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Finite Element Analysis with

Open Source SofwareSecond Edition

Dharmit Takore, CPEng, RPEQMoonish Ent. Pty. Ltd.

Brisbane, QLD, Australia

Moonish Enterprises Pty LtdGPO Box 1299, Brisbane, QLD 4001, Australia

2014


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Credits and Copyright

Written by: Dharmit [email protected]

Publisher: Moonish Ent. Pty. Ltd

[email protected]

http://engineering.moonish.biz

Graphic Design / Layout: Lomesha [email protected]

Edition 2 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 authors 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]:[email protected]://engineering.moonish.biz/mailto:[email protected]:[email protected]://engineering.moonish.biz/mailto:[email protected]:[email protected]


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o

My wie,

Our beloved son

&

Open Source Sofware


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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 Bachelors degree rom BirlaVishwakarma Mahavidhyalaya, Vallabh Vidhyanagar, Gujarat, India which was affiliated with Sardar Patel

University. 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 ProessionalEngineer 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.


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able o ContentsForeword

What motivated me to write this bookTis book is written orTis book is not written or

What sofware would you need to ollow throughWhat are the steps in Finite Element AnalysisStudy Cases x

Case 1: Getting to know Salome-MecaCase 2: Editing command (.comm) fileCase 3: 1D Finite Element Analysis xCase 4: 2D Frame Finite Element Analysis xCase 5: Axi-symmetric Finite Element Analysis xCase 6: 2D Shell Finite Element Analysis xCase 7: Basic 3D Finite Element Analysis x

Case 8: 3D Finite Element Analysis with Hexahedral Linear MeshCase 9: 3D Finite Element Analysis with Hexahedral Quadratic MeshCase 10: Finite Element Analysis o a Pseudo AssemblyCase 11: Finite Element Analysis o a 3D Assembly

Getting to know Salome-MecaStep 1: Purpose o the FE Analysis / Description o the problemStep 2: Input values or the FE analysisStep 3: Model GeometryStep 4: Meshing GeometryStep 5, 6, 7, 8 and 9: Salome-Meca Linear Static Analysis Wizard

Step 10: Run the analysisStep 11: Post Processing o the ResultsSummaryPS Using Efficient to generate command (.comm) fileChapternotes

Editing command (.comm) fileStep 1: Purpose o the FE Analysis / Description o the problemStep 2: Input values or the FE analysisStep 3: Model GeometryStep 4: Meshing GeometryStep 5, 6, 7, 8 and 9: Salome-Meca Linear Static Analysis WizardStep 8 and 9 again: Manual editing o command (.comm) fileStep 10: Running the analysisStep 11: Post Processing o the ResultsSummaryPS Using Efficient to generate command (.comm) file


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Chapter notes

1D Finite Element AnalysisStep 1: Purpose o the FE Analysis / Description o the problemStep 2: Input values or the FE analysisStep 3: Model Geometry

Step 4: Meshing GeometryStep 5, 6, 7, 8 and 9: Creating command (.comm) file with EficasStep 10: Run the analysisStep 11: Post Processing o the ResultsResultSummaryPS Using Efficient to generate command (.comm) fileChapter notes

2D Frame Finite Element AnalysisStep 1: Purpose o the FE Analysis / Description o the problem

Step 2: Input values or the FE analysisStep 3: Model GeometryStep 4: Meshing GeometryStep 5, 6, 7, 8 and 9: Creating command (.comm) file by using a templateStep 10: Run the analysisStep 11: Post Processing o the ResultsSummaryPS Using Efficient to generate command (.comm) fileChapter notes

Axi-Symmetric Finite Element analysis

Step 1: Purpose o the FE Analysis / Description o the problemStep 2: Input values or the FE analysisStep 3: Model GeometryStep 4: Meshing o GeometryStep 5, 6, 7, 8 and 9: Salome-Meca Linear Static Analysis WizardStep 10: Running the analysisStep 11: Post Processing o the ResultsSummaryPS Using Efficient to generate command (.comm) fileChapter notes

2D Shell Finite Element analysisStep 1: Purpose o the FE Analysis / Description o the problemStep 2: Input values or the FE analysisStep 3: Model GeometryStep 4: Meshing GeometryStep 5, 6, 7, 8 and 9: Writing command (.comm) file by hand


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Step 10: Run the analysisStep 11: Post Processing o the ResultsResultSummaryPS Using Efficient to generate command (.comm) fileChapter notes

Basic 3D Finite Element AnalysisStep 1: Purpose o the FE Analysis / Description o the problemStep 2: Input values or the FE analysisStep 3: Model GeometryStep 4: Meshing GeometryStep 8 and 9 again: Manual editing o command (.comm) fileStep 10: Run the analysisStep 11: Post Processing o the ResultsStep 4 again: Meshing Geometry

Step 5, 6, 7, 8, 9 and 10 again: Salome-Meca Linear Static Analysis WizardStep 11 again: Post Processing o the ResultsSummaryPS Using Efficient to generate command (.comm) fileChapter notes

3D Finite Element Analysis with Hexahedral Linear MeshStep1: Description o the problemStep 2: Input values or the FE analysisStep 3: Model GeometryStep 4: Meshing Geometry

Step 5, 6, 7, 8 and 9: Salome-Meca Linear Static Analysis WizardStep 10: Run the analysisStep 11: Post Processing o the ResultsSummaryPS Using Efficient to generate command (.comm) file

3D Finite Element Analysis with Hexahedral Quadratic MeshStep1: Description o the problemStep 2: Input values or the FE analysisStep 3: Model GeometryStep 4: Meshing Geometry

Step 5, 6, 7, 8 and 9: Efficient WizardStep 10: Run the analysisStep 11: Post Processing o the ResultsSummaryChapter notes

Finite Element Analysis o Pseudo Assembly


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Step 1: Description o the problemStep 2: Input values or the FE analysisStep 3: Model GeometryStep 4: Meshing GeometryStep 5, 6, 7, 8 and 9: Efficient Wizard to generate command (.comm) fileStep 10: Run the analysisStep 11: Post Processing o the ResultsSummaryChapter notes

Finite Element Analysis o 3D AssemblyStep 1: Description o the problemStep 2: Input values or the FE analysisStep 3: Model GeometryStep 4: Meshing GeometryStep 5, 6, 7, 8 and 9: Creating command (.comm) file by using a template

Step 10: Run the analysisStep 11: Post Processing o the ResultsSummaryPS Using Efficient to generate command (.comm) fileChapter notes

What will be covered in Volume 2Parametric Modelling in Salome or Geometry and Mesh generationEditing and Generating Mesh in Salomes Mesh ModuleCombining element types in a single FE AnalysisNon Linear Material Analysis

Sliding Contact instead o GluedModal AnalysisTermal AnalysisVolume 2 Book Promotion - 35% Off

Appendix AOther sources o inormation

Appendix BInstalling Sofware required or this bookUbuntu 12.04 ConfigurationSalome-Meca 2013.2 installation

Efficient Install


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Fo

xiii

Foreword

During my university lie, I had taken Computer Aided Design (CAD) and Finite Element Analysis (FEA) aselective subjects. As a young university student, I was ascinated by the power o computers and the help they provide to obtain results that are easy to understand or a complex simulation. Going rom Drawing boapencils and erasers to CAD with everything on the computer, having multiple revisions o the same drawing

the powerul undo and redo unctionality were one o the journeys that I will never orget.At that time, our university was having education version o AutoCAD (I wont tell the version o AutoCADthat will reveal my age ) or drafing and Solid Edge or Finite Element Analysis. Te only problem was outside university we were on our own. We even didnt have student versions o those sofware to use at hom

What motivated me to write this book

It was not until 2006 that I was introduced to the world o Linux, Ubuntu (in particular) and Open Source SofwI was captivated by the motivation o so many active developers around the world and the effort that they puto develop Open Source sofware. Te only problem I had with Open Source Sofware was that these sofw

even though powerul enough to compete with commercially available sofware, didnt have a reerence manuuser guide or an easy step-by-step guided method on how to use the sofware, starting rom scratch. Selectedsofware do have excellent resources but most open source sofware lack them. Almost all sofware had expethat the user will figure out the way. Tis gap is bridged by so many active users o Open Source Sofware whoon video tutorials and write how-to manuals which are published on the internet. A big kudos to those voluntwho put in their time and effort or Open Source sofware to help others and to me when I started out.

I wrote this book so that someone can pick up this book, start using Salome and Code Aster straight away withhunting or resources on what to do next. I wanted the learning curve to be relatively easy. So I designed this bsuch that the users do a ew exercises, ollowing the step by step guide in this book, eel confident in the procedand then are able to use the Open Source sofware the way they want. I wrote this book or the reason thattutorials on the internet and the videos on websites are scattered and unlinked. I want to help someone to havthe inormation in one single place, in an easy to ollow manner, which will enable them to learn the undameno the sofware in a un and easy ormat.

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 yI you are having troubles understanding the computer translated Code Aster User Documents (which are ric

inormation), 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 dont 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 hodo FE Analysis with Open Source sofware in a weeks time, than this book is or you.


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nite Element Analysis using Open Source Software

xiv

Tis book is not written or

Someone who is an advanced users o Salome and Code Aster, who already knows how to use these sofwknows what their limitations are and what they are capable o. Tis book will be o limited help to you unyou want to gif it to someone who is starting out resh and whom you are mentoring and dont want to ansundamental questions.

I you are the developers o Salome and Code Aster, then I doubt this book will be o any help to you, but i youdevelopers o only Salome or only Code Aster, and want to know what is happening on the other side o the enthen this book might be o use to you.

In short, i you are advanced user and afer reading the able o Content you can say to yoursel that the inormacovered 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.

What sofware would you need to ollow throughOperating 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 0.1.0

Please note that i you install a sofware that is o higher version than that mentioned above, the screenshots mdiffer, but the undamental concepts remain the same.


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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 Hooks 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.


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xvi

In the coming chapters o this book, we will be using above philosophy to carry out Finite Element Analysis o 2D, 3D models o the objects and obtain Displacements, Forces and Stresses. Interpretation o results will beto the reader.


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Stud

xvii

Study Cases

Real world examples are used in this book to describe each Study cases. Not only will this make it interestinwill give users a better understanding o how theory translates to practical analysis or what to do when rubmeets the road.

o make this more interesting a small role play is introduced in this book (at the start o the chapters) in whthe main character Esha is a resh out o University young Engineer who joined a Design firm and was gresponsibility to carry out FE Analysis o calculations that were traditionally perormed by either hand calculatior the Rule o thumb method was used.

A supervisor John is appointed to mentor Esha. John is passionate about the use o Open Source sofwand knows the power they possess. o break the ice, John shows Esha the use o Salome-Meca by giving a vsmall example o a 1m cube with pressure o 1MPa applied on top ace and in another example he shows stregenerated in a cantilever beam with gravity load applied.

Afer showing how easy it is to conduct FE Analysis with Salome-Meca, John shows Esha what the undamesteps to perorm Stress Analysis are and how to replicate them in Salome-Meca and Code Aster.

John asks Esha to conduct FE Analysis o real world examples that will help her in building her capabilities confidence.

With every new example new concepts will be discussed and explained in an easy to ollow ormat.

Case 1: Getting to know Salome-Meca

In this case a very easy FE Analysis o a Solid cubewill be stress analysed. It will be fixed at the bottom ace apressure o 1MPa will be applied on its top ace.

A step by step procedure will be discussed that will take you on a journey rom where you are right nowknowing Salome-Meca better. You will understand concepts o different modules o Salome-Meca viz. GeomeMesh, Aster, Post-Pro etc. You will see how to make a simple geometry and make it ready or Meshing. Youcreate the mesh (i you are ollowing with the book) out o the Geometry. You will understand the Wizard Salome-Meca has and how to enter required parameters. Afer the analysis is complete, you will review the resthat are given by deault, visualise them and try to make sense out o them. Ten you will add a new analysthe same study and see how you can have multiple load cases or the same geometry.

Case 2: Editing command (.comm) file

With the first case, you will be thinking that Salome-Meca can only be used with its limited Wizard Analysis.

in the Second case John will break this thought and show you how to edit the command (.comm) fileto give results and analysis type that you want.

You will understand how to use Salome-Meca Wizard to generate the deault command (.comm) file. How tothis file manually and then conduct the FE Analysis.


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xviii

Case 3: 1D Finite Element Analysis

With this case, John will show how manually calculated results o a simple Pipe Guide which behaves as a cantilbeamare calculated by Salome Meca by the use o 1 Dimensional (1D) Analysis.

John will discuss what should be taken care o in 1D analysis as well as the use o Aster module, which has mpower than the Wizard. You will also learn how to use Eficas to generate command (.comm) file.

Case 4: 2D Frame Finite Element Analysis

Tis case takes 1D analysis carried out previously and adds one more dimension to it. A 2D frameis built Analysed in this study.

John shows how to model a 2D rame, how to mesh it and finally how to perorm FE analysis using Salome-MeAster module. You will also learn how to add a Rectangular Hollow Section (RHS) to the study and how to obresults in ext file along with in MED file.

Case 5: Axi-symmetric Finite Element Analysis

Te next logical step in perorming FE analysis is Axi-symmetricanalysis. Tis is what will be discussed insection o the book.

How to generate 2D geometry or Axi-symmetric model o a Pressure Vessel. John will ask Esha to demonstthat the stresses generated in the hemispherical head is hal that o a cylindrical shell by analysing a Pressure Veshell and head junction using Axisymmetric model. I you are ollowing along you will get a hands on idea oway Axi-symmetric analysis works and how Salome-Meca Wizard takes care o the minor details o the analYou will also learn how to create a Quadrangle 2D mesh and how to insert Sub-mesh.

Case 6: 2D Shell Finite Element Analysis

Some o the complicated 3D geometries are better modelled as 2D shells to reduce the burden on compupower. In this case, a shell FE analysis will be carried out.

Tis will be another FE analysis that Esha is asked to do. Esha has to replicate the same 1D Pipe Guide resby using Plate / Shell elements in Salome Meca. Esha will have some problems o understanding where toinormation or the analysis, but with careul guidance given by John, she will be able to successully perormanalysis and demonstrate results to John. You will learn how to visualise maximum and minimum stresses shell.

Case 7: Basic 3D Finite Element Analysis

Tis case re-introduces the world o 3D analysis, where a amiliar Pipe Guide Analysis that was carried previously by 1D and shell elements will be carried out with a 3D model.

Here, additional concepts o How to apply Force on a Surace is described. Also described is the differebetween 1D, Shell and 3D analysis results. When Esha gets results in her 3D analysis that are inconsistent w


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Stud

xix

previously carried out 1D and shell analysis, John explains her the difference in results. You will learn wh-refinement is and also get a hands on experience o the time it takes to compute when the number o elemare increased.

Case 8: 3D Finite Element Analysis with Hexahedral Linear Mesh

Tis is the study which shows how to conduct FE Analysis with Hexahedral Linear meshelements. John asks Eto conduct the analysis that they did or Axisymmetric Pressure Vessel with 3D hexahedral elements.

You will learn how to add Sub-Mesh to an existing 3D hexahedral mesh.

Case 9: 3D Finite Element Analysis with Hexahedral Quadratic Mesh

Afer the first exposure to 3D analysis and hexahedral elements, John thought that it is time to take this up a noand refine the mesh elements to Quadratic elements.

In this analysis a Pressure Vessel and Nozzle junction is analysed with Hexahedral mesh elements that are Quadr

in nature. A orce o 10kN will be applied on the ace o the nozzle and the stresses and deflection will be obtairom the analysis.

You will learn how to partition a geometry to make it suitable or hexahedral meshing. You will also learn hoperorm Boolean operations on the Geometry and how to translate and rotate geometries. Some o the advantypes o Boundary Conditions will be discussed in this chapter.

Case 10: Finite Element Analysis o a Pseudo Assembly

Once you get a taste o 3D FE Analysis, and you get a very good eel o how to do it efficiently in Salome-Meca Code_Aster, the next step is to see stresses in individual partso the Model.

In this case, John describes a way to conduct 3D FE Analysis or Pipe Guide Weld Assembly which has only 1 mbut the user can visualise stresses or individual Assembly Parts.

Case 11: Finite Element Analysis o a 3D Assembly

Tis case will show one o the true capability o Salome Meca where a previously conducted 3D FE analysis wire Analysed by separating individual parts and then conducting the analysis as an Assembly.

Tis analysis will be ocused on stresses in individual parts and how they interact with each other at their Consuraces. How to create a Geometry and mesh it to make it ready or Assembly analysis. How to generate

command (.comm) file or an Assembly analysis. You will also learn how to use ASK, a GUI or Aster or analysis.

Afer describing all the types o analysis that John and Esha are going to have a look at, John showed Esha desk where she will be working as an intern. Tis computer was not a hi-fi top o the notch computer but a 3 y


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Getting to know Salo

1

Chapter 1Getting to know Salome-MecaBeore starting straight on FE Analysis, John explained thata bit o homework beore hand will make sure that the studygoes smooth. It is always good to accumulate all the requiredinormation viz. What are the geometric inputs, what materialproperties will be used and what are the Specific results required offthis analysis.

Even though John was showing Esha how to operate Salome-Meca, he

explained the input values, geometry and the specific results they wereafer as i they had got that inormation rom the client. Esha was writingdown the inormation that she got rom John verbally.


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3

Step 3: Model Geometry

Booting the computer was ast and Ubuntu 12.04 was ready or inputs.

Following steps are to be taken afer you have started you Ubuntu OS.

# Description Figure

1 When Ubuntu starts, it looks like figure below

2

3

As can be seen when Salome-Meca is installed, you get an icon on the Desktop.

Tere are two ways to start Salome-Meca.

One is to open terminal and go to the older where Salome-Meca is installed and then type

./runAppli

Other is to Double Click Salome-Meca icon to start it.

Afer Salome-Meca Application Loads it will look like figure below.


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4


4

5

Te toolbar o Salome-Meca looks like figure below.

Te first line has common Menus like File, Edit, View, ools, Window and Help.

Te second line has tools like New, Open, Save, Close, Copy and Paste

Next to Paste button is the drop down or SALOME Module Selection. Different modules availableSalome-Meca are Geometry, Mesh, Post-Pro, YACS, JobManager, Aster, Eficas, OpenURNS, Homaand ParaVis.

All o the Modules are also shown as buttons next to the drop down

6

7

Click Down Arrow where it saysSalome-Meca and Select Geometry.

A window pops up like the adjacent

figure. Inormation on the window aresel-explanatory.

Click New


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5


8

In Salome-Meca main toolbar, Click

New Entity -> Primitives -> Box

In the Box Construction window, selectSecond Algorithm (Option Button)

Keep Deault Name Box_1

In the Dimensions at origin, fill invalues as shown in the figure on theright

Click Apply and Close

9

Hover over the toolbar (shown below) and when you pause or a second over a button, it will display tname o the button.

Select 5thButton rom the lef in the tool bar (Fit All) and the Entire box will fit to screen.

10

Tats it, you have created the geometryand are viewing it properly and thismodel will be used or Analysis.

Note that Salome-Meca also created 4additional items. A point on the Origin,Vectors in X, Y and Z direction.1

Now we need to define Geometric

groups that will be helpul in FEAnalysis.


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6


11

Make sure that Box_1 is selected in theObject Browser

In Salome-Meca main toolbar, ClickNew Entity -> Group -> Create

In the window that pops up, select thirdOption or Shape ype or selectingFaces on the Geometry.

Enter Fixed as Name.

Rotate the model so that you can seethe bottom ace.2

Click the mouse button again to deselectit so that you can select the ace.3

Click on the Bottom ace and it will behighlighted with White edges.

Click Add button in the Create Groupwindow and the ace number will beadded as shown.

Click Apply.

Repeat the steps or selecting the topace and name it Press. Add it and

then instead o clicking Apply clickon Apply and Close

12

Your Object Browser on the lef shouldlook like the adjacent figure.

Right click on Box_1 and select Showonly OR click on the Eye icon on thelef o Box_1 to highlight it and thenun-highlight eye icons or Fixed and

Press and it will do the same thing.


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7


13Save your file at a proper destinationand give it a meaningul name. HereJohn gave it a name Case1.hd

As John saved the file, Esha was intrigued by the ease with which simple geometries can be done in Salome-MJohn explained that the next step is to Mesh this Geometry.


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8

Step 4: Meshing Geometry

Step by Step example o how to mesh the geometry are shown below.

Following steps assumes that you have completed Geometry Creation steps as per previous Section and have sathe file to a meaningul location with a meaningul name.


1

In Salome-Meca main toolbar, Click thedown arrow where it says Geometry andSelect Mesh.

Make sure that Box_1 is still selected inthe Object Browser and click Mesh ->Create mesh and a window will pop upas shown here.

Keep deault name o the mesh as

Mesh_1.

Make sure Box_1 is in the Geometryfield. (I not, select the curved arrownext to Geometry and select Box_1)

In the 3D, Algorithm drop down selectNetgen 1D-2D-3D


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9


2

For the Hypothesis (which is grey atthis stage and shows ) Click onthe Gear Button and select Netgen 3Dparameters.

In the Hypothesis Construction windowthat pops up, keep deault parameters

and click OK

3

Now you will be back to the Create meshwindow.

Click Apply and Close button


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10


4

Nothing happens to the 3D model. Sowhere is the mesh?

I you check Object Browser you will seethree new entities added to the Mesh

ree.

Hypotheses, Algorithms and Mesh_1.

Mesh_1 has an exclamation mark onit which suggests that it needs to becomputed.

5

Right click Mesh_1 in the ObjectBrowser and select Compute.

Afer some time, i everything goes wella Mesh computation succeed Windowwill pop up which will give inormationabout the mesh that was created.

It shows total number o Nodes, Edges,Faces and Volumes. It also showswhether the Mesh is Linear or Quadratic(more on this later)


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11


6Close Mesh Inormation window andyou will be able to see the mesh that wascreated or your Analysis

It is this easy said John and then clicked on Save Button beore going any urther. Ten John went on and that In the next section, we will discuss how to build inormation or a Linear Static FE analysis by using SalomMeca Wizard.


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12

Step 5, 6, 7, 8 and 9: Salome-Meca Linear Static Analysis Wizard

John said that we have completed Steps 1, 2, 3 and 4 or conducting a FE Analysis. We made our Geometric mand gave it Geometric Groups and then we created a 3D mesh o the Geometric model which will be used orAnalysis. John re-iterated the steps as he knew that more Esha repeats the steps the more confident she will g


1

In Salome-Meca main toolbar, Clickthe down arrow where it says Mesh andSelect Aster.

Make sure that Mesh_1 is still selectedin the Object Browser and in Salome-Meca main toolbar Click Aster ->Wizards -> Linear Elastic, and a windowwill popup.

Te first step is to define the type oModel. Tis is Step 5 in FE Analysisfigure.

Select 3D, rom the drop down, i notalready selected and click Next.

2

Te next step is to select the Mesh that

will be used or the Analysis. Tis isStep 6 in FE Analysis figure.

I Mesh_1 is not already selected here,Click the Curved Arrow and selectMesh_1 in the Object Browser and itwill be added to the Analysis.

Use geometrical groups should beautomatically selected, and i not, selectthis option and click Next


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13


3

Next define the Material Properties tobe used in the analysis. Tis is Step 7

in the FE Analysis figure.

Add Youngs Modulus and PoissonsRatio.

As we have our dimensions inMillimeters, our Youngs Modulusshould be in MPa.

Input the values as shown in the adjacentfigure and click Next.

4

Next we input Geometric BoundaryConditions. Tis is Step 8 in the FEAnalysis figure.

Tis is where the Geometric Groupsthat were defined at Geometry creationstage comes in handy.

I Fixed is not already selected bydeault, double click below Group andselect Fixed rom the options.

I DX, DY and DZ values are not already0 (zero) enter it manually and clickNext


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15


7

Afer saving the file, you will be takenback to the Wizard where the filelocation will be displayed.

Ten you need to Click Finish.

8

A new branch Aster will be created inthe Object Browser.

Open Aster branch and you will seelinear-static underneath it.

Tis concludes the Pre-Processing stage o FE Analysis said John while he clicked on the Save button. He adSalome-Meca wizards make it very easy to conduct a basic analysis. Esha noted that it only took them 10 minto reach to this stage and most o Johns time was taken up to explain her how to use the Wizard. I John had tthis analysis by himsel, he would have reached this stage in no time. John said, Next, we will discuss how toa Linear Static FE analysis by using Salome-Mecas Aster module.


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16

Step 10: Run the analysis

I you have created your geometry, meshed it properly and have created the Command file that tells the Procewhat is the type o analysis, what the boundary conditions are and what results we are afer, the next step becoeasy said John. But we havent mentioned anywhere what results we are afer said Esha, quickly pointing ouJohn that he might have missed a step somewhere. John smiled and he was happy that Esha was paying attent

He said, Salome-Meca makes it easy or the first time users and depending on the Analysis ype the user selit selects what results will be generated. He went on and said that Tis output type can be changed based onresults we are afer by editing the command (.comm) file, but or this analysis we will use the deaults


1Right Click the linear-static branch in

Object Browser and Select Run.


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2

A new window will pop up and therewill be numbers flying around thescreen.

Right now the inormation that waspassed on to the Processor or Analysisis being calculated.

I everything goes right, a new BranchPost-Pro will be added to ObjectBrowser.

3

John said that I you can NO seePost-Pro branch in the Object Browser,it means that there is something wrongwith the analysis.

I an error occurs at this stage, it wouldbe better i the user Re-iterate all thesteps careully and conduct the analysisagain.

John clicked on the save button and said, As we can see that a Post-Pro node has been added to the Object Browtree, Processing has completed and that results are ready or us to be evaluated. Depending on the ypAnalysis, it can take a ew minutes as it happened now or it can take several hours said John. Next we willsome o the ways we can visualize the results in Post Processing Module o Salome-Meca.


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Step 11: Post Processing o the Results

We will find out the results o our FE Analysis in this step said John.


1

In Salome-Meca main toolbar,Click the down arrow where itsays Aster and Select Post-Pro.

Open the Post-Pro branch tillyou see three branches in theparent branch o Fields.

Fields is the branch that holds

the results o the analysis.


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2

RESU____DEPL means, Result(RESU) o the Displacements(DEPL) o the nodes.

Open this branch and RightClick on 0 , -. From the popup window select DeormedShape

Check Magnitude coloring andkeep the deault Scale Factor


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5

A new sub-branch De.Shapeis created in RESU____DEPL-> 0 , - branch.

Te deormed Shape is shown asWire rame model.

6Notice that at the bottom o the window, a graph o Deflection with minimum and maximumdeflections is shown.

Te maximum deflection here is 0.004734mm

7

Right Click on De.Shapeand select Show Only andon the right hand side only theDeormed shape will be visible.

Right Click on De.Shape andselect Representation -> Suracerame, and you will be able tosee the deormed 3D model.

As can be seen maximumdeflection is at the top o thecube (as expected) and zerodisplacement is at the bottom othe cube (again as expected)


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8

Now, in this step, Right Click on0 , -. From the pop up windowselect Deormed Shape

Check Magnitude coloring andkeep the deault Scale Factor

Click Scalar Bar ab and thenin the Scalar range: section,

Click the down arrow on ScalarMode and Select [1] DX, -.Keep everything else deault andClick Apply and Close

As can be seen two or moredifferent type o visualisationcan be added to the study irequired.


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9

Right Click on De.Shape:1and select Show Only andonly the Deormed shape will be

visible.

Again, Right Click onDe.Shape:1 and selectRepresentation -> Surace rameand you will be able to see thedeormed 3D model.

Here you will be able to see howthe cube deorms in X directiononly.

I you zoom in and rotate themodel you will be able to seebulging occurring in the Xdirection.

10

You can view deflections in Y and Z direction by ollowing step 8 and 9 above and Selecting DYor DZ.

Play around with the Scale Factor in the Deormed Shape ab and see the deormation change.


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11

RESU____SIEQ_NOEU is theResult (RESU) o the Stress(SI__) Equivalent (__EQ) orEquivalent Stresses at Nodes(NOEU).

Open this branch and Right

Click on 0 , -. From the popup window select Scalar Map

Select [1] VMIS (VonMisesStress) rom the Scalar Modeand keep the rest as deault

Click Ok


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15

In a similar ashion o showingmultiple branches o Deflection,

multiple branches o Stressescan be shown. A Scalar Map oresca Stresses can be added tothe study as well.

Right Click on 0 , - sub-branch.From the pop up window selectScalar Map

In Scalar Bar ab in the Scalarrange: section, Click the downarrow on Scalar Mode andSelect [2] RESCA, -. Keepeverything else deault andClick Apply and Close

Right Click on Scalar Map andselect Show Only

Right Click on Scalar Map andselect Representation -> Suracerame


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16

RESU____SIGM_NOEU isthe Result (RESU) o the Stress(SIGM) or SIGMa at Nodes(NOEU). Six stresses Sx, Sy, Sz,Sxy, Sxz, Syz

Open this branch and RightClick on 0 , - sub-branch.From the pop up window selectScalar Map

Select [1] SXX (Stress in Xdirection) rom the Scalar Modeand keep the rest as deault andClick Ok

Right Click on Scalar Map andselect Show Only

Right Click on Scalar Map andselect Representation -> Suracerame.

Now lets see how we can run a second analysis in the same .hd file by adding a new FE Analysis in Aster Mod


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1

Click the down arrow whereit says Post_Pro and SelectAster.

Make sure that Mesh_1 is

selected in the Object Browserand click Aster -> Wizards ->Linear Elastic and a window willpopup.

Select 3D i not already selectedand click Next.

Click the Curved Arrow andselect Mesh_1 in the ObjectBrowser (i not already selected).

Use geometrical groups shouldbe automatically selected, inot select this option and clickNext

Use the same GeometricBoundary Condition as perprevious analysis. For LoadBoundary condition, insteado Press value to be 1 doubleclick it and input a value o 10.

Click Next.

2

Save this command (.comm)file as Pressure10.comm todifferentiate it rom the previousanalysis carried out.

Click Save

Click Finish


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3A new analysis will be added toAster linear-static0

4

Right Click linear-static0 andSelect Run.

I everything goes well a newbranch will be created in thePost-Pro module called linear-static0.rmed

5 o find out the Deflection and Stresses or this analysis, repeat steps 2 to 16 shown previously.

Well thats the complete FE Analysis o a Carbon Steel Cube. Te analysis I just showed you is very helpuunderstand the steps required in Finite Element Analysis. It might not have any practical use though, said Jo

John saved the entire Analysis and closed Salome-Meca. Now I understand the undamental steps o howperorm FE Analysis in Salome-Meca but there are quite a ew questions that come to my mind said Esha. Jwas happy to see that Esha had questions to ask as he now knew that she was paying attention.

What i I want to carry out Sel Weight analysis, or apply Force instead o Pressure? How do we do that in SaloMeca? asked Esha. Tat is what I am going to show you next but beore I do that lets recap o what we did rnow said John.


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31

Summary

Esha listed out the steps that they ollowed to perorm the analysis out loud

1. We Started Salome-Meca and entered Geometry Module and created a New Study.

2. We created a Primitive Cube and named the top and bottom ace which we used in FE Analysis.

3. We meshed the model with tetrahedral mesh elements in Mesh Module.

4. Ten we entered Aster Module and created a new Analysis by using Linear Static Analysis Wizard.

5. We entered required inormation, saved the command (.comm) file and completed the Wizard.

6. We Ran the analysis and as everything went well, we were presented with Post-Pro Module Option.

7. We entered Post-Pro Module and saw Deflected Shape o the Model, VonMises Stresses and resca Stre

8. We built another analysis in the same study file and completed analysis by visualising results in Post

module

Very good said John, but dont orget that even beore you start the analysis make sure you have all the inputoutput parameters or your study that has been discussed with the client.


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PS Using Efficient to generate command (.comm) file

How to generate this same command (.comm) file using Efficient


1In Mesh ab, keep everythingdeault


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2In Analysis ab, keepeverything deault

3

In Material ab, Enter theinormation as shown in theadjacent figure.

Click Add to add this materialto the command file.

4 We dont need to enter anything or Element ab


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5

In Boundary Condition(s)ab, Enter the inormationor restricting ace Fixed inAll directions as shown in thefigure.

Click on Add

6

Next we need to add Loads inthe Load(s) tab.

First we will add Pressure o 1MPa. Change the Load ype toPressure.

Enter Press or Load Nameand Press or Is Assigned to.For the Amount o Pressureenter 1.

Click Add

For this study we do not needto step the load cases.


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7

Next Click on Output ab.

Here we will click Add ALLbutton to add all optionsavailable or this analysis.

8

Click Save .comm file.

Save it in the location whereyou saved the study.

Remember to add ull name(with .comm) in the File name.


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Chapternotes

1 In CaeLinux 2011 these entities were not generated by deault but in Salome-Meca 2013.2 they are.

2 Click Second button on the figure shown in Step 11 (looks like a mouse) which will help you to zoom, pan and rotathe geometry. Alternatively you can perorm these operation by Holding down Ctrl key and using Lef, Middle orRight mouse buttons respectively.

3 I the mouse button is still selected, you wont be able to select the ace. I you are using Ctrl key with mouse buttoyou dont have to click this mouse button again.


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Notes:


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Editing command (.co

39

Chapter 2Editing command (.comm) file

John explained that the analysis he was going toshow next was a very simple analysis and ollowsthe same steps that he had presented previously. Inthis analysis they will manually edit the command(.comm) file, remove the pressure load and applyGravity load to the entire 3D model.


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Step 1: Purpose o the FE Analysis / Description o the problem

John told Esha that this analysis is or understanding how to edit a command (.comm) file manually. He will sEsha how gravity load is applied to a cantilever beam. Te main aim o the study was to see the effect o sel-weon a 1m Long and 10mm square Carbon Steel cantilevered rod. Only sel-weight o the rod was considered instudy. John said that here we will not go into details o matching the results o FE Analysis with hand calculat

based on theory.

Step 2: Input values or the FE analysis

Dimensions o the rod are as ollows

Width and Length o Rod: 10mm x 10mm

Length o Rod: 1000mm (1m)

Youngs Modulus: 2.1e5 MPa

Poissons Ratio: 0.3

Density o Carbon Steel: 7.8e-9 tonne/cubic mm (7800 kg/cubic meter)

Gravitational Acceleration: 9800 mm/square second (9.8 m/square second)


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John started Salome-Meca and created a new Study. He then enabled Geometry Module and started the inpuRod 3D model.


1

For generating the Square Rod3D model, we need to create abox.

Click New Entity -> Primitives-> Box and enter the values asshown in the figure and leaveits Name as Box_1. Click onApply and Close


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2

Now we need to create a Facegroup o the ace which will beused in FE Analysis to fix theGeometry.

Rotate the model so that theace on the YZ plane is visible.

Click New Entity -> Group ->Create.

Select Tird Option ButtonFace.

Change the Name to Fix

Now select the Face o thesquare rod that is on the YZplane.

Once the correct Face isselected Click Add and thenClick Apply and Close as wedo not need to create any moreGroups or this study

Save the file with a meaningul name. Next we will Mesh it, said John.


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John said that in this study we will mesh the Model with the deault Mesh size given by Salome-Meca.


1

Select Mesh Module in Salome-Meca.

Click on Box_1 in the ObjectBrowser and then Click Mesh-> Create Mesh.

In the Window, make sure

Box_1 is selected as Geometry.

Select Netgen 1D-2D-3D asthe Algorithm and or theHypothesis Click on the GearButton and Click Netgen 3DParameters.

In the window that pops up,leave the Deault settings andClick Ok.


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2

Your Create Mesh windowshould look like the adjacentfigure.


3

A new Mesh_1 will be createdin the Object Browser.

Right Click Mesh_1 and selectCompute.

I Everything goes well youwill be presented with theinormation o the mesh that iscreated.

Click Close on this window.

John clicked on the Save button and asked Esha Are you ready or the next Step?

You bet I am was the answer John got.


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Step 5, 6, 7, 8 and 9: Salome-Meca Linear Static Analysis Wizard

John said Esha, do you know what we do next?

Esha said that the next step is to use Salome-Meca Linear Static Wizard to create a command (.comm) file whwill hold inormation about the analysis that we are going to do. Ten Esha paused and said, But as Salome-MLinear Static Wizard does not have Gravity load case, you are going to show me how to edit the command (.comfile by hand.

You know the steps urther, so I am going to hurry and do it mysel and explain them in short, said John.


1

Click on Aster Module and Make sure that Mesh_1 is still selected in the Object Browser. In Salome-Memain toolbar, Click Aster -> Wizards -> Linear Elastic, and a window will popup.

Select 3D as type o analysis. Click Next

Select Mesh_1 in the next step i not already selected. Click Next

Enter 2.1e5 or Youngs Modulus and 0.3 or Poissons Ratio. Click Next

For Geometric Boundary Condition select Fix and give it values 0, 0, 0

2

For Load Boundary Condition

as we dont have any other aceto apply, select Fix and leavedeault o 1 or Pressure. ClickNext


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3Save the File by giving it a nameGravity and Click Finish

Tis completes the steps to generate a study and save the command (.comm) file as we did earlier or the cusaid John. Now we want to edit the command (.comm) file, remove Pressure term and add Gravity load to it.


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Step 8 and 9 again: Manual editing o command (.comm) file


1

Open the older location whereyou saved the Gravity.commfile recently by just doubleclicking it.

I your Ubuntu installationis unchanged, this file shouldopen in gedit.


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2

When the file opens, it shouldlook like the figure shown here.

Dont worry i you do not

understand what all those linesafer lines o code are and howthey interact with Salome orCode-Aster.

At this stage what we need todo is very simple


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3

Find the words MA=DEFI_MAERIAU which definesthe Material that will be usedor the Analysis. Tese are

generally specified at thebeginning o the file.

At the end o the sentence thatis highlighted in the adjacentfigure we want to add Density oSteel to the Material definitionas it is not added by deault.

Density o material is requiredi we want to apply Gravity load

on it.1

4Add RHO=7.8E-9, ashighlighted in the adjacentfigure. Density units are intonne / cubic millimetre.2


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5

Find the words PRES_REPwhich is the pressure term thatwe entered on ace Fix with a

value o 1.

Select the entire sentence thatis highlighted and delete it bypressing Delete.

6Replace the above sentencewith the one shown here


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7

So what did we do here? PESANEUR literally means GRAVIY in French. ranslate it and see yoursel.

So we are writing a code that says that we want to add Gravity Load to the study. Te amount o load toapplied is 9800 mm/square second,3and that it should have a direction o Negative Z (-Z) which is sho

by a vector (0,0,-1) => (X=0, Y=0, Z=-1).4

John saved the file Gravity.comm and said that the next step is to run this analysis.


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Step 10: Running the analysis


1

Open Salome-Meca again and check that Case2.hd file is Open. Make sure that Aster module

selected.

Right Click the linear-static branch in Object Browser and click on Run.

A new window will pop up and as you know numbers will be flying around the screen.

I everything goes well you will be able to see Post-Pro appear in Object Browser.

Te next step is to visualise the results.


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2Ten she opened RESU____SIEQ_NOEU branch and added Scalar Map with the Mode as VMIS

For this VonMises stresses, she enabled Show Only and changed the Representation to Surace

John said that at this stage dont worry i the results o the analysis are not what you would get rom the Ma

Calculations. Te sole purpose o this Analysis was to show you how to manually edit the command (.command add Gravity load.

Afer Esha stopped fiddling with the Post Processing Module, she told John that when he started showing her hto do FE Analysis with Wizards in Salome-Meca, she was not sure i it could be flexible and powerul but afersecond example she has more confidence in what she is learning and hopes that all o her queries will be solve

John told Esha that they have barely scratched the surace o what lies ahead o them. Salome-Meca is powerul tool i the user knows how to use it.


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Summary

Esha summarised her learning

1. How to manually edit the command (.comm) file to change deault Linear Static Wizard inormation

2. How to add Gravity load

John said that now it was time or a coffee break as they were doing this or more than an hour.


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PS Using Efficient to generate command (.comm) file

How to generate this same command (.comm) file using Efficient


1

In Mesh ab, keep everythingdeault as we are starting a NewAnalysis, we are using MEDfile and we are conducting

Linear Static Analysis


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2

In Analysis ab, keepeverything deault as we areperorming Mechanical 3DAnalysis.

3

In Material ab, Enter theinormation as shown in theadjacent figure or CarbonSteel material.


4 We dont need to enter anything or Element ab


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5

In Boundary Condition(s)ab, Enter the inormationor restricting ace Fix inAll directions as shown in thefigure.

Click on Add

6

Next we need to add GravityLoad in the Load(s) tab.

Change the Load ype toGravity.

Enter Gravy or Load Nameand All or Is Assigned to. oadd gravity enter -9800 inFZ.

Click Add

For this study we do not needto step the load cases


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7


Here we will click Add ALLbutton to add all optionsavailable or this analysis.

8





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Chapter notes

1 Or any other type o load that requires density o the material, like doing FE analysis o a rotational body.

2 Tis units are consistent with mm, N, MPa, mm/s^2

3 Remember our units are mm, second, tonne, Newton, Mega Pascals etc.

4 Same results can be achieved by the value o -9800 and vector o (0,0,1)


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1D Finite Element A

61

Chapter 31D Finite Element Analysis

Afer both John and Esha had a casual chat over coffee,when they returned to the computer John said, Now thatI have showed you what Salome-Meca looks like, next Iwill show you how to perorm 1D Analysis. For this FEAnalysis John will show 1D Geometry Modelling in Salome-Meca. Ten they will generate a command (.comm) file by

using Eficas, then use ASER module o Salome-Meca to carryout the analysis and do Post Processing in Salome-Meca.


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Step 1: Purpose o the FE Analysis / Description o the problem

John showed Esha some o the Manual calculations that he had perormed to find the maximum deflection stress generated in a Pipe Guide based on bending theory o cantilever beam.

He explained Esha that we will reproduce this manual calculation result by FE Analysis. In this instance a sim1 Dimensional linear staticFE analysis with Beam elementswill be perormed.


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Open Salome-Meca, start a new Study and Enable Geometry Module.


1

Click New Entity -> Basic -> Point.

A new window opens asking or Co-ordinates o the Point.

Select first Algorithm in Points.

Enter P1 as Name.

Enter 150, 0, 0 or X, Y and Z.


2

Now we need to create a Line with thetwo points.

Click New Entity -> Basic -> Line.

Select first Algorithm or Line by twoPoints.

Click on the Curved arrow on the righto Point 1 and Select Point O romthe Object Browser.

Repeat above step or Point P1

Click Apply and Close.


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1D Finite Element A

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3

Next we need to give Names to thegroups o Entities so it becomes easy toconduct FE Analysis.

Click on New Entity -> Group ->Create.

In the window that pops up select firstAlgorithm or selecting Points. Give ita name Fix and rom the 3D windowselect the end o Line_1 which is onthe Origin and Click Add. When this

point is added to the Selection (Entitynumber 2 in this case), click Apply.

Do the same or the other end o theline and give it a name Load.


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4

Next we need to create a group o Line.

On the top o Create Group window,select second Algorithm or Lines.

Enter Guide or Name.

Select the only Line rom the 3D modeland click Add.


5Your Object Browser should look likeadjacent figure.

6 Save this file and give it a proper name. I have used Case3.hd


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1D Finite Element A

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John enabled Mesh Module in Salome-Meca and started the procedure to generate the Mesh.


1

Click Mesh -> Create Mesh and in thewindow that pops up, keep deaultname Mesh_1, make sure thatLine_1 is selected as Geometry.

For 1D algorithm select WireDiscretisation rom the drop downbox.

Click on the Gear button next toHypothesis.

2

In the pop-up window select Nb.Segments and the window shown inadjacent figure will pop up.

Keep deault Name and Enter 10 orNumber o Segments.

Click OK on this window.

Click Apply and Close on CreateMesh window.


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3

Right Click Mesh_1 in the ObjectBrowser and Click Compute.

I everything goes well, you should beable to see that there are 11 Nodes and10 Edges in the Mesh.

4

Right Click Mesh_1 in the ObjectBrowser and Click Create Groupsrom Geometry.

Select three Groups that we createdin Geometry module and they willbe added to the window as shown inadjacent figure.

Click Apply and Close.


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1D Finite Element A

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5Your Object Browser should look likeadjacent figure

6 Save this file.

Tis concludes creation o the Mesh or the FE Analysis, said John. Next we will create a command (.comm)that will give instructions to Aster about the Analysis.


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Step 5, 6, 7, 8 and 9: Creating command (.comm) file with Eficas

Tere are several ways in which we can generate command (.comm) file, said John. One is to create it withhelp o any ext Editor, second is to use Salome-Meca Wizard and the one we will be looking at is using EficEficas is an application that generates syntactically correct command (.comm) files. Tis does not mean that will make sense and that there will be no errors while running the Analysis. Tis only means that there wi

little to No chance o missing a comma or a Closing bracket, still the inormation to put in the file has to corom the user.

For this analysis I will show you the use o Eficas and then you can decide i you want to use it or uture anaor create the command (.comm) file manually, said John.


1

In Salome-Meca select Eficas module to enable it.

Eficas has not been ported to English yet so everything you will be doing rom now on will have Fren

language, including ool ips.

2

In the Main ool Bar, Click on Eficas-> Eficas pour Code Aster.

A new application Eficas starts.

As said earlier, it is not in English butthe icons can be understood.

From lef to right, icons are

1. Create a new file

2. Open a file

3. Save a file

4. Copy

5. Paste

6. Delete

7. Cut

Click on Create a new file icon


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5

Afer the file is saved, the Eficas window looks like that shown below. In the lef column it shows file name Case3.comm in Red colour. Tis means that this file is not complete. When the file willcomplete, i.e. when it will have all parameters defined like Start, End, Material definition, Mesh definitiLoad and Boundary condition defined, it will become Green. At this stage Eficas is ready or Input rthe user.

Te second Column shows all the commands that are available in Code-Aster and these are sorAlphabetically. Tey can be sorted based on groups but in this instance we will stick to Alphabetic sorti

Inormation that needs to be entered in command (.comm) file are called Concepts in Code_Aster and need to add ollowing Concepts

1. DEBU (Tis is the marker or file start)2

2. Material Definition

3. What type o Mesh file to read3

4. ype o Modelling (1D, 2D, 3D, Mechanical, Termal etc)

5. Assign previously defined Material to the Model

6. Add Geometric Boundary Conditions

7. Add Load Boundary Conditions

8. Define type o Analysis (Static, Linear, Non-Linear, Dynamic etc)

9. Results to be calculated at the Elements and Nodes

10. Save the results to a MED file4

11. FIN (Tis is the marker or file End)


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1D Finite Element A

73


6

In the second Column scroll down to DEBU, Click it and then Click on Valider5Button at the botto

When you do that, DEBU gets added to the comm file and it has Green button which means that no ex

inormation is required to be entered.

wo abs Ajouter Mot-Cle (Add Keyword) and Nouvelle Commande (New Command) are shown

7

Next we need to define Material to beused in the study.

o add a new Command Click onNouvelle Commande and SelectDEFI_MAERIAU which meansDEFINE MAERIAL, Click Valider.

DEFI_MAERIAU gets added to

comm file with Yellow, which meansthat you need to add more inormationto it as it is incomplete.

Te middle section has a new abNommer Concept which is to addthe name o the Concept.


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8

Find ELAS (Elastic) rom MotsCles Permis (Permitted Keywords)and Double Click it to add to the

command (.comm) file.

wo other branches need to be filledto make ELAS keyword Green, theyare Youngs Modulus (E) and PoissonsRatio (NU).6

9

Click on E and add value 2.1e5 andClick Valider.

Click NU and enter 0.3 and ClickValider

Now, ELAS should turn Green butDEFI_MAERIAU is still Yellow. Tereason is that we need to save thisConcept with a Name.

10

Click on DEFI_MAERIAU, thenClick on Nommer Concept and enterCS as the name o the Concept.7

Click Valider to add it to file, andthen DEFI_MAERIAU should turnGreen.


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1D Finite Element A

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11

Next we need to define the type oMesh file that will be read as input.

Click on Nouvelle Commande ab

and find LIRE_MAILLAGE, DoubleClick it to add to the file.

Ten Double Click FORMA andthen Double Click MED.

Click on LIRE_MAILLAGE againand give it a Name mesh.

12

As we will need to apply BoundaryConditions on the Nodes, it isimportant that the MED file has

inormation or the node group.

o do this, we will need to definenode group rom the element groupsand that means we need to add DEFIGROUP to the file.

Click on Nouvelle Commande aband find DEFI GROUP and DoubleClick it to add to file.

Click on MAILLAGE and select

mesh that was defined previously


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13

Next, we need to make a Group o theentire Mesh and call it OU.8

Click on DEFI_GROUP and DoubleClick CREA_GROUP_MA romSecond Column.

Click on NOM and give it a nameOU and Click Valider.

Double Click on OU and thenSelect OUI, which means give nameOU to All Mesh elements.

14

Next we need to convert this group oMesh to group o Nodes.9

Click on DEFI_GROUP and DoubleClick CREA_GROUP_NO rom

Second Column.Click on b_option and SelectOU_GROUP_MA and ClickOUI which means convert All MeshGroups to Node Groups.

Click on DEFI_GROUP and selectmesh rom Nommer Concept


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1D Finite Element A

77


15

Ten we need to define the type oModelling.

Click on Nouvelle Commande aband find AFFE_MODELE (AssignModel), Double Click it to add to thefile.

Double Click MAILLAGE and thenDouble Click mesh

Double Click AFFE, Double ClickOU and then Double Click OUIwhich means that the modelling is orthe entire Mesh.10

Click on PHENOMENE and DoubleClick MECHANIQUE.

Click on b_mechanique and DoubleClick MODELISAION and thenAdd POU_D_ to the file.11

Give a name o model to AFFE_MODELE

16

Next we Add Material Propertiesdefined previously to the Model.

Click on Nouvelle Commande aband find AFFE_MAERIAU (AssignMaterial), Double Click it to add to thefile.

Next add MAILLAGE = mesh,

For AFFE add

OU = OUI and

MAER = CS.

Give it a name material


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17

Now we need to define the Geometryo the Beam that we are going toanalyse.12

Add a new Concept AFFE_CARA_ELEM and give it inormation asshown in adjacent figure.

Here we are defining it as a RectangleCross Section with Width (HY) = 100and Tickness (HZ) = 10.

Give it a Name Guide

18

Next add Geometric BoundaryCondition.

Add a new Concept AFFE_CHAR_MECA and give it inormation asshown in adjacent figure.

We are fixing this point by addingvalue o 0 to all degrees o Freedom.13

Give it a name Fixed


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1D Finite Element A

79


19

Next we add Load BoundaryCondition.

Add a new Concept AFFE_CHAR_MECA and give it inormation asshown in adjacent figure.

We are adding a Force in Z directionwith the value o 2000. As per ourunits, this is 2000N.

Give it a name ForceZ


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80


20

Next we define the type o Analysis andgive it all the required inormation.

Add MECA_SAIQUE (StaticMechanical Analysis) to the file andthen add inormation as shown inadjacent figure.

Note that we are adding two EXCIcommands to cater or two types oBoundary Conditions.

Give it a Name result

21

Next we define the types o resultsto be calculated rom the initialdisplacements calculated.

Add CALC_CHAMP to the file,and add the inormation as shown inadjacent figure.

Give it a name result, same asprevious.

Here we are trying to get two

inormation calculated,

SIPO_NOEU (Stress at Node) and

REAC_NODA (Reaction at Nodes)


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1D Finite Element A

81


22

Next we define the inormation to bewritten to MED file.

Add IMPR_RESU to the file and addthe inormation as shown in adjacentfigure.

Here we want DEPL (Deflection),REAC_NODA (Reaction at Nodes)

and SIPO_NOEU (Stress at Node).14

24

Last we Add FIN to show that this isthe end o the file.

Once you add FIN, Case3.commturns Green.

25 Save this file and get ready to Run the Analysis.


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1D Finite Element A

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3

I you have done everything correctly,Analysis should complete and youshould be able to see Post-Pro branchadded to the Object Browser

Save this study and next we will have a look at the Results, said John.


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84

Step 11: Post Processing o the Results

Now lets have a look at what does the FE Analysis tell about our 1D Analysis o the Guide.


1

First John enabled Deormed Shape or DEFI, showing the Deflection o the Free end o Guide.

Open Branch Result__DEPL._ and Right Click on 0, -. From the Pop up menu Select DeormShape. Leave everything deault and Click OK.

As can be seen rom the figure below, the Maximum deflection o the Right side edge is 1.29017 and bason our Units, it is 1.29017mm

2

Ten John enabled Stress in SIPO_NOEU. Tis has many results embedded in it, but the one we interested in is SMFY (Stress due to bending Moment MY).

As the beam is longitudinal to Global X axis, and so ortunately or us, Local and Global X, Y anddirection or this beam are the same16.

As can be seen rom the figure below, the Maximum stress generated at the Fixed point (lef side) is -1and based on our Units, it is -180MPa.


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1D Finite Element A

85


Result

Esha quickly made a able to show the difference between Hand Calculated values and that obtained by FE Analy

Result Hand Calc. Value FE Analysis Value Difference

Deflection 1.2857mm 1.29017mm 0.3%

Stress 180MPa 180MPa 0%

John explained that the difference in Deflection is mainly due to rounding error and also due to density o MI Esha wants, she can perorm the analysis again with increased Segments in the Mesh and compare results.

Summary

John asked Esha what she had learnt in this Case Study. Esha summarised her learnings

1. How to do 1D Geometry Modelling in Salome-Meca

2. How to create Groups o Nodes and Lines in Salome-Meca

3. How to Mesh 1D Geometry in Salome-Meca

4. How to create command (.comm) file in Efficas

5. How to run FE Analysis by using Aster without the Wizard

6. How to do Post Processing o 1D FE Analysis

John said, next we will take this 1D analysis to 2D Frame Analysis.


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1D Finite Element A

87


2In Analysis ab, Change theAnalysis ype to Mechanical Beam

3

In Material ab, Enter theinormation as shown in theadjacent figure.



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4

For the Element ab,

Select Beam or ype oElement.

Select Rectangle or Sectionype

Enter Guide or Is Assignedto

Enter 100 or Section Width(HY)

Enter 10 or Section Height(HZ)

Click Add

5

In Boundary Condition(s) ab,

Select D.O.F (DDL) on NodeGroup

Enter the inormation orrestricting ace Fix in Alldirections as shown in thefigure.

Click on Add


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1D Finite Element A

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6

Next we need to add Loads in

the Load(s) tab.We need to add Load o 2000Nin Z direction. Change theLoad ype to Force on Node.

Enter ForceZ as Load Nameand Load as Is Assigned to.

Enter 2000 or FZ.

Click Add

For this study we do not needto step the load cases.

7


Here we just want to addSIPO_NOEU and REAC_NODA so select them rom thetop list and click Add buttonto add them to this analysis.


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8





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What will be covered in V

a

What will be covered in Volume 2

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 Johns 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?

Editing and Generating Mesh in Salomes Mesh Module

Sometimes it is a requirement that Geometry need not be changed, as it might come rom a different sofware, some o the Meshes needs to be edited. In some instances, mesh aces needs to be extruded or nodes moved. Ewanted to know i there was a way to do it in Salome.

Combining element types in a single FE AnalysisEsha 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 Analysis

Esha said that what John taught her in Chapter 9 or checking against Allowable stress o the material was gobut she wanted to know i she could put the Graph o the Material Properties in Salome or Code-Aster and iAnalysis could take care o checking when the Allowable stress has been reached and stop the analysis?

Sliding Contact instead o Glued

Esha said that she was happy to perorm Assembly FE Analysis, but sometimes there is a requirement whereneeds sliding contact between suraces instead o glued. Was there a way to do it in Code_Aster?


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b

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 requenciethe object by perorming Modal Analysis?

Termal Analysis

Esha remembered that once she was asked i there was a way to perorm Termal analysis in Code_Aster.Esha didnt know, she had to again pass it along to her colleague. Is there a way to conduct Termal AnalysCode_Aster?

Tese were some o the example problems that she had the opportunity to do but was not able to due to her limknowledge. Tere were some more problems that she wanted to discuss with John but first she wanted to knoher existing problems can be solved.

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

Volume 2 Book Promotion - 35% Off

Volume 2 is comming out soon and to receive 35% discount on the list price, register your interest by writingemail to [email protected] with subject vol2-35p-off and you will be sent a Coupon to avail 35% offthe check out basket or Volume 2.


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App

c

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

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

5. Code_Aster orum http://www.code-aster.org/orum2/
http://www.salome-platform.org/http://www.code-aster.org/V2/spip.php?rubrique2http://engineering.moonish.biz/efficient/http://www.salome-platform.org/forumhttp://www.code-aster.org/forum2/http://www.code-aster.org/forum2/http://www.salome-platform.org/forumhttp://engineering.moonish.biz/efficient/http://www.code-aster.org/V2/spip.php?rubrique2http://www.salome-platform.org/


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d

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


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App

e


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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.

Now Open erminal and go to Downloads Folder
http://www.code-aster.org/V2/spip.php?article303http://www.code-aster.org/V2/spip.php?article303


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h

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.

Download Efficient version 0.1.0 rom http://engineering.moonish.biz/efficient/
https://apps.ubuntu.com/cat/applications/precise/openjdk-7-jre/http://engineering.moonish.biz/efficient/http://engineering.moonish.biz/efficient/https://apps.ubuntu.com/cat/applications/precise/openjdk-7-jre/


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Finite Element Analysis with

Open Source Sofware

Second Edition

By

Dharmit Takore

CPEng, RPEQ, Brisbane, QLD, Australia