I you are a beginner, it is advised that you purchase our first book “Finite Element Analysis with Open Sou

Sofware” where you will be able to gain more insights into the undamental analysis that can be done with SaloMeca and Code_Aster.

Once you are amiliar with those concepts, this book will be easy to ollow. Some o the chapters in this book on the inormation given in the first book. Tough it is not necessary, it is recommended to complete the book beore you start with this one.



nite Element Analysis using Open Source Software

— xiv —

What sofware would you need to ollow through

Operating System used:

1. Ubuntu 12.04

Sofware used or this book are

1. Salome-Meca version 2013.2

2. Code Aster version 11.3

3. Efficient version 0.1.1

All o the above sofware (except latest version o Efficient) are available in CAELinux 2013 DVD so i you hinstalled it, don’t worry about any more installations. I you want to use latest sofware, install the above versor latest versions o these sofware on your computer. Please note that i you install a sofware that is o hig

version than that mentioned above, the screenshots may differ, but the undamental concepts remain the sam



What are the steps in Finite Element A

— xv —

What are the steps in Finite Element Analysis

Tis book does not teach you what Finite Element Analysis is. You are nearly ready i you are amiliar withgeneral orm o Hook’s law which states that “For small deormations o the object, the amount o deormatidisplacement (Dx) is directly proportional to the deorming orce or load (F)”. Te constant o proportionalitthe above equation is the stiffness (k) o the object.

Generally the stiffness o the object is known due to the act that we would have its shape and material properas a given. I not, Either we would be optimising its shape by finding stresses generated in the object due to apploads (e.g. objective o the study can be “optimise web thickness o gussets or optimise thickness o a press

vessel Nozzle saddle”), or we would be checking which material is most suitable or the given object (e.g. objeco the study can be “Can Aluminium alloy be used to reduce the weight o the object?”). So stiffness “k” woulfixed or the given analysis based on shape and material selected.

Te next step is boundary conditions. Any given object has to be sufficiently supported in the real world and will emulate these supports, either there is a fixed support (e.g. bolted or welded joint), sliding support (e.g. sin hub or pipe shoe on structural steel). By applying these boundary conditions o supports, we are providifixing values o displacement. Ten there would be orces applied to the object, either by gravity (sel-weight

by pressure applied on a surace or orce applied on the object. By adding these boundary conditions o loadsare providing / fixing values o orce / load.

Afer all o the above is given to Code Aster (FE analysis sofware o choice or this book), it tries to solve the equawhich will be in matrix orm with the given input values o displacement and orces and obtain displacementthe entire object. Tese displacements (Strains) are converted to Stresses (Stress = Strain multiplied by YouModulus o the material, or elastic case) and are displayed as a coloured model or exported as a table.

Figure on the next page shows general steps to perorm FEA.




— xvi —

In the coming chapters o this book, we will be using above philosophy to carry out Finite Element AnalyInterpretation o results will be lef to the reader.



Stud

— xvii —

Study Cases

Afer Esha learnt how to perorm FEA using Open Source Sofware like Salome-Meca and Code_Aster, she staher proessional career in the same firm that she did her internship. She was happy that John was her mentothe way long. Esha started gaining more experience with Linear Static Finite Element Analysis, and with mexperience she needed less reliance on John’s guidance. Esha started doing her FE Analysis with more confide

Afer several months, John caught up with Esha to find out how she was eeling regarding the use o Open SouSofware or Finite Element Analysis. Esha was very excited to tell John all about her experiences while they or coffee. Ten Esha told John that every now and then a different type o FE Analysis comes to her or whichis not ready yet. She has to pass them to her other colleagues as she is not eeling confident and she is eeling lost. As usual John was listening to her words careully and asked her i he could help. Esha was waiting or Jto say that and she listed the analysis which she elt were a bit tough or her to do.

Parametric Modelling in Salome or Geometry and Mesh generation

Esha said that John had taught her how to “Dump the study” so that i she wants to recreate the geometry

mesh, it becomes easy or her. But what i she wants to change some o the parameters. What i Esha wantgenerate geometry o the Pressure Vessel and Nozzle junction with different PV Diameter and Nozzle DiameWhat i she wants to change the mesh density in the PV Shell thickness or in the Nozzle thickness?

Combining element types in a single FE Analysis

Esha said that sometimes the models are too big and it would really help her i she could combine 3D elementwith shell elements and Beam elements. Tis would make FE Analysis run aster without compromising herresults. Was there a way to do this in Salome and Code_Aster?

Non Linear Material AnalysisEsha said that what John taught her in last book in Chapter 9 or checking against Allowable stress o the matewas sufficient at that time, but she wanted to know i she could put the Graph o the Material Properties in Salor Code-Aster and i the Analysis could take care o checking when the Allowable stress has been reached and the analysis?

Contact FE analysis

Esha said that she was happy to perorm Assembly FE Analysis, but sometimes there is a requirement whereneeds a gap between two parts and that load can only be translated once there is contact between suraces.

there a way to do it in Code_Aster?

Modal Analysis

Sometimes in her career, Esha had come across a FE problem where she needed to find the Natural requenciea given shape o the object. Esha asked John, i it was possible in Code Aster to find out the Natural requencie



Parametric Modelling of a Pressure Vessel G

— 1 —

Chapter 1 - Case12 Parametric Modelling o a Pressure VesselGeometry

John was glad that Esha asked or help when she needed.John said that first he will show Esha, how to perorm aParametric Modelling o the same Pressure Vessel Geometrythat they created in Chapter 9 / Case 9 o previous book. Tistime Esha was the client as she had a specific request and Johnwas the Engineer.



termediate Finite Element Analysis using Open Source Software

— 2 —

Step 1: Description o the problem

John asked Esha, what the exact outcome that Esha was looking or was. Esha said that in previous book in Cha9 John had showed her how to save a Python file rom which she could generate the geometry again and again. editing that file was time consuming and sometimes she made a mistake in entering the data and was conuselooking through series o lines o Python in the “.py” file. She wanted to know i there was an easy way in w

she could just enter the values o the Parameters and Salome could do the modelling and meshing by itsel.John said that Salome indeed was very powerul and the request that Esha made was easily achievable in SaloJohn told Esha that there are two methods in which the request that Esha has made can be accomplished. method is to edit the “.py” file manually, enter additional parameters and use them in the file to generate geomand mesh it. Te second method was to use something called “Notebook” in Salome that stores parameters which can be edited. John will show Esha both o this methods.

Step 2: Input values or the FE analysis

Dimensions o the Pressure Vessel are similar to the previous book Chapter 9.

ID o Cylindrical shell o PV: 2000mm (2m)

Tickness o Cylindrical shell o PV: 10mm (0.01m)

Hal Length o Cylindrical shell o PV: 1500mm (1.5m)

Dimensions o the Nozzle are

ID o the Nozzle: 300mm (0.3m)

Tickness o the Nozzle: 10mm (0.01m)

Projection o Nozzle: 300mm (0.3m)

Step 3: Parametric Modelling by direct editing o .py file

John copied Python file “Case9.py” rom Case9 older and saved it as “Case12.py” in a separate older namedCase12.

Ten John double clicked the file to open it. He told Esha that each and every line in this file is either a code ttells Salome about the geometry and mesh or is a comment. Ten he scrolled down the file till he could see thollowing code.

# -*- coding: iso-8859-1 -*-

###

### This le is generated automatically by SALOME v6.3.0 with dump python functionality

###




— 3 —

Just below the above statements we will write our code or making this file do parametric modelling. Tis cocan be written anywhere in the file, but as these lines o code are or initialising variables that storeinormation the will be used in modelling they should be initialised beore the values are used.

Python code is really easy and i you have done programming with any other language, you will eel Python toa un and easy language.

Tings to remember in Python language:

1. You don’t need to end the statement with a semi-colon “;”

2. Python ends the statement when “Enter” (Carriage Return / Line Feed) is encountered

3. I you are initialising a variable, Variable Name will be on the lef side o the = sign and value will be the right side

4. Mathematical operations have regular meaning and precedence

5. Everything afer “#” will be considered as a comment

With this in mind let’s add variables that will hold inormation or Geometry and Mesh.

Add the ollowing lines:

#########################

#Parameters for Geometry#

#########################

#Pressure Vessel Outside Radius

PV_OR = 1010

#Pressure Vessel Inside Radius

PV_IR = 1000

#Pressure Vessel Height

PV_Height = 1500

#Nozzle Outside Radius

Nozz_OR = 160

#Nozzle Inside Radius

Nozz_IR = 150

#Nozzle Protrusion Length

Nozz_Protrusion = 200

#Height of Cylinder for Nozzle Construction

Nozz_Len = PV_OR + Nozz_Protrusion




— 4 —

#####################

#Parameters for Mesh#

#####################

#Number of Segments for Global Meshing

GlobalSeg = 15

#Number of Segments for Pressure Vessel Shell Thickness Meshing

PVSeg = 5

#Number of Segments for Nozzle Shell Thickness Meshing

NozSeg = 5

###################

#End of Parameters#

###################

Afer adding the parameters that will be used in the creation o geometry and mesh, lets add these in the pythfile.

Find the lines shown below and enter the parameters defined earlier in their respective locations. Parametersentered manually are shown with Red colour.

Cyl_PV_OD = geompy.MakeCylinderRH(PV_OR, PV_Height)

Cyl_PV_ID = geompy.MakeCylinderRH(PV_IR, PV_Height)

Cyl_Noz_OD = geompy.MakeCylinderRH(Nozz_OR, Nozz_Len)

Cyl_Noz_ID = geompy.MakeCylinderRH(Nozz_IR, Nozz_Len)

Vx = geompy.MakeVectorDXDYDZ(1, 0, 0)

Vy = geompy.MakeVectorDXDYDZ(0, 1, 0)

Vz = geompy.MakeVectorDXDYDZ(0, 0, 1)

geompy.Rotate(Cyl_Noz_OD, Vy, 90*math.pi/180.0)

geompy.Rotate(Cyl_Noz_ID, Vy, 90*math.pi/180.0)

geompy.TranslateDXDYDZ(Cyl_Noz_OD, 0, 0, PV_Height / 2)

geompy.TranslateDXDYDZ(Cyl_Noz_ID, 0, 0, PV_Height / 2)

Geom_OD = geompy.MakeFuse(Cyl_PV_OD, Cyl_Noz_OD)

Geom_ID = geompy.MakeFuse(Cyl_PV_ID, Cyl_Noz_ID)

PV_Whole = geompy.MakeCut(Geom_OD, Geom_ID)

#Please note that § is entered here for clarity purpose

# to show that line continues below without any break




— 5 —

# Please do NOT enter § sign in your code.

a3D_Sketcher_1 = geompy.Make3DSketcher([0, 0, 0, PV_OR, PV_OR, 0, §

PV_OR, PV_OR,PV_Height, 0, 0, PV_Height, 0, 0, 0])

Face_1 = geompy.MakeFaceWires([a3D_Sketcher_1], 1)

Revolution_1 = geompy.MakeRevolution(Face_1, Vz, 270*math.pi/180.0)

PV = geompy.MakeCut(PV_Whole, Revolution_1)

P0 = geompy.MakeVertex(0, 0, PV_Height / 2)

Plane_Vy = geompy.MakePlane(P0, Vy, PV_OR * 5)

Plane_Vz = geompy.MakePlane(P0, Vz, PV_OR * 5)

PV_1 = geompy.MakePartition([PV], [Plane_Vy, Plane_Vz], [], [], §

geompy.ShapeType[“SOLID”], 0, [], 0)

P1 = geompy.MakeVertex(0, 0, 0)

P2 = geompy.MakeVertex(0, (PV_OR * math.sin(45*math.pi/180.0) + §

Nozz_OR) / 2, PV_Height / 2)

P3 = geompy.MakeVertex(0, 0, PV_Height)

By doing above changes we have made geometry creation parametric.

Now to make meshing parametric, find the lines shown below and then we need to make ollowing changes

Global_Mesh_Seg = Regular_1D.NumberOfSegments(GlobalSeg)

Global_Mesh_Seg.SetDistrType( 0 )

Quadrangle_2D = PV_Mesh.Quadrangle()

Hexa_3D = smesh.CreateHypothesis(‘Hexa_3D’)

status = PV_Mesh.AddHypothesis(Hexa_3D)

Regular_1D_1 = PV_Mesh.Segment(geom=PV_SubMsh)

PV_Thk_Seg = Regular_1D_1.NumberOfSegments(PVSeg)

PV_Thk_Seg.SetDistrType( 0 )

Propagation_of_1D_Hyp_on_opposite_edges_1 = §

Regular_1D_1.Propagation()

Regular_1D_2 = PV_Mesh.Segment(geom=Noz_SubMsh)

Noz_Thk_Seg = Regular_1D_2.NumberOfSegments(NozSeg)

By doing above changes we have made the meshing as parametric too.




— 6 —

Now Start Salome Meca and Click File -> Load Script, then select the python file we saved earlier, afer sometime mesh o the Pressure vessel with the dimensions you entered in parameters will be displayed.

Just to check i the python file and parameters are working properly, John entered ollowing parameters(Changes marked in Red)

#########################

#Parameters for Geometry#

#########################

#Pressure Vessel Outside Radius

PV_OR = 1050

#Pressure Vessel Inside Radius

PV_IR = 1000

#Pressure Vessel Height

PV_Height = 1500

#Nozzle Outside Radius

Nozz_OR = 300

#Nozzle Inside Radius

Nozz_IR = 290

#Nozzle Protrusion Length

Nozz_Protrusion = 200

#Height of Cylinder for Nozzle Construction

Nozz_Len = PV_OR + Nozz_Protrusion

#####################

#Parameters for Mesh#

#####################

#Number of Segments for Global Meshing

GlobalSeg = 15

#Number of Segments for Pressure Vessel Shell Thickness Meshing

PVSeg = 5

#Number of Segments for Nozzle Shell Thickness Meshing

NozSeg = 5

#End of Parameters#

###################




— 7 —

And he got ollowing as a result

As can be seen, the thickness o Pressure vessel has increased and the Nozzle diameter has also increased.




— 8 —

Step 3 again: Parametric Modelling by using Notebook

John told Esha that Salome provides a eature called Notebook which is very powerul and that is what we aregoing to use next.

# Description Figure

1

Modelling steps shown here are exactly same as shown in previous book in Chapter 9, with the onlydifference o using Notebook to add parameters. First we will add Parameters to the Notebook andthen use those while generating geometry and mesh.

Open Salome-Meca and start Geometry Module.

2

Click File -> Notebook and a

window will popup as shownin adjacent figure.

Tis is Salome Notebook. Itis blank right now, but we willadd Parameters1 soon.

3

Click below Variable Name andthe field will be ready to acceptVariable Name.

Enter “PV_OR” as the variablename, Press “ab” and the ocuswill move to Variable Value,enter “1010” as the VariableValue.

PV_OR is Outside Radius oPressure Vessel with a value o1010mm.




— 9 —


4

Enter other parameters asshown in adjacent figure.

One thing to note here is the“Nozz_Len” which is given aVariable Value as addition o atwo Variables.2

5We are done adding Geometric Parameters. Click “Apply and Close”

Next we will start generating our geometry.




— 10 —


6

Click New Entity -> Primitives-> Cylinder.

Select the second Option orcylinder, give it a Name “Cyl_

PV_OD” and enter “PV_OR”or Radius and “PV_Height”or Height.

Click “Apply”

For second Cylinder, use “Cyl_PV_ID” as Name and enter“PV_IR” or Radius and “PV_Height” or Height.

Click “Apply”

Use “Cyl_Noz_OD” as Nameand enter “Nozz_OR” orRadius and “Nozz_Len” orHeight.

Click “Apply”

Use “Cyl_Noz_ID” as Nameand enter “Nozz_IR” or Radiusand “Nozz_Len” or Height.

Click “Apply and Close”

7

As can be seen rom the Cylinders that have been created, we need to ranslate and Rotate thecylinders created or Nozzle and place them in their proper location and orientation.

For that we need to create Vectors in all three directions. Ten use Vector in Y direction to rotatethe cylinders or nozzle and then translate them.




— 11 —


8

Click New Entity -> Basic ->Vector.

Select the Second Option orVector, Give it a name “Vx”(Vector in X direction) andenter 1, 0, 0 or X, Y and Z.

Click “Apply”

Next give the name “Vy” andenter 0, 1, 0 or X, Y and Z.

Click “Apply”

Next give the name “Vz” andenter 0, 0, 1 or X, Y and Z.


9

Click Operations ->ransormation -> Rotation.

Select “Cyl_Noz_OD” asObjects, “Vy” as Axis, enter“90” as Angle and Untick“Create a copy” as we do notwant to create a new cylinder.

Click “Apply”

In the similar manner, Rotate“Cyl_Noz_ID” as shown above

as well.Click “Apply and Close”




— 13 —


12

Click Operations ->ransormation -> ranslation.

Select “Cyl_Noz_OD” asObjects, and enter “PV_Hal_Height” or Dz, Untick “Createa copy” as we do not want a newcopy o translated cylinder.

Click “Apply”.

ranslate “Cyl_Noz_ID” asshown above as well.

Click “Apply and Close”.

13

Now we need to use the Pressure Vessel and Nozzle OD Cylinders to generate a Geometry or theOD and then we need to use ID Cylinders to generate a Geometry or ID.

Afer that we need to Remove the ID geometry rom OD geometry to generate a Geometry thatwill be our Pressure Vessel.




— 14 —


14

Click Operations -> Boolean-> Fuse.

Give it a Name “Geom_OD”and select “Cyl_PV_OD” asObject 1 and “Cyl_Noz_OD”as Object 2.

Click “Apply”

Enter a new Name “Geom_ID”and select “Cyl_PV_ID” asObject 1 and “Cyl_Noz_ID” asObject 2.


15

Click Operations -> Boolean-> Cut.

Give it a Name “PV_Whole”and select “Geom_OD” asMain Object and “Geom_ID”as ool Object.





— 15 —


16

Right Click “PV_Whole” inObject Browser and SelectShow Only. Change the modeto “Shading”.

You should be able to seesomething similar to adjacentfigure.

Rotate it, zoom it and see thePressure Vessel shell that youhave created.

Next we will remove excessgeometry as we only need 90degrees o this whole PV.




— 17 —


19

Now we will revolve this ace tocreate the geometry.

Click New Entity -> Generation-> Revolution.

Keep deault Name as“Revolution_1”, Select “Face_1”or Objects and “Vz” or Axis.Enter “270” or Angle, Untick“Both Directions”.


20

Click Operations -> Boolean-> Cut.

Give it a Name “PV” and select“PV_Whole” as Main Objectand “Revolution_1” as oolObject.





— 18 —


21

Right Click “PV_Whole” inObject Browser and SelectShow Only. Change the modeto “Shading”.

You should be able to see

something similar to adjacentfigure.

22

We will need to partition this geometry such that each partitioned solid has only 6 edges.

We need to create two planes that will cut the Geometry in 4 equal pieces. For this we will need tocreate two planes perpendicular to each other and that intersect at the centre o the nozzle.




— 19 —


23

First we will create a point romwhich the plane will pass.

Click New Entity -> Basic ->Point.

Click on First constructor oPoints, give it a Name “P0” andenter co-ordinates as shown inthe adjacent figure.


24

Now we need to create two

Planes with sizes equal to 5times the Diameter o PressureVessel. So we will go back toNotebook and add anotherParameter “OR_x_5” as shownin adjacent figure




— 20 —


25

Click New Entity -> Basic ->Plane.

In the window, Select first

constructor or Plane, give it aName “Plane_Vy”, Select “P0”as Point and “Vy” as Vector.Enter “OR_x_5” as the “Size oplane”.

Click “Apply”

For the second Plane, give it aName “Plane_Vz”, Select “P0”as Point and “Vz” as Vector.Enter “OR_x_5” as the “Size oplane”.


26

Now we partition the geometry.

Click Operations -> Partition.

Give it a Name “PV_1”, select“PV” as Objects and or theool Objects select both Planes“Plane_Vy” and “Plane_Vz” inthe Object Browser by Clickingon them while pressing “Ctrl”.

Make sure Resulting ype is“Solid”.





— 21 —


27

We are not done yet, we still need to partition this geometry urther such that each individual solidswill have only 6 sides.

Next we will create a curve edge that will aid in generating a curved surace to partition thegeometry urther.

At this point in time, Notebook is not able to handle advanced python code like the one we addedmanually in “Case12.py”

(PV_OR * math.sin(45*math.pi/180.0) + Nozz_OR) / 2

so we will just add a simple ormula or Point P2 as PV_OR / 2.5

28Add another variable named“Point_2_y” with the value asshown in adjacent figure




— 22 —


29

Click New Entity -> Basic -> Point.

Click on First constructor o Points, give it a Name “P1” and enter co-ordinates as shown below.

For Point “P1” enter 0, 0, 0 or X, Y, Z -> Click “Apply”

For Point “P2” enter 0, Point_2_y, PV_Hal_Height or X, Y, Z -> Click “Apply”

For Point “P3” enter 0, 0, PV_Height or X, Y, Z -> Click “Apply and Close”

30

Next we generate a Curve romthese three points.

Click New Entity -> Basic ->Curve

Select third constructor orInterpolation, keep deaultName o “Curve_1”, CreationMode should be “By Selection”.

Now or Points we will directlyselect them rom ObjectBrowser by Clicking on themwhile holding “Ctrl” key. Teorder in which you selectthe points is critical as the

interpolation will occur basedon that selection.

Select Point “P1” then “P2” andlast “P3”.





— 23 —


31

We will extrude this “Curve_1”to generate our curved plane.

Click New Entity -> Generation-> Extrusion.

Select first constructor orExtrusion, keep deault

Name o “Extrusion_1”, select“Curve_1” as Base and “Vx” asVector, enter “Nozz_Len” orHeight.





— 24 —


32

Now we will mirror thisExtrusion to orm our secondool object or Partition.

Click Operations ->ransormation -> MirrorImage.

Select third constructoror Mirror, keep deaultName o “Mirror_1”, select“Extrusion_1” or Objects and“Plane_Vy” or Plane Mirror.

Make sure “Create a copy” isticked as we want a copy o theexisting extrusion.





— 25 —


33

Now we partition the geometry.


Give it a Name “PV_2”, select“PV_1” as Objects and orthe ool Objects select Planes“Extrusion_1” and “Mirror_1”.

Make sure Resulting ype is“Solid”.


34

We still need more partitionsto make sure that every acehas 4 edges and every solid has6 aces.

Right Click Cylinder “Cyl_PV_OD” and Select “Show Only”

Click New Entity -> Group ->Create.

Select third constructor orShape ype, change the Nameto “PV_OD”, the Main Shapeshould be “Cyl_PV_OD” andselect the Cylindrical Surace

and Click “Add”


Next do the same or Cylinder“Cyl_Noz_OD” and give it aname “Noz_OD”.




— 26 —


35

Now we partition the geometryone last time.


Give it a Name “PV_Final”,select “PV_2” as Objects andor the ool Objects selectPlanes “PV_OD” and “Noz_OD”.

Make sure Resulting ype is

“Solid”.

Click “Apply and Close”.

Right Click “PV_Final” andSelect “Show Only” and youshould be able to see somethingsimilar to the adjacent figure.

36

Now that the Geometry modelling is complete, we need to create Groups o Faces where we willapply Boundary Condition and Loads.

Boundary Conditions will remain same as Previous Study we did or Pressure Vessel Shell or mosto the part.




— 27 —


37

Click New Entity -> Create ->Group, Select the Tird buttonto Add Face.

Give Name “Dz0” to the bottomace o the shell, “LongPres” tothe top ace and “Norma” to thetwo vertical aces.

Give Name “Press” to the InsideFace o the Pressure Vessel

Shell and also to the Inside aceo Nozzle.

38

We will need a Face Group onthe Nozzle to apply Force.

Give it a Name “Force” andselect 4 aces as highlighted inRed in adjacent figure. Click“Add” to add them and thenClick “Apply”




— 28 —


39

Now we need to create EdgeGroup or Sub Meshes that we

will create in the thickness othe Pressure Vessel and Nozzle.

In the Create Group Window,Select the Second button toAdd Edge.

Add all our edges that we hadselected in previous chapteror the PV Shell and additionaledges that are created due topartitioning o the PV in the

middle o the Length.

40

Also Add our edges as shownin the adjacent figure which areon the Inside o Nozzle and onPV Shell, and give it a Name“PV_SubMsh”.

“PV_SubMsh” should have 12edges in it.




— 29 —


41

Similarly we will create Edgegroup or “Noz_SubMsh” asshown in adjacent figure.

Tere will be 8 edges in “Noz_SubMsh”

42Tis concludes creating Geometry.

Save this file.




— 30 —

Step 4: Meshing using Notebook


1

We spend quiet a long time Modelling the Pressure vessel and Nozzle junction but it is well worth.

Due to the effort spent earlier, we will have to do less effort in Meshing the geometry.

Select Mesh module in Salome-Meca.

2

Click on Mesh -> Create Mesh

Change the Name to “PV_Mesh”.

Click on the Button “Assign a seto hypotheses” and Select “3D:Automatic Hexahedralization”




— 31 —


3

Now in the next window itasks or Number o Segmentsor Global Mesh. We needto define Parameters or theMesh Number o Segments inNotebook.

We will define:

GlobalSeg with Value 15

PVSeg with Value 5

NozSeg with Value 5

4

In the window that popsup, change the Name to“Global Mesh Seg” and enter“GlobalSeg” as Number oSegments.

Click “OK”Click “Apply and Close”




— 32 —


5

Right Click “PV_Mesh” andSelect “Create Sub-Mesh”.

Change the Name to “PV_Sub”, select “PV_SubMsh” orGeometry.

Select “Wire discretisation” orAlgorithm.

Click on the Gear button nextto Hypothesis and Select “Nb.Segments”

6

In the window that pops upchange the Name to “PV TkSeg” and Number o Segmentsto “PVSeg”.

Click “OK”

7

Back to Create sub-meshwindow.

Click on the Gear button nextto “Add. Hypothesis” and Select“Propagation o 1D Hyp. Onopposite edges”.

Tis will ensure that the submesh is propagated throughout

the thickness.





— 33 —


8

Do the same with “Noz_SubMsh” and or the Numbero Segments use “NozSeg”.

Make sure that “Propagationo 1D Hyp. On opposite edges”has been selected.

Click on “Apply and Close”

9

Right Click on “PV_Mesh” andSelect “Compute”.

As can be seen the total numbero Edges, Faces and Volumeshas been reduced.

Number o Volumes reducedrom 54000 to 15000.

Tis will reduce the time takenby Code_Aster to carry out FEAnalysis.




— 34 —


10

We need to create Mesh Groupsrom Geometry Group.

Right Click “PV_Mesh” andSelect “Create Groups romGeometry”.

Click on the Curved Arrownext to Geometry and Select

“Press” rom Object Browser.Click “Apply”

Do the same with “Dz0”,“LongPres”, “Norma” and“Force”

11Tis concludes generation o Mesh.

Save this study.

Change Parameter in Notebook

Now is the real test o Notebook. Once geometry and mesh is generated and the file has been saved, Click onFile -> Notebook and change the parameters and see i the study updates.

For example, change the value o PV_IR rom 1000 to 750 and Click “Update Study”. Salome will be perormithe steps that we carried out to generate geometry and mesh again and when done, it will present the final resOur result is shown below.




— 35 —

John told Esha that using Notebook is very easy and updating geometry and mesh is done by just a click o abutton, but as we noticed, Notebook is not powerul yet and complex ormulas cannot be entered. I you wanenter complex ormulas, you better edit the python file manually.




— 36 —

Summary

John asked Esha to summarise what she learnt by doing this Parametric Modelling. Esha summarised it as be

▶ How to edit a Python file.

▶ How to enter Parameters in Python file.

▶ How to Use Parameters in Geometry and Mesh creation.

▶ How to use Notebook in Salome.

▶ How to add Parameters and its Value in the Notebook.

▶ What are the limitations o Notebook.

▶ How to update study by changing Parameters in the Notebook.

Endnotes

1 Parameters are called Variables

2 You can perorm arithmetic calculations in Variable Value field.



What will be covered in V

— 37 —

What will be covered in Volume 3

Learning new topics rom John, Esha was equipped with new enthusiasm. She started working again andprojects that ormerly she had to orward to her colleagues due to lack o understanding, she could do them wease.

Nearly afer a year, John caught up with Esha to find out how she was eeling regarding the use o new and amore advanced use o Open Source Sofware or Finite Element Analysis. Esha, now a seasoned engineer, John that she was very happy to get new inormation or the help that he had provided her as it helped her in

job. She could do the projects with ease and now was also able to teach others the use o Open Source Sofwa

Ten Esha told John that every now and then an advanced type o FE Analysis comes to her or which she is ready yet. She has to pass them to her other colleagues as she is not eeling confident and she is eeling a bit As usual John was listening to her words careully and asked her i he could help. Esha was waiting or John tothat and she listed the analysis which she elt were a bit tough or her to do.

Using Python or Parametric Modelling and FE Analysis

Esha said that using Python or Parametric modelling was good, but every now and then when she has to re-the study, with more refined mesh, she had to re-do all the steps again. She wanted to know i using Python,she automate the phase o Modelling, Meshing and running the analysis.

Using Hommard or adaptive meshing

Esha had heard about Hommard and that it can be used or adaptive meshing. She wanted to learn how to us

Advanced Termal FE Analysis

Afer learning about two types o Termal FE Analysis, conduction and convection, Esha wanted more. She asJohn i he could teach her advanced Termal Analysis. She wanted to learn Termal Radiation, Termal Analo an Assembly and so on.

Termo-Mechanical FE Analysis

Finding out the temperature o different parts in Termal analysis is good, but there was something missing. Ewanted to learn, how to find out thermal deormation in a part or assembly. She wanted to know i the therStress Strain curve o the material can be attached to thermal and mechanical analysis.

Pipe Stress Analysis

Esha knew that standard Pipe Stress Analysis programs available in the market use Beam model or Stress analShe wanted to learn how to perorm Pipe Stress Analysis using Salome-Meca and Code_Aster.




— 38 —

Fluid Structure Integration

Esha remembered that doing Computational Fluid Dynamics, you can find out the pressure on the boundwalls, she wanted to know i there was a way to project these on to the mechanical parts and carry out FE analyIn short she wanted to learn Fluid Structure Integration o FE Analysis.

Afer listing the above analysis, Esha looked at John who was smiling and had a sparkle in his eyes. John was reto teach Advanced FE Analysis to Esha.

John told Esha that both Salome and Code_Aster were capable o conducting the analysis she asked or and mmore.



App

— 39 —

Appendix A

Other sources o inormation

Tis section is provided here or motivated users who are hungry or more inormation on the sofware coverin this book. Links are provided to the Sofware home page and also to the User Forums. Links provided to twebsites are correct at the time o writing this; i by any chance these links don’t work, just use any search engto find relevant sofware.

1. Salome website http://www.salome-platorm.org/

2. Code Aster website http://www.code-aster.org/V2/spip.php?rubrique2

3. CAELinux website http://www.caelinux.com/CMS/

4. Efficient website http://engineering.moonish.biz/efficient/

5. Salome orum http://www.salome-platorm.org/orum

6. Code_Aster orum http://www.code-aster.org/orum2/

7. CAELinux wiki http://www.caelinux.org/wiki/index.php/Main_Page

http://www.salome-platform.org/

http://www.code-aster.org/V2/spip.php?rubrique2

http://www.caelinux.com/CMS/

http://engineering.moonish.biz/efficient/

http://www.salome-platform.org/forum

http://www.code-aster.org/forum2/

http://www.caelinux.org/wiki/index.php/Main_Page

http://www.caelinux.org/wiki/index.php/Main_Page

http://www.code-aster.org/forum2/

http://www.salome-platform.org/forum


http://www.caelinux.com/CMS/

http://www.code-aster.org/V2/spip.php?rubrique2

http://www.salome-platform.org/




— 40 —

Appendix B

Installing Sofware required or this book

All case studies mentioned in this book can be perormed on a computer that has Ubuntu 12.04 OperatingSystem and which has Salome-Meca and Efficient installed on it.

Ubuntu 12.04 Configuration

Ubuntu 12.04 can be installed on a computer alongside Windows 7 or it can be installed as a Virtual OperatinSystem. Decision o how to install Ubuntu is lef to the readers.

I have installed Ubuntu 12.04 in a virtual environment using Virtual Box.

Configuration o Ubuntu on Virtual Box is shown below



App

— 41 —

Salome-Meca 2013.2 installation

Download Salome-Meca 2013.2 rom their website

http://www.code-aster.org/V2/spip.php?article303

It downloads as a rar file and it is in my Downloads older as shown below.






— 42 —

Now Open erminal and go to Downloads Folder

Enter the command by typing in erminal



App

— 43 —

tar xvf SALOME-MECA-2013.2-LGPL.tgz &&./SALOME-MECA-2013.2-LGPL.run

Follow the prompt and install Salome-Meca 2013.2 in desired location.

Once Salome-Meca installation is complete, a desktop icon will be created which can be double clicked to starSalome-Meca 2013.2

Have un.

I you have any trouble installing the sofware, consult Code_Aster Forums on

http://www.code-aster.org/orum2/vieworum.php?id=26

Efficient Install

Efficient is developed in Java and to run it in Ubuntu, you will need OpenJDK Java 7 runtime.

o download and install it go to

https://apps.ubuntu.com/cat/applications/precise/openjdk-7-jre/

Install it on your Ubuntu installation.

http://www.code-aster.org/forum2/viewforum.php?id=26



http://www.code-aster.org/forum2/viewforum.php?id=26




— 44 —

Download Efficient version 0.1.1 rom http://engineering.moonish.biz/efficient/

On the right hand side latest Efficient version can be downloaded. Click on “Download v0.1.1” and a Java Jarnamed “Efficient_v0-1-1.jar” will be downloaded on your computer. Copy it to a proper location.

o run Efficient, Right Click on “Efficient_v0-1-1.jar” and Select “Open With OpenJDK Java 7 Runtime”





App

— 45 —



Intermediate Finite Element Analysis wit

Open Source Sofware

First Edition

By

Dharmit Takore

CPEng, RPEQ, Brisbane, QLD, Australia

Features:

▶ Builds on the oundation created in Finite Element Analysis with Open Source Sofware

▶ Still using easy to read and understand language loved by many users

▶ Screen shots to help users visualise the procedure and understand efficiently

▶ R l ld pl d i th b k t k fid t th i k l d d th p O