Undergraduate Thesis 15 hp
WORK METHOD TO SIMPLIFY TRANSFER
OF 3D MODELS TO ANSYS FOR ANALYSIS
AT
ATLAS COPCO ROCK DRILLS AB
Frida Arnesson
Bachelor degree in Mechanical Engineering 180 hp
Örebro June 2011
Examiner: Johan Kjellander
Arbetsmetod för att förenkla överföring av 3D modeller till ANSYS för analys
Örebro universitet
Örebro University
Akademin för naturvetenskap och teknik
701 82 Örebro
School of Science and Technology
SE-701 82 Örebro, Sweden
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
1(29)
ABSTRACT
This is a 15 hp thesis in mechanical engineering performed at the CAX & PDM Solutions
group and the Applied Mechanics Group at the Rocktec division within Atlas Copco Rock
Drills AB, Örebro, during the spring 2011.
Today, the transfer of 3D CAD models created in Pro/ENGINEER (Pro/E) to ANSYS often
brings problems. The purpose of this thesis is to document the current work performed by the
Applied Mechanics Group when they import 3D CAD models created in Pro/E. It is also to
identify and define common problems. The objective for this thesis is to develop a work
method to facilitate the import of models created in Pro/E to ANSYS, thus saving time and
effort for the Applied Mechanics Group.
To achieve the objective a checklist was developed, to be used as a helpful guide during
projects that require analysis in ANSYS. The checklist also contains guidelines with tips for
Mechanical Designers that work in Pro/E. Through the checklist there are possibilities for
better communication and thereby better understanding between the Applied Mechanics
Group and the Mechanical Designers that work in Pro/E.
Each subject that is brought up in the checklist is a result of what the participants in
interviews, meetings and a questionnaire have talked about. The first appendix in the checklist
is a comparison of solutions in Pro/E and ANSYS and recommendations of where creation of
modifications is best performed. The other appendix is the guidelines for Mechanical
Designers with tips about modelling in Pro/E. An appendix to the guidelines was created with
more detailed information about some of the subjects.
The created work method can be a common ground to start from and a living document to be
updated. I recommend that all three documents are used in the project to get the most out of
the work method that have been created.
Frida Arnesson
June 2011
Örebro
Supervisor: Sören Hilmerby
Examiner: Johan Kjellander
Key words: CAX, CAD, Pro/ENGINEER, ANSYS
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
2(29)
Sammanfattning
Detta 15 hp examensarbete i maskinteknik har utförts på CAX & PDM Solutions gruppen och
Applied Mechanics gruppen, på Rocktec divisionen inom Atlas Copco Rock Drills AB,
Örebro, under vårterminen 2011.
I dagsläget medför ofta överföringen av 3D CAD modeller skapade i Pro/ENGINEER (Pro/E)
till ANSYS, problem. Syftet med detta examensarbete är att dokumentera arbetet i samband
med överföringen av 3D CAD modeller från Pro/E, utfört av Applied Mechanics Group.
Syftet är även att identifiera och definiera vanliga problem. Målet med detta examensarbete är
att utveckla en arbetsmetod för att förenkla överföringen av modeller skapade i Pro/E till
ANSYS, för att spara tid och resurser för Applied Mechanics Group.
För att uppnå målet skapades en checklista som kan användas som en hjälpsam guide under
projekt som kräver analys i ANSYS. Den innehåller även riktlinjer med tips för konstruktörer
som arbetar i Pro/E. Checklistan ger möjlighet till bättre kommunikation och förståelse
mellan Applied Mechanics Group och konstruktörer som arbetar i Pro/E.
Varje punkt på checklistan bygger på resultat av tester och information från deltagarna som
medverkat. Den första bilagan i checklistan är en jämförelse av lösningar i Pro/E och ANSYS
och även rekommendationer för vart modellerna lättast går att ändra. Den andra bilagan är
riktlinjerna med tips för konstruktörer som modellerar i Pro/E. I dessa riktlinjer finns ett
dokument bifogat med mer detaljerad information kring några av ämnena.
Den skapade arbetsmetoden kan användas som en gemensam grund att utgå ifrån och är ett
levande dokument att uppdatera. Jag rekommenderar att samtliga av de tre dokumenten
används i projektet för att få ut så mycket som möjligt av denna arbetsmetod.
Frida Arnesson
Juni 2011
Örebro
Handledare: Sören Hilmerby
Examinator: Johan Kjellander
Nyckelord: CAX, CAD, Pro/ENGINEER, ANSYS
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
3(29)
ACKNOWLEDGEMENTS
I want to thank my supervisors at Atlas Copco AB; Maria Åberg, CAD & PDM Application
Engineer and Hanna Kristoffersson, Specialist – Mechanical Analysis.
I want to thank You both for all support and guidance that You have given me.
Also, I want to thank Sören Hilmerby, lecturer in mechanical engineering, my supervisor at
Örebro University, for guidance and support.
I would like to thank all of the people that have participated in interviews, meetings and the
questionnaire. I am also grateful to all the people that I have asked questions to.
You have all been very helpful by sharing Your valuable knowledge and You have been very
positive and have been trying to do Your best to answer my questions.
Last, but not least, I want to thank my family for always supporting me.
I would never have been able to accomplish the thesis without all of Your help.
Thank You.
Frida Arnesson
Örebro
June 2011
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
4(29)
Table of Contents
ABSTRACT................................................................................................................... 1
SAMMANFATTNING ................................................................................................. 2
ACKNOWLEDGEMENTS ......................................................................................... 3
TABLE OF CONTENTS ............................................................................................. 4
TABLE OF FIGURES.................................................................................................. 5
ABBREVIATIONS ....................................................................................................... 6
1 INTRODUCTION...................................................................................................... 7
1.1 BACKGROUND ........................................................................................................................... 7
1.1.1
Problem ......................................................................................................................... 8
1.1.2
Description of ANSYS.................................................................................................. 8
1.1 PURPOSE .................................................................................................................................... 10
1.2 OBJECTIVES.............................................................................................................................. 10
1.3 DELIMITATIONS ...................................................................................................................... 10
2 WORK METHOD ................................................................................................... 11
2.1 QUESTIONNAIRE ..................................................................................................................... 12
2.1.1
Results and conclusions of the questionnaire.............................................................. 13
2.2 INTERVIEWS AND MEETINGS .............................................................................................. 14
2.2.1
Results and conclusions of the meetings and interviews............................................. 15
2.3 TESTS ......................................................................................................................................... 17
2.3.1
File formats ................................................................................................................. 17
2.3.2
Typical problems......................................................................................................... 19
2.3.3
Difficult problems ....................................................................................................... 20
3 RESULTS AND DISCUSSION .............................................................................. 23
3.1 DISCUSSION.............................................................................................................................. 23
3.2 CONCLUSIONS ......................................................................................................................... 26
FURTHER COMMENTS AND SUGGESTIONS ............................................................................ 27
4 REFERENCES ......................................................................................................... 28
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
5(29)
5 APPENDICES .......................................................................................................... 29
APPENDIX A – QUESTIONNAIRE ................................................................................................ 29
APPENDIX B – QUESTIONNAIRE RESULTS.............................................................................. 29
APPENDIX C – COMPARISON OF SOLUTIONS IN PRO/E AND ANSYS................................ 29
APPENDIX D – COMPARISON OF STEP – AND PARASOLID FORMAT................................ 29
APPENDIX E – CHECKLIST........................................................................................................... 29
APPENDIX F – GUIDELINES FOR MODELLING IN PRO/E ...................................................... 29
APPENDIX G – DETAILED INFORMATION ............................................................................... 29
Table of Figures
Figure 1: Atlas Copco in Örebro ................................................................................................ 7
Figure 2: ANSYS Workbench.................................................................................................... 8
Figure 3: ANSYS DesignModeler ............................................................................................. 9
Figure 4: ANSYS Classic........................................................................................................... 9
Figure 5: Questionnaire results ................................................................................................ 13
Figure 6: Parasolid and STEP .................................................................................................. 17
Figure 7: Problems with Parasolid ........................................................................................... 18
Figure 8: Bending radii ............................................................................................................ 20
Figure 9: Instructions to change measurement accuracy in ANSYS ....................................... 22
Figure 10: Project participants’ responsibility area.................................................................. 24
Figure 11: Areas to pay attention to ......................................................................................... 24
Figure 12: Areas to pay extra attention to ................................................................................ 24
Figure 13: The two appendices to the checklist ....................................................................... 25
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
6(29)
Abbreviations
RDE:
CMT:
SDE:
URE:
TME:
SES:
Atlas Copco Rock Drills AB
Construction and Mining Technique
Surface Drilling Equipment
Underground Rock Excavation
Tunnelling and Mining Equipment
Specialist Engineering Services
CAX:
PDM:
CAD:
3D CAD:
Computer Aided Technologies, i.e. CAD (Pro/ENGINEER, AutoCAD) and CAE (ANSYS)
Product Data Management, (DEMO, Intralink, Drawing Archive)
Computer Aided Design
Pro/E
Pro/E:
PTC:
ANSYS:
PTC 3D CAD program Pro/ENGINEER Wildfire 4
The company PTC - Parametric Technology Corporation.
Simulation and analysis program ANSYS version 13.0
EDR:
APDL:
The ANSYS supplier of Atlas Copco, in Gothenburg
ANSYS Parametric Design Language
FEA:
GUI:
DEMO:
Finite Element Analysis
Graphical User Interface
Atlas Copco developed software, that contains all structures and
Bill of Material lists
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
7(29)
1 Introduction
1.1 Background
Atlas Copco Rock Dills AB (RDE) in Örebro is part of the Atlas Copco Group Construction
and Mining Technique (CMT) business area. RDE is divided in three divisions: Rocktec,
Surface Drilling Equipment and Underground Rock Excavation. The products are used in
tunnel and mining industries all over the world.
Rocktec is the development centre for CMT. Rocktec has three departments: Rock Drills,
Automation and Specialist Engineering Services (SES). SES provides consultancy to all of
CMT, and is divided in specialist groups like Industrial Design, Measurements Technique and
Patents. The thesis is in cooperation with the CAX & PDM Solutions group and the Applied
Mechanics Group at the division Rocktec at RDE, see figure 1.
Atlas Copco
Rock Drills AB
(RDE)
Surface
Drilling
Equipment
(SDE)
Rocktec (RTE)
Underground
Rock
Excavation
(URE)
Specialist Engineering
Services (SES)
CAX & PDM
Solutions
Applied
Mechanics
Group
Figure 1: Atlas Copco in Örebro
The CAX & PDM Solutions group work as user support for CAX and PDM software, such as
Pro/E and Intralink. The group develops work methods and system training, and handles
licensing for the CAX and PDM software.
The Applied Mechanics Group creates solutions to technical problems through analytical and
numerical analyses with software such as ANSYS. The group develops work methods to
optimize their analyses and performs tests in their laboratory.
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
8(29)
1.1.1 Problem
The Applied Mechanics Group uses, among several programs, ANSYS software to simulate
and analyze loads, and they often import 3D CAD models created in Pro/E. However, they
often have to modify the models to be able to use them in ANSYS, and sometimes they have
to create new models because the way the model is created in Pro/E makes it impossible to
use in ANSYS. The process is extensive and all the modifications take long time to make. To
solve the problems and facilitate the process would therefore be timesaving. This would also
lead to better communication between the Applied Mechanics Group and the Mechanical
Designers that work in Pro/E, but also to increase the understanding between them and how
they work in Pro/E and/or ANSYS in different ways.
1.1.2 Description of ANSYS
The ANSYS software can be used for numerous kinds of analysis such as structural, modal
and harmonic response. It is a FEA software from the USA and has been used for 40 years.
The software has two platforms; ANSYS Workbench and ANSYS Mechanical APDL,
formerly known as ANSYS Classic. In this report the ANSYS Mechanical APDL will be
referred to as ANSYS Classic since that is the common expression at Atlas Copco AB.
The ANSYS Workbench platform is an advanced simulation tool. The analysis is overviewed
with a drag- and- drop system, see figure 2. (1) It’s built on ANSYS Classic.
Figure 2: ANSYS Workbench
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
9(29)
ANSYS Workbench has a CAD connection; ANSYS DesignModeler. By using that
connection, a model can be built from scratch, but can also be imported from another CAD
system, regenerated and updated to simplify the model for analysis. (2)
Figure 3: ANSYS DesignModeler
ANSYS Classic is the other platform and the user interface is quite different than Workbench,
even though Workbench is built on ANSYS Classic.
The biggest differences are that the Classic platform uses scripts (commands in APDL) to
create geometries, elements and nodes. The models can also be generated manually by a
simpler form of GUI. (3) It’s possible to connect these two platforms, which makes it possible
to work with a model in both platforms. See figure 4.
Figure 4: ANSYS Classic
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
10(29)
1.1 Purpose
The purpose of this thesis is:
To document the current work performed by the Applied Mechanics Group when they import
3D CAD models created in Pro/E.
To identify and define common problems in association with the transfer of models from
Pro/E to ANSYS.
To facilitate the transfer of the 3D CAD models from Pro/E to ANSYS by documenting
different ways to modify the models by the Mechanical Designers.
1.2 Objectives
The objectives for this thesis are:
To develop work methods for creating models in Pro/E that facilitates the import of the
models to ANSYS, thus saving time and effort for the Applied Mechanics Group.
To create a checklist to facilitate the import of 3D models and also to create guidelines for
Mechanical Designers that work in Pro/E.
1.3 Delimitations
The thesis will only include the export of 3D models created in Pro/E to ANSYS, no other
software.
It was decided in cooperation with the Applied Mechanics Group and CAX & PDM Solutions
at RDE that only one work method will be developed.
The work method will be a general solution to facilitate the transfer from Pro/E to ANSYS.
The result won’t be a specific solution for all users’ specific requirements of ANSYS and
Pro/E.
The depth of documentation depended on how specific each problem and solution had to be
defined, which was decided during the current state analysis.
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
11(29)
2 Work method
This thesis is made at the department for CAX & PDM solutions and at the Applied
Mechanics Group at Rocktec. It will investigate how the 3D CAD models are created in Pro/E
and imported to ANSYS today and also identify common problems. The objective with this
thesis is to create work methods to simplify the transfer from Pro/E to ANSYS.
The thesis is based on knowledge from the Mechanical Designers and Structural Analysists
that daily uses the both software. The equivalent knowledge can not be collected elsewhere,
depending on the lack of documentation that concerns the problems with the transfer from
Pro/E to ANSYS.
An initial meeting with the Applied Mechanics Group generated an overview of the problems
that often occur, but also a decision that the thesis will result in a checklist. The checklist may
be used as a common ground to start from at initial meetings of Atlas Copco’s projects but
also during the entire project. It was decided that guidelines will be created with tips for
Mechanical Designers that work in Pro/E.
During the meeting it was established that there are different ways to import 3D CAD models
from Pro/E and to analyse them in ANSYS and also how the Mechanical Designers make
modifications in the model. The models can be modified in both Pro/E, ANSYS
DesignModeler or in ANSYS Classic.
It was decided to perform interviews and meetings in an early state, approximately in the 1st
and 2nd week of the thesis. The information gathered will be the ground for the current state
analysis. In addition to the meetings and interviews, it was decided that a questionnaire would
be used to chart the problems and to document the current work methods.
The meeting also generated some suggested topics to the questionnaire and also interested
participants who had the right qualifications.
The appendices A – D are written in Swedish, while the appendices E – G are written in
English. The Swedish appendices’ titles are translated, see Appendices.
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
12(29)
2.1 Questionnaire
The questions to the questionnaire were developed in agreement with Hanna Kristoffersson at
Applied Mechanics Group.
The questions were divided in two topics; Transfer and General modelling. The questions
were asked to chart how Pro/E and ANSYS are most frequently used, but also to define the
most common problems.
There were also questions to identify if any of the file formats is easier to transfer than the
other and if any format causes fewer problems than the other.
To be able to compare the transfer improvements before and after the created checklist, the
participants also had to estimate the frequency of specific problems and the time they spend to
correct the problems.
The questionnaire is shown in Appendix A.
The questionnaire was answered by the following:
Applied Mechanics Group, RTE
Kenneth Weddfelt, Group Manager
Eva Hyvärinen, Specialist Mechanical Analysis
Jari Hyvärinen, Specialist Mechanical Analysis
Hanna Kristoffersson, Specialist Mechanical Analysis
Anita Sandström, Specialist Mechanical Analysis
Gunnar Sjödin, Specialist Mechanical Analysis
SDE
Niclas Andersson, Mechanical Designer
Per Elvén, Mechanical Designer
URE
Andreas Nordh, Mechanical Designer
Bengt Borgström, Mechanical Designer
Björn Ryttare, Specialist Structural Analysis
Kenneth Granath, Specialist Mechanical Analysis
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
13(29)
2.1.1 Results and conclusions of the questionnaire
As result of the questionnaire, the most common problems were listed with an estimation of
frequency. The most common problems are shown and listed in figure 5 and the total result is
shown in Appendix B.
The estimation of how much time in minutes that the participants use to correct models and to
solve problems proved difficult to make, and were therefore excluded from the result.
Figure 5: Questionnaire results
However, to estimate a percentage of the total time working with a model spent on
modifications was easier. The average time spent on solving problems with the model was
23 % of the total working time.
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
14(29)
Conclusions of the questionnaire were summarized and generated the following decisions:
• Not to proceed with the file format “IGES”, because the format is not frequently used.
• To proceed with the file format “STEP”. It causes a lot of problems.
• To make a comparison between the file format “Parasolid” and “STEP”, since some
indications were made that (4) some problems are possible to avoid with Parasolid
instead of STEP. That will be investigated, even though Parasolid is not frequently
used either.
• To pay extra attention to bending radii, welds, accuracy/tolerances and external
references. How deeply they will be explained will depend on the time left.
• To give suggestions for future work. The number of suggestions will depend on the
time left.
2.2 Interviews and meetings
Interviews were performed with the participants in association with the questionnaire, except
for the Applied Mechanics Group where only Hanna Kristoffersson was interviewed.
The interviews were performed to chart the most common problems with the transfer of 3D
CAD models, but also to understand how the Mechanical Designers and Structural Analysists
work differently with the modelling and the analysis in Pro/E and ANSYS.
The interviewees were chosen in collaboration with Maria Åberg and members of the Applied
Mechanics Group at the initial meeting. Structural Analysists and Mechanical Designers were
chosen, to give perspectives from different points of views to the issue. Some of the
interviewees also have knowledge in both Pro/E and ANSYS, which was helpful to get an
overview of the problems.
An interview with David Sjölander at EDR, was also performed to answer general questions
about ANSYS, to chart advantages and disadvantages with the software and to answer if there
are any theories about the different file formats and to receive useful tips.
The interviewees were the following:
Applied Mechanics Group, RTE
Hanna Kristoffersson, Specialist Mechanical Analysis
SDE
Niclas Andersson, Mechanical Designer
Per Elvén, Mechanical Designer
URE
Andreas Nordh, Mechanical Designer
Bengt Borgström, Mechanical Designer
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
15(29)
Björn Ryttare, Specialist Structural Analysis
Kenneth Granath, Specialist Mechanical Analysis
Markus Rantakeisu, Mechanical Designer
EDR – ANSYS Supplier
David Sjölander
The Specialist Mechanical Analysis is in average the same as Specialist Structural Analysis or
Structural Analysist, of which Structural Analysist will be used in this report as a title for all
of them. The different titles depend on which group or division the Structural Analysist work
at.
2.2.1 Results and conclusions of the meetings and interviews
The following results and conclusions could be summarized after the interviews and
meetings:
Test 1
It is necessary to increase the understanding between the Mechanical Designers that model in
Pro/E and the Structural Analysist that work with the models in ANSYS, so they understand
what they can do to simplify the transfer and the analysis. In which software the models will
be modified has to be decided in the beginning of each project, so all participants know their
responsibilities, what to expect and what to do. To be able to do that, it was decided to
perform a test, to generate a comparison of how modifications are made in both Pro/E and in
ANSYS.
Conclusions from the comparison result will generate recommendations of which software to
use. The document will have a recommended solution for a new project and another for the
project with already existing models.
Test 2
The interview with David Sjölander at EDR generated the thought that models in Parasolid
format could solve some of the issues with the models, because the ANSYS DesignModeler is
built on a Parasolid kernel (2).
A simple test of file formats will be performed to investigate if the theory (2) is true and
thereby investigate if models in Parasolid format create fewer problems than models in STEP
format.
Test 3
In connection with test 2, it was discovered that there are different ways to open a Parasolid
file in ANSYS. The test 3 was performed to test the difference between computers with
ANSYS 13.0 installed with the Parasolid option and without the option.
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
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16(29)
Difficult problems
There are some particular problems that have to be investigated:
•
Problems with welds are difficult to solve in both Pro/E and ANSYS.
•
Problems with bending radii are also difficult to solve in both Pro/E and ANSYS.
•
External references in Pro/E must be avoided. They create a lot of problems in
ANSYS.
•
The accuracy in Pro/E may create gaps and problems in ANSYS; what is preferable of
relative and absolute accuracy in Pro/E?
There are two different scenarios where the checklist can be used:
• A new project where all the models will be created from the start.
• A project with already existing models.
You need to consider how the scenario will affect the use of the checklist and make a note of
it in the checklist.
What are the differences between the projects?
New project
The Mechanical Designer creates 3D models from the beginning. The models are often
updated, therefore there would be an advantage to make a correct model from the beginning
and to create them directly in Pro/E.
Project with already existing 3D CAD models
In some ways models that already exist are more complicated than new models, because new
models can be modelled to work better in ANSYS from the start. Existing models usually
needs to be modified to work properly in ANSYS.
One of the participants who work in both Pro/E and ANSYS said that the software DEMO is
very useful to make sure that the latest version and revision are in use. The suggestion about
that software is not useful in this thesis, because the Structural Analysists do not know how to
use that software.
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
17(29)
2.3 Tests
2.3.1 File formats
Test of Parasolid- and STEP format and a comparison between them
The results of the interviews indicated that most of the Structural Analysists use Workbench
and the file format “STEP” (.stp) and while using that format, a lot of problems occur.
As earlier mentioned, both David Sjölander and theory (2) said that the Parasolid format can
solve issues with models. The solution was according to David Sjölander, to convert the
model to Parasolid format instead of STEP format. A test was performed to investigate if the
model’s format would make any differences and confirm the theories.
The simple test was performed with four different models. First the model was opened in
ANSYS DesignModeler in STEP format and then the procedure was repeated but with the
model in Parasolid format instead. Pictures were taken and differences were checked up.
The test models had different part numbers;
• A stag with 3 parts
• A steering anchor with 24 parts
• A cab with 133 parts
• A power frame with 119 parts
The total result of the test is shown in Appendix D.
Figure 6: Parasolid and STEP
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Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
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The stag and the steering anchor did not generate any problems at all, neither in STEP nor in
Parasolid format. Both the cab and the power frame generated problems in Parasolid format,
but did not generate any problems in STEP format.
The cab lost parts in the Parasolid format; while it had 133 parts in the STEP format, the
model had only 101 parts in Parasolid format.
The power frame lost parts and got double volumes in the Parasolid format, see figure 7.
Double volumes
Missing parts
Figure 7: Problems with Parasolid
According to the performed test and one of the questionnaire participants that uses models in
Parasolid format, double volumes and missing parts are common problems with Parasolid
format. Tests were performed to see if smaller assemblies had as many problems as the big
ones.
The tests proved that these problems occur more often in association with big and complex
models and that smaller assemblies cause fewer problems with both STEP - and Parasolid
format. The result is shown in Appendix D.
The conclusion of this test and the questionnaire results are that both Parasolid- and STEP –
formats are unstable and that they both generate problems. The Structural Analysists may
choose any of the file formats, the one they prefer. The performed test proved that Parasolid
generate problems, while STEP did not. But the questionnaire results clearly stated that STEP
is a common format and that it causes a lot of problem, even though the performed test has
not caused any.
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
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One of the reasons why the both file formats are so unstable may depend on where the files
are created. This thought has not been investigated furthered because of the limited amount of
time.
A question came up; would the test results be different if the ANSYS software has the
Parasolid option. That question generated the next test.
Test of a computer with ANSYS 13.0, without the Parasolid - option chosen and another
computer with the Parasolid – option chosen
The test result is also shown in Appendix D. A computer with ANSYS 13.0 can have some
different licenses installed and different options chosen. Among those, there is a choice about
Parasolid format. In the following test, both computers had the licences for Parasolid installed
but the options for Parasolid differed.
The test was performed through opening the model in Parasolid format in ANSYS
DesignModeler and to investigate if any problem occurred. The test was performed at a
computer with ANSYS 13.0 installed without the Parasolid option chosen and another
computer with the Parasolid option chosen. The test was performed to investigate if the option
would make any difference of the result of the models in Parasolid format.
The stag and the steering anchor models did not generate any problems, neither with the
Parasolid option chosen nor without it.
The power frame responded to both of the tests with the same problems as the test before
generated, shown in figure 7. Both the double volumes and missing parts occurred at the
computer with the Parasolid option and at the computer without the option.
The cab model responded to both of the tests with the same results as the test before
generated, shown in figure 6. The model lost parts and got double volumes.
The conclusion of this test is that a computer with ANSYS 13.0 installed with the Parasolid
option, do not facilitate the transfer of models in Parasolid format from Pro/E to ANSYS,
compared to a computer without the Parasolid option.
2.3.2 Typical problems
Test of different solutions in ANSYS and Pro/E
A test was performed to investigate how modifications are made in ANSYS and in Pro/E. The
problems that the questionnaire participants said most often occur in STEP format were listed.
Then solutions were created in first ANSYS and then Pro/E.
The result of the tests is shown in the test protocol in Appendix C, where a comparison is
made. The comparison shows how many steps the user has to make to solve a problem in
Pro/E compared to ANSYS. A recommended choice was made; one for new projects and one
for projects with already existing models. There are also comments and pictures of typical
examples for each problem.
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
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The conclusion of this test is that the recommended solution mostly depends on what type of
project the model is used in. The comparison can be used as a helpful guide to help the project
participants decide what problems to solve in which software. It can also help them to decide
the participants’ responsibility areas, according to what software that are used to solve
different problems.
2.3.3 Difficult problems
As earlier mentioned, some problems are more difficult to solve than others:
Welds: The models are very often created for production and not for analysis. Because of
that, the welds are not modelled at all. Instead of the modelled welds, gaps are created in the
model.
These gaps have to be filled out to create contact between the geometries in ANSYS
Workbench. This can be done in both Pro/E and ANSYS Workbench, see Appendix C.
For some interviewees the welds are difficult to handle because they want the welds and
plates as different parts/volumes. It is common to handle the welds in ANSYS Classic. But
even if the parts look like they are put together, the tolerances in Pro/E put the surfaces in
different planes. Because of that, the Structural Analysist can not connect the parts, so that the
parts share the same surface.
One of the reasons that this problem exists could be that the accuracy and tolerances in Pro/E
are not accurate enough. There are different solutions that depends on each Mechanical
Designer and what model they work with. This reason has not been investigated much further,
because of the limited amount of time.
Bending radii: A general solution is difficult to create, for
solving problems with bending radius. There are especially
difficult to create two radii, which follow each other and have
the same bending angle. See example in figure 8.
Figure 8: Bending radii
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
External References: An instruction should be created that indicates that using external
references is not allowed if the 3D CAD model is going to be transferred to ANSYS. The
reason is that external references create problems in ANSYS. See example in figure 9.
Pro/E model
Result in ANSYS. The sideplates of the boom are not transferred correctly as a consequence of the external references:
Figure 9: External References
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Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
22(29)
Tolerances and accuracy: Pro/E has by default the relative accuracy set to 0.0012. (4) & (5).
That means that Pro/E never gives accuracy that is exactly 0, which creates very small
distances between parts. This may create problems and gaps in ANSYS.
There might be a possible way to avoid these problems:
•
Change the relative accuracy to absolute accuracy in Pro/E. See instructions in
Appendix G.
According to EDR, it is possible to change the accuracy in ANSYS too, but only the
measurement accuracy to either “Low”, “Normal” or “High”. Go to the window
DesignModeler and go to Tools and choose Options. See instructions in figure 10.
Figure 9: Instructions to change measurement accuracy in ANSYS
The conclusion of all the difficult problems is that the solutions have to be created
individually, depending from model to model. Another conclusion is that guidelines regarding
these problems are necessary. The guidelines with tips and more information about them are
shown in Appendix F and in Appendix G. Some of these problems are also suggested for
further work, to investigate the problems deeper.
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
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23(29)
3 Results and Discussion
3.1 Discussion
From the results and conclusions, I created a checklist to be used as a helpful guide during the
entire project, see Appendix E. It should be used in agreement with all the project’s
participants as a common ground to start from. The intention is to avoid misunderstanding
and facilitate communication. I also created guidelines for the Mechanical Designers that
work in Pro/E, see Appendix F and G.
The checklist and guidelines have not been tested in any project yet and therefore it is difficult
to tell how it will work exactly. This is how I would like it to work:
At the start of the project, the project group goes through the checklist. They cross the boxes
for every part of the checklist that applies to their project and use the space on the right to
make notes if necessary. The thought is to use the checklist to make sure that no relevant
subject is forgotten and to use it as a support to decide the responsibilities.
The guidelines are notes and practical tips to be used to help Mechanical Designers with
models that are going to be transferred to ANSYS.
All of the areas in the checklist are based on what the questionnaire- and meeting participants
have brought up and also based on conclusions that I have drawn from the different tests.
The questionnaire result indicated that everybody is working in different ways with the
transfer of models from Pro/E to ANSYS. A result from the interviews is that everybody
wants to continue their individual work. I think that there is no need for everybody to work in
the same way. The created checklist allows the project participants to keep their individual
work with the models but makes them have a common ground to start from.
As earlier mentioned, the intention is to avoid misunderstandings and to facilitate
communication, which hopefully leads to fewer problems with the imported models.
The meetings and interviews indicated that most of the Structural Analysists always try to
solve the problems in ANSYS by themselves without any communication with the
Mechanical Designer that created the model. The checklist will hopefully reduce their
problems through making the Mechanical Designers that create models in Pro/E, aware of
how they can create better models for analysis.
It is important that everybody in the project knows how to use the checklist and that they
understand how it can facilitate the project process.
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
24(29)
It is also valuable to know how all participants want to work. This can be answered in the first
part of the checklist, through answering the questions:
•
•
•
Are there any guiding principles to follow?
How will the versions be updated?
How do the Structural Analysists want to have their models when they import them
from Pro/E to ANSYS?
After those decisions, it is time to move forward to what responsibilities that everybody has,
but also to answer what parts that will be particularly difficult to solve in the models.
Who is responsible, at what point in the project will the problem be addressed and in which
software will the problem be solved? Those questions are meant to be discussed together
while using the checklist’s second part.
Figure 10: Project participants’ responsibility area
All of the subjects listed in figure 11 and 12, are results of what the questionnaire and
interviews have indicated are common problems but also areas that are complicated and
problems difficult to model. For the Mechanical Designers that are interested of the areas
listed under “Pay extra attention to”, they have more detailed explanations in the guidelines
and Appendix G.
Figure 11: Areas to pay attention to
Figure 12: Areas to pay extra attention to
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
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As earlier mentioned, the first appendix is created from conclusions from test results, see 2.3
Tests. The other appendix is the guidelines that I have created from conclusions from the
results of both the interviews, meetings and questionnaire.
Figure 13: The two appendices to the checklist
To help the users of the checklist decide in which software that they will perform
modifications best and most easily, the first appendix is the comparison between solutions in
Pro/E and ANSYS, see Appendix C.
The guidelines are supposed to be easy to handle and the information is not very deeply
explained. That is one of the main reasons why the Appendix G is necessary, for those
Mechanical Designers who want to know more about specific problems.
The Appendix G has some of the areas from the guidelines explained more detailed. The
selected areas from the guidelines are:
• Tolerances and accuracy
• Geometry Checks
• Mapkeys
• Modelling
I decided to have the information in a separate document and not together with the guidelines
to make the guidelines easier to use. If the information is not enough in the document, there
are suggested references and other reliable sources.
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
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26(29)
3.2 Conclusions
I think that the created work method can work as a common ground to start from and that it
will be a living document that can be updated, when the documents, the software and the
communication within the company develop.
This work method is created to increase the knowledge about the transfer of 3D CAD models
from Pro/E to ANSYS. It is also created to increase the understanding and the communication
between the Structural Analysists and the Mechanical Designers that work in Pro/E. The
documents may be brought to the projects meetings at Atlas Copco where it will be decided
for each project what parts of the checklist that applies to that project.
I think that all of the three documents are necessary to get the most out of the work method
that I have created. Even if the user does not have any problems with the subjects in the
Appendix G, it is a document good to have beside you if the problem would come up. The
document can be developed through adding other problems that can be explained further.
In the future I hope that the checklist will be used at every project meeting and that
Mechanical Designers that work in Pro/E will use the guidelines to get information and tips
about the modelling.
As earlier mentioned in the delimitations the work method is a general one. I am sure that
more individual work methods within this area can be developed in future.
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
27(29)
Further comments and suggestions
The time was limited and not enough to investigate everything that came up along the work
with the thesis. I think that the following areas would be interesting to investigate deeper in
future:
Follow – up
Send out the questionnaire to chart what kind of problems that still occur after using the
checklist and the guidelines. This is a good way to follow up the results of the thesis and to
see if the results have created a solution that actually facilitates the transfer.
Layers
One of the interviewees talked about layers and if there would be possible to create a layer in
the model with all parts that starts with for example “03”. It would be interesting to see if
there would be possible to suppress layers.
Sheet metal
In the end of the thesis, participants of the questionnaire talked about the sheet metal function
in Pro/E. If this function is used to create a model for analysis, it may create problems in
ANSYS. I would recommend investigating the sheet metal tool closer to chart the problems
and how frequent they occur.
Tolerances and accuracy
The result of changing the relative accuracy to absolute has not been investigated enough. I
would recommend an investigation to see how the change of accuracy affects the 3D CAD
models from Pro/E, in ANSYS.
Welds
A best practice for how to create and handle welds does not exist according to some of the
questionnaire participants. It would be interesting to investigate the possibilities to simplify
the problems about the welds.
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
Page
28(29)
4 References
(1) “ANSYS Workbench platform”. Retrieved May 3, 2011, from:
http://www.ansys.com/Products/Workflow+Technology/ANSYS+Workbench+Platfor
m
(2) “ANSYS DesignModeler”. Retrieved May 3, 2011, from:
http://www.ansys.com/Products/Workflow+Technology/ANSYS+Workbench+Platfor
m/ANSYS+DesignModeler
(3) “ANSYS, Inc. Release Notes”. Release 12.0 April 2009. Retrieved May 3, 2011, from:
http://www1.ansys.com/customer/content/documentation/120/ai_rn.pdf
(4) Kudzma, J. “Accuracy”. PTC - Parametric Technology Corporation. Retrieved May
4, 2011, from:
http://www.proesite.com/accuracy.htm
(5) “General Information Regarding Geometry Checks (Geom Checks)”. PTC Parametric Technology Corporation. Retrieved May 5, 2011, from:
https://www.ptc.com/appserver/cs/view/solution.jsp?n=105892
© Atlas Copco Rock Drills AB
This document is our property and shall not without our permission be altered, copied, used for manufacturing or communicated to other person or company.
Thesis:
Work method to simplify transfer of 3D models to ANSYS for
analysis at Atlas Copco Rock Drills AB
Issued by
Product
Document no
Anna Lofgren
General
TD2011-0377
Department Area
Project
Technical Support a) General
D5011
Research/högskola
Approved by
Date
Maria Åberg
2011-05-24
5 Appendices
Appendices A - D are in Swedish and appendices E – G are in English.
Appendix A – Questionnaire
Frågeformulär
Appendix B – Questionnaire results
Resultat av frågeformulär
Appendix C – Comparison of solutions in Pro/E and ANSYS
Jämförelse av lösningar i Pro/E och ANSYS
Appendix D – Comparison of STEP – and Parasolid format
Jämförelse mellan STEP – och Parasolidformat
Appendix E – Checklist
Checklista
Appendix F – Guidelines for modelling in Pro/E
Riktlinjer med tips i Pro/E
Appendix G – Detailed information
Detaljerad information
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Appendix A – Questionnaire
Frågeformulär
Appendix B – Questionnaire results (result of q. 4, see last page in this
Appendix)
Resultat av frågeformulär (för sammanställning av fråga 4, se sista sidan i detta Appendix)
Question 4, results:
STEP - fil
Upplevs detta?
Frekvens (1-10)
Medelfrekvens
4
4
30
5, 7
6
V III
V II
15-30, 30, 5, 5, 30, 5-30
15-30, 15, 5, 10, 30, 5-30
3, 8, 3, 2, 3, 4, 8, 2
3, 10, 4, 3, 2, 9, 2
4,125
4,714
I
10
8
8
I
60
10
10
Volym er flyttar på sig
I
Dubbla ytor skapas
En volym är inte solid (endast
ytterskal)
Parter kommer inte m ed
II
Övriga fel, t ex: Dubbla volym er
Går ej att få bort nedsäkningar
kring hål, gängor på ett enkelt
sätt
Tid (min)
Parasolid (Endast 1
användare)
Upplevs detta?
Volym er flyttar på sig
Dubbla ytor skapas
En volym är inte solid (endast
ytterskal)
Parter kommer inte m ed
Övriga fel, t ex: Fogberedning
Tid (min)
Frekvens (1-10)
Medelfrekvens
I
I
15
10
5
2
5
2
I
I
I
30
10
30
2
2
2
2
2
2
Tid (min)
Frekvens (1-10)
Medelfrekvens
15-30
15-30, 10
3
2,1
3
1,5
Tid (min)
Frekvens (1-10)
Medelfrekvens
I
5 tim
5
5
III
I
5, 10 tim, 5-30
10
3, 10, 2
3
5
3
Pro/E-assembly
Upplevs detta?
Volym er flyttar på sig
Dubbla ytor skapas
En volym är inte solid (endast
ytterskal)
Parter kommer inte m ed
Övriga fel, t ex:
I
II
IGES (Endast 3 användare)
Upplevs detta?
Volym er flyttar på sig
Dubbla ytor skapas
En volym är inte solid (endast
ytterskal)
Parter kommer inte m ed
Övriga fel, t ex:
Den solid som skapas går ej att
använda bolskt på ?
Längre
Appendix C – Comparison of solutions in Pro/E and ANSYS
Jämförelse av lösningar i Pro/E och ANSYS
Lösningar av problem i ANSYS och Pro/E, i ett nytt resp. befintligt projekt
Problem
ANSYS
Pro/E
Features
Face delete
Markera valda objekt
(Ev slice eller subtract)
2-3
Suppress feature
Antal steg
Rekommendation; Nytt projekt
Rekommendation; Befintligt projekt
1
Pro/E
Pro/E eller ANSYS
Nytt projekt:Suppress features i Pro/E är oftast
men inte alltid enklare. Detta kräver att parten är
korrekt konstruerad dvs med alla features lagda
sist i modellträdet.
Befintligt projekt: ANSYS kan lika gärna
användas som Pro/E. Vart problemet skall lösas
bestäms i samförstånd mellan beräkningsingenjör
och konstruktör.
2. Nedsänkning av hål
3. Onödiga hål
Problem
ANSYS
Glapp
Skapa plan
Pro/E
Om glappet ligger i "ett plan" (tex 90 grader mot
den plåt den skall extruderas emot) kan det räcka
med 1 steg för detta.
Om plåten däremot lutar i en eller flera riktningar
krävs det minst 2 steg (tex definiera om sketchen
plus ett cut efteråt.)
Kommentar
Exempel
1. Faser
Extrudera mot yta
(Ev skära till m h a Freeze, slice, suppress,
merge)
Antal steg
2-6
Rekommendation; Nytt projekt
Pro/E
Rekommendation; Befintligt projekt
Pro/E eller ANSYS
Nytt projekt: Det kan förekomma många glapp
och jag rekommenderar att redan från början rätta
till dessa i Pro/E. Man behöver inte alltid
Befintligt projekt: I vilket program problemet
extrudera, utan glappet kan bero på att en part
inte är rätt placerad i assemblyn, vilket kan
skall lösas bestäms i samförstånd mellan
regleras.
beräkningsingenjör och konstruktör.
Kommentar
Exempel
1-2
Problem
ANSYS
Pro/E
Komplicerade hörn/kanter
Extrudera
Freeze
Slice
Merge
4
Skapa en part av de inblandade parterna
Ofta väldigt krångligt
Svårighetsgraden varierar från fall till fall.
Antal steg
Rekommendation; Nytt projekt
Rekommendation; Befintligt projekt
Kommentar
Exempel
Fler än 5
Pro/E
Pro/E eller ANSYS
Nytt projekt: ProE rekommenderas, eftersom att
det är mer värdefullt att rätta till problemet så att Befintligt projekt: ANSYS kan användas istället
den tillrättade parten alltid följer med
för Pro/E. Detta bestäms i samförstånd mellan
uppdateringen av versionerna.
beräkningsingenjör och konstruktör.
Problem
ANSYS
Pro/E
Parter sitter inte ihop
Merge
Alt.1 - Rita om sketchen i ena parten - 1 steg
Alt. 2 - fylla glappet med en extrude i ena parten kan räcka med 1 steg, men kan bli fler än 3.
Antal steg
1
1-3
Rekommendation; Nytt projekt
Rekommendation; Befintligt projekt
Pro/E
ANSYS
Nytt projekt: Det är bra även här om man gör
"rätt från början" i Pro/E, så att den följer med
alla uppdaterade versioner. Ifall man utför detta i
ANSYS, måste man t ex göra om detta varje
Befintligt projekt: ANSYS rekommenderas då det
gång en version uppdateras.
oftast är enklare än Pro/E.
Kommentar
Exempel
Svårlösta problem
ANSYS
Pro/E
Lika krångligt som i Pro/E
Antal steg variererar beroende av hur modellen
ser ut. Har man en krånglig geometri är det
oftast lättast att rita en ny geometri som en
enda part. Då blir troligen beräkningsmodellen
stabilare/ enklare. Det är annars svårt att få
radier som ligger an mot varandra att mötas
bra, bl.a. p.g.a. noggrannheten i Pro/E (radierna
blir inte exakt runda). Se bild nedan.
Parter med externa referenser
Parterna hänger inte med från Pro/E
De är inte tillåtna om man skall importera en
Pro/E-geometri direkt (utan att gå via tex step),
då externa referenser alltid orsakar problem. Se
bilder på nästa sida.
Toleranser
Små glapp uppstår p g a att toleransen i
Pro/E inte är exakt 0. T ex kan det förvalda
värdet (alltid på relativ tolerans) på 0.0012
påverka beräkningsmodellen negativt.
Det går inte att sätta toleranserna till exakt 0,
vilket kan orsaka små glapp i ANSYS. Vidare
vore det intressant att undersöka om hur
ANSYS påverkas av att ändra från relativ till
absolut tolerans.
1. Relativ tolerans. Toleransen är för alla
modeller förvald till 0.0012. Orsakar ofta
små glapp i ANSYS, men är inte
komplicerat och skapar små modeller.
2. Absolut tolerans. M h a denna tolerans kan
olika värden sättas och prövas för att se vilket
resultat dessa genererar. Orsakar dock tunga
och tröga modeller, men m h a detta kan man
undvika glapp ANSYS.
Bockningsradier
Närmare förklaring av skillnad mellan
relativ och absolut tolerans:
Exempel
Bockningsradier
Externa referenser
Pro/E modell
Resultat ANSYS (Sidoplåtarna kommer ej med pg.a. externa referenser):
Appendix D – Test protocol of comparison of STEP and Parasolid
format
Testprotokoll av jämförelse mellan STEP och Parasolid format
Test of ANSYS; Comparison of STEP and Parasolid format
DM = DesignModeler.
Parasolid license exist.
Stag:
Parasolid:
Step:
DM: The model is fine, 3 parts.
DM: The model is fine, 3 parts.
Steering anchor:
Parasolid:
Step:
DM: The model is fine, 24 parts.
DM: The model is fine, 24 parts.
Cab:
Parasolid:
DM: The model is not looking complete,
only 101 parts!
Step:
DM: The model is fine, 133 parts.
Power frame:
Double volumes
Missing parts
Parasolid: The model is not looking alright; double volumes and parts are missing. Totally
156 parts instead of 119 parts, which means there must be a lot of double
parts/volumes/errors.
Step: The model is fine in DM, 119 parts.
Appendix E – Checklist
Checklista
Appendix F – Guidelines for modelling in Pro/E
Riktlinjer med tips i Pro/E
Appendix G – Detailed information
Detaljerad information
Appendix G – Detailed information
TOLERANCES AND ACCURACY
Be aware that tolerances and accuracy settings in Pro/E can generate small gaps and problems in
ANSYS.
The small gaps are caused by the relative accuracy, which by default is set to 0.0012 (1). Test to
change it to absolute, which means that you can try different values to see if it solves the problems. It
can solve some of the problems/gaps in ANSYS.
The accuracy must be changed in one and each part; it can not be changed in the assembly – mode.
If possible; Create a mapkey to help changing the accuracy (see instructions “mapkeys”). This is
especially efficient if the procedure will be repeated for many models and parts.
N.B. Make sure that you don’t “check in” the model for analysis with absolute tolerance, it’s probably
huge! Decide in agreement with the Structural Analysists about how they will have access to the
model.
See next page for instructions to change relative accuracy to absolute.
The accuracy in ANSYS can also be changed, but only the measurement accuracy. There are three
options: High, Normal and Low. See instructions below:
For further information, see (1) and (2).
GEOMETRY CHECKS
Make sure that the model doesn’t have any Geometry Checks before you send it to analysis. You find
the Geometry Checks under “info”. The model is okay if “Geometry Checks” is grayed out and
unavailable. Otherwise open Geometry Checks and investigate the problem.
Some of the Geometry Checks are possible to remove through changing the relative accuracy to
absolute (see “tolerances and accuracy”) and test different values, although this shouldn’t be a default
method. Worth to mention is that Geometry Checks do not always cause problems.
See instructions below.
For further information, see (1).
To check if you have any Geometry Check, do as follows:
1. Info Geometry Checks
Figure 1. Geometry Checks instructions.
MAPKEYS
Is there any possibilities to create mapkeys for simplifying the transfer to ANSYS?
Please, contact the CAD support (31259) to know what mapkeys you are allowed to create.
Also, feel free to discuss with other Mechanical designers about what mapkeys they use and
recommend.
A mapkey is created to simplify a process, when a sequence of commands is frequently used (3).
See instructions for creating a mapkey below (3).
MODELLING
General modelling tips, worth thinking of before and while modelling:
• Sometimes it is better to create one big/single part and use Cutout functionality to cut out
pieces of it to create the final part. Think of when this would simplify the modelling and also
the analysis, in agreement with the Structural Analysist. It’s often better when you want to
avoid difficult corners and edges.
•
While using the Cutout functionality to copy geometries between models of different sizes in
Assembly mode, it is especially important to ensure that the accuracies are the same. (1)
•
If possible, create a single part rather than an assembly. You can create a single part out of
an assembly through the tool “merge” and by merging subassemblies together. This action is
only possible if there aren’t any assembly features.
If you have further questions or if you haven’t found the information you were looking
for, call the CAD support (31259) or search for more information at the help centre in
Pro/E or at the PTC Technical Support Knowledge Base at:
http://www.ptc.com/support/index.htm (You need a user account at www.ptc.com)
References and further information:
(1) “General Information Regarding Geometry Checks (Geom Checks)” on next page. To access
the original homepage, you need a user account at www.ptc.com.
Retrieved May 5, 2011 from: https://www.ptc.com/appserver/cs/view/solution.jsp?n=105892
(2) Search for “About changing part accuracy” at the help centre in Pro/E.
(3) “Suggested Technique for Creating Mapkeys and Adding to a Toolbar”. To access the original
homepage, you need a user account at www.ptc.com.
Retrieved May 4, 2011, from:
http://www.ptc.com/cs/cs_21/howto/fun453/fun453.htm
Figure 2. Where to find the help centre in Pro/E.