33RD YEAR OF MECHANICAL ENGINEERING UNDERGRADUATE STUDENT CONFERENCEMECH4501 Wednesday, 20 April 2016

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WELCOME

I warmly welcome you to our Annual Mechanical Engineering Undergraduate Student Conference in the School of Mechanical and Mining Engineering. We are looking forward to a range of presentations from all students in the School this year. The Mechanical Engineering Undergraduate Student Conference provides our undergraduate honours thesis cohort the opportunity to present their research to an audience of academics, their peers and engineering professionals. This is great experience for presenters and offers the opportunity to learn more about the extensive research undertaken across the School. This network is the next generation of engineers and so I encourage you to strengthen your links with your peers now as they could be your future colleagues, collaborators or leaders. This conference is unique and forms an important part of the training experience in the School, providing an opportunity for our students to supplement their technical and scientific training with essential transferable skills in communicating the impact of their studies and conversing with others. Our research community actively pursues excellence in research, promotes collaboration, fosters integrity, and encourages creativity and innovation and this is demonstrated today by our undergraduate students who showcase the high quality and broad range of expertise across our School. I am confident you will find this an engaging and beneficial experience.

Professor David Mee Head of School School of Mechanical and Mining Engineering

The University of Queensland

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CONTENTS

WELCOME ....................................................................................................... 1

MESSAGE FROM THE CONFERENCE COORDINATOR .............................. 2

SUMMARY OF CONFERENCE DUTIES ......................................................... 3

ORDER OF PROCEEDINGS ............................................................................ 4

SESSION TIMES .............................................................................................. 5

CONFERENCE PROGRAMME ........................................................................ 6

ABSTRACTS .................................................................................................... 8

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MESSAGE FROM THE CONFERENCE COORDINATOR

On April 20, 2016 you will communicate your ideas formally to a group of your colleagues and

you will receive useful feedback related to your thesis project. The programme follows the

form of a professional symposium, and you should dress and behave appropriately. There will

be many times throughout your career when you will be called upon to give presentations of

technical material. Make the most of this opportunity to develop your presentation skills and

help your colleagues to develop their skills by being constructively critical during the

discussion periods.

Each presentation will be formally assessed by everyone who attends. Please read through

the synopses before the talks as assessment includes these.

Attendance at all sessions is compulsory. Make sure you hand in your assessment sheets

to the Duty Officer as proof of attendance.

You need to check the schedule to see if you have special duties. A summary of the

Chairperson and Duty Officer roles is provided on page 2. An order of proceedings for each

session is also provided on page 3 to guide you through the session.

PRESENTATION PRIZE A small prize will be offered for the best presentation of the day. These will be selected by a

small panel of the academic staff, which will consider the quality of the synopsis and the

recommendation of the staff critic. This will be announced and presented at the closing

session.

YOUR ACTIVITES DURING THE CONFERENCE 1. A 15-minute presentation: 12 minutes presentation time and 3 minutes question time.

2. Attend all sessions during the day and evaluate the performance of the presenters using

the assessment sheet (one assessment sheet per session), submit your assessment

sheet to the session duty officer. You do not have to submit an assessment sheet if you

are one of the presenters in the session.

CONFERENCE VENUES Mansergh Shaw Building (45) Advanced Engineering Building (49)

Room 205 Room 601

Room 414

Professor David Mee

Conference Coordinator Mechanical Engineering Undergraduate Student Conference, 2016

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SUMMARY OF CONFERENCE DUTIES

CHAIRPERSON

The timing for all sessions is critical, to permit the audience to move between parallel sessions as they wish. Most sessions are made up of presentations which have related subject matter and a common theme. The Chairperson should:

1. Start each session with a summary of the generic topic and a brief description of how the work of each speaker relates to it.

2. For each speaker: a. Give a brief introduction to each speaker, b. Inform the speaker when there is one minute’s

presentation time remaining, c. Bring each presentation to a close at the

designated time (this may involve instructing the speaker that time is now complete),

d. Go to the front of the room and control questions during question time (be prepared with a question in case there are none from the audience or if there are only one or two questions and time remains).

3. Introduce the staff critic after all speakers have presented.

4. Thank the staff critic and all the presenters. 5. Remind audience to pass their assessment

sheets to the Duty Officer, and 6. Close the session.

Each Chairperson is responsible for the timing of presentations within their sessions, and must use the following timetable:

5 min - General session introduction by Chairperson

12 min - Speaker’s Presentation

3 min - Questions from the Audience

5 min - Staff Critic’s closing remarks

DUTY OFFICER

The role of the Duty Officer is to ensure that everything runs smoothly for the presenters.

The Duty Officer should:

1. Ensure that the room is prepared and that the scheduled staff critic is present,

2. For each speaker, a. Assist the speaker to locate their presentation

on the computer, b. During each presentation, try to help the

presenter or the chairperson when needed, c. Make sure the room is comfortable for the

occupants (lighting, noise, etc.) and try to solve any problems associated with the room,

d. Report to the conference coordinator if a problem is too difficult to resolve,

3. After the staff critic has presented and the chair has closed the session, collect the assessment forms, and,

4. Submit to the coordinator.

If you are Duty Officer for one of the last session of the day in your room, please pack up the computers, laser pointer, etc. and put everything in the computer bag and leave the bag on the front table.

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ORDER OF PROCEEDINGS

BEFORE THE START OF THE SESSION

The presenters report to the session chairperson The duty officer ensures that the room is prepared (presentation files are ready) and ensures that the scheduled staff critic is present.

DURING THE SESSION

Chairperson’s introduction (5 minutes) Announces the start of the session Self-introduction Introduces the duty officer Introduces the theme of the session Introduces scheduled speakers and their topics Introduces the staff critic Talks about time limits for each speaker (12 minutes + 3 minutes) Talks about the assessment sheet (everybody must complete the sheet and submit it to the duty officer, mentions the criteria) Calls the first presenter

Presenter One (12 minutes presentation + 3 minutes questions)

At 11 minutes the chairperson reminds the presenter At 12 minutes the chairperson asks the speaker to stop and calls for applause. The chairperson asks for questions from the audience. The chairperson identifies who has a question and handles the discussion. The chairperson asks the first question if none are forthcoming from the audience. At 15 minutes the chairperson closes the discussion and calls the next presenter (Everybody fills in the assessment sheet for the presentation)

Presenter Two onwards

Follow the same steps as above.

Last Presenter (12 minutes presentation + 3 minutes questions) At 11 minutes the chairperson reminds the presenter Chairperson calls for questions after the presentation At 15 minutes the Chairperson calls the staff critic for comments (Everybody fills the assessment sheet) Staff critic’s comments (5 minutes) Chairperson thanks everyone and concludes the session

AFTER THE SESSION

Everyone submits the assessment sheet to the duty officer and the duty officer hands the assessment sheets to the Conference Coordinator.

NOTES: Let us work together to make the conference a successful event. Chairpersons are requested to spend a little time before the conference to practice. They should speak loudly and effectively control the session (introduce speakers, invite questions, control time etc.).

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SESSION TIMES

Venue A

45-205

Venue B

45-414Venue C

49-601

14:00 – 14:05 Welcome by Professor David Mee (45-205)

14:05 – 14:15 Break

14:15 – 15:25

(4 speakers) A1: Thermofluids 1 B1: Materials C1: Dynamics 1

15:25 – 15:45 Afternoon Tea Break (outside ELCX)

15:45 – 16:55

(4 speakers) A2: Dynamics 2 B2: Manufacture C2: Thermofluids 2

16:55 – 17:05 Close (45-205)

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CONFERENCE PROGRAMME

Venue A – 45-205

A1: Thermofluids 1

Venue B – 45-414

B1: Materials

Venue 3 – 49-601

C1: Dynamics 1

Time Title Presenter Critic Chair Duty O Title Presenter Critic Chair Duty O Title Presenter Critic Chair Duty O

14:15 Chair’s Introduction

Ale

x K

lim

en

ko

La

ch

lan

Wh

yb

orn

Heath

er

Mu

ir

Chair’s Introduction

An

dre

j A

tren

s

Jam

es F

arr

ah

Kri

sti

an

Ju

el

Chair’s Introduction

David

Me

e

Hait

ha

n F

ari

d A

li A

l H

inai

Ju

liett

e L

ee

14:20

2.5-D Final Volume Flow Solver

Supervisor: Ingo Jahn Dan

iel

Hatc

h

Influence of hydrogen on advanced high strength steels (AHSS)

Supervisor: Andrej Atrens

Jeth

ro

Bla

nc

h Optimisation

Strategies for Bulldozer Pivot Push

Supervisor: Ross McAree

Sam

uel

Bett

en

s

14:35

Effects of Density and Bouyancy on Firewhirls

Supervisor: Alex Klimenko

Cia

ran

M

urp

hy

Remaining Life Prediction of Polyethylene Pipes in Service: A Literature Review of Existing Research

Supervisor: Rowan Truss

Yu

an

fen

g

Ch

en

Development of New Practical Class for METR4201 Introduction to Control Systems Supervisor: Ross McAree

Dyla

n

Bla

ck

14:50

Exergy analysis of liquefied natural gas (LNG)

Supervisor: Alex Klimenko A

bd

ulk

ari

m R

ad

wan

Determination of Remaining Life of Polyethylene Pipes

Supervisor: Rowan Truss M

ing

Su

m

Ho

Quantification of Noise Impacts on Mine Approval

Supervisor: David Mee

Willi

am

Garb

ett

15:05

Computational Fluid Dynamics of Turbulent Combustion: Opposed Flow

Supervisor: Alex Klimenko

Co

nn

or

S

tau

nto

n

Environmental Degradation of Aerospace Composites in Contact with Titanium and Aluminium

Supervisor: Andrej Atrens

Min

Kyo

ng

Kim

Analysis of Shaft Rotordynamics and Associated Bearings Designs for a Radial Inflow Turbine

Supervisor: Kamel Hooman

Sam

Gart

on

15:20 Staff Critic Staff Critic Staff Critic

Afternoon Tea Break (outside ELCX)

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Venue A – 45-205

A2: Dynamics 2

Venue B – 45-414

B2: Manufacture

Venue 3 – 49-601

C2: Thermofluids 2

Time Title Presenter Critic Chair Duty O Title Presenter Critic Chair Duty O Title Presenter Critic Chair Duty O

15:45 Chair’s Introduction

Bil

l D

an

iel

Dyla

n B

lack

Willi

am

Garb

et

Chair’s Introduction

Mic

ha

el H

eit

zm

an

n

Yu

an

fen

g C

he

n

Min

g S

um

Ho

Chair’s Introduction

Vin

cen

t W

he

atl

ey

Cia

ran

Mu

rph

y

Ab

du

lkari

m R

ad

wan

15:50

A Compatative Analysis of Baseline & Nonlinear Model Predictive Controllers for a Simple Robotic Manipulator

Supervisor: Michael Kearney

Jo

hn

P

an

izza

Springback in Chain-die Forming

Supervisor: Bill Daniel

Jack

Bra

ilsfo

rd Conjugate Heat

Transfer modelling of supercritical CO2 in a parallel channel using Eilmer3 Supervisor: Anand Veeraragavan

Jack

Ta

ylo

r

16:05

Electric cars evolution: will it happen or not? Supervisor: Alex Klimenko

Hait

ha

m

Fa

rid

Ali

Al

Hin

ai Feasibility study for

composite turbo compressor stage

Supervisor: Michael Heitzmann

Jam

es

Fa

rrah

Application of Boundary Conditions and Divergence Cleaning in the MHD Algorithm

Supervisor: Vincent Wheatley

La

ch

lan

Wh

yb

orn

16:20

Development of squat cracks in railways

Supervisor: Bill Daniel Bry

ce

Jeu

de

Literature Review: Corrosion of aluminium for ship building application

Supervisor: Andrej Atrens

Gu

rpre

et

Jag

pa

l

Implementation pf an Unstructured Mesh Generation Code for Eilmer 4

Supervisor: Peter Jacobs

Heath

er

Mu

ir

16:35

Cost-benefit analysis of installing door portals at the Domestic Terminal Building

Supervisor: Saiied Aminossadati

Ju

liett

e

Le

e

Development of an Interactive New Product Development Process

Supervisor: Michael Heitzmann

Kri

sti

an

Ju

el

16:50 Staff Critic Staff Critic Staff Critic

Close (45-205)

A1: Thermofluids 1

SYNOPSES

2.5-D Final Volume Flow Solver

Daniel H. Hatch

Shaft seals with carbon floating rings (CRS) are an alternative mechanical seal often used in turbomachinery.

CRS are generally installed in series to control leakage over multiple stages. The seals operate by constraining

the working fluid to a fine channel between the ring and the shaft. In between rings the working fluid expands

into comparatively large chambers. Seal leakage is a key factor in operating efficiencies of turbomachinery

and excess leakages can elevate maintenance costs. This seminar gives an overview of a numerical

investigation into super-critical CO2 flow through carbon floating ring seals.

Carbon floating rings are machined to provide a gap that is of the order of 100µm. The CRS problem

geometry was segmented into repeated channel to chamber sections by Eike Hylla et al (2015). Here

conventional 2D and 3D solvers require meshes with high resolution in the radial direction at the boundaries

as to resolve boundary layer effects. In order to ensure the overall quality of the mesh with respect to

smoothness and aspect ratios, standard solvers require a mesh with high resolutions in the axial and tangential

directions sustained over more substantial lengths. In order to reduce the size of the overall numerical

simulation, three approaches were investigated that make use of the problem specific geometry.

These approaches were implemented and assessed as quasi-one-dimensional and quasi-two- dimensional flow

solvers. Here the governing equations were limited to x, y and z-directional momentums per volume, density,

and total energy per volume as stated by P.A. Jacobs et all in the Eilmer3 Theory Guide (2012). The first

approach was to assume analytical approximations of the temperature and velocity profiles across the entire

operational gap as to remove the need for numerical spatial derivatives of component velocities and

temperatures in the radial direction. This gave reasonable approximations of shear stresses at the walls yet

failed to describe boundary layer growth resulting in choking of transonic and supersonic flow. Following

this, spectral methods were patched over a three to five layers of cells in the radial direction to analytically

describe wall stresses and internal viscous phenomena, namely choking. The third approach was centred on

the integration of empirical relationships that absolved the need for numerical derivatives of flow properties in

the radial direction. The accuracy of the experimentally based simulations is partly undermined by the smooth

wall assumption in the calculations of friction factors and the general applicability of experimental

relationships.

BIBLIOGRAPHY

Eike Hylla, M. S. (2015). Investigations on Transonic Flow of Super-Critical Co2.

Proceedings of ASME Turbo Expo 2015: Turbine Technical Conference and Exposition (pp. 1-12). Montréal:

MAN Diesel & Turbo SE

P.A. Jacobs, R.J.-R. (2012) Eilmer’s Theory Book: Basic Models for Gas Dynamics and Thermochemistry.

Brisbane: Faculty of Engineering, Architecture and Information Technology.

Effects of Density and Buoyancy on Firewhirls

Ciaran J Murphy

Fire whirls – sometimes referred to as fire tornadoes – are dangerous fire induced whirlwinds which have the

capability to cause catastrophic damage. Due to their erratic spread and movement, increase of fire intensity

and wind damage, fire whirls pose a significate safety threat to anyone in their path. Further understanding of

how fire whirls act is essential for predicting their movement and improving firefighting techniques. Fire

whirls have had catastrophic consequences in the past. One of the first recorded fire whirls – and the deadliest

– occurred in Japan in September 1923. Following the Great Kanto Earthquake just south of Tokyo a massive

fire whirl reportedly killed 38,000 people (Kuwanaa, Sekimotob et al. 2007).

In 2011, Chuah et al showed that the length of non-rotating buoyant flames closely matched the classical

Burke-Schumann formula for predicting flame lengths. This solution however underestimates the length in a

rotating flow, especially those with low Rossby numbers. More recent work produced by Klimenko and

Williams (2013) has improved the formula for rotating flame by using the strong vortex approximation and

vortex compensating regime. Their approach closely matches experimental results however the model does

not incorporate changing gas density. In reality as gas burns its density undergoes substantial change.

Dowd (2013) and Kamitsis (2015) have undertaken work to determine whether density changes exert

additional influence on the flame height and investigated the effects of the changing buoyancy upon the flow.

Through the use computational fluid dynamics (CFDs) they were able to simulate a range of situations

involving different models for both density and buoyance. Their results support the theory of the strong vortex

approximation and vortex compensating regime proposed by Klimenjo and Williams (2013).

This thesis will continue the work of Dowd (2013) and Kamitsis (2015) by investigating the effects of

modelling fire whirls using tangential velocity at the boundary conditions instead of a Coriolis force term. The

Coriolis effect used in prior work effectively rotated the reference frame which was being modelled. The

addition of tangential velocity at the boundary conditions differs by adding a rotation to the air around centre

of the model. Although a subtle difference it is predicted this will cause a delay in the fire whirl formation.

Current results are inconclusive as to the impact this has on the length of the fire whirls.

BIBLIOGRAPHY

Chuah, K. H., Kuwana, K., Saito, K., and Williams, F. A. (2011). Inclined fire whirls. Proceedings of the

Combustion Institude, 33(2):2417-2424

Dowd, C. (2013). The effects of Density Changes in fire whirls. Brisbane: The University of Queensland

Kamitsis, A. (2015). The CFD Simulation of Fire Whirls. Brisbane: The University of Queensland

Klimenko, A. Y. and Williams, F. (2013). On the flame length in firewhirls with strong vorticity. Combustion

and Flame, 160(2):335 – 339

Kuwana, K., Sekimoto, K., Saito, K., Williams, F. A., Hayashi, Y., and Masuda, H. (2007). Can we predict

the occurrence of extreme fire whirls? AIAA JOURNAL, 45(1):16-19

Exergy Analysis of Liquefied Natural Gas

Abdulkarim A. Radwan

Natural gases are extremely important energy source, several daily applications are integrated from natural

gases across the world. it is being used in residential, industrial and commercial sectors such as heating,

manufacturing, generating electricity and even cooking source. However, the transportation of natural gases

involves the two main processes. Transforming its gas state to liquid state in order to minimize its volume,

before transportation. after that work will be generated to vaporize the liquid into gas again. The major benefit

of this process is the ease of transportation of natural gases to overseas or locally by pipelines- over short

distances. Cuff and Goudie (2009) stated that the process of condensing the natural gas into liquid state will

shrink the volume of the system by 1/600 of that in the gas state, which is similar to decrease the size of a

basketball to the size of a ping-pong.

This liquefying process is now the main technique of transportation of natural gasses however, aside form its

benefits this process will dissipate small amount exergy during the phase transformation, in both the

liquefaction and the regasification processes. At hundred percent efficiency, the liquefaction process will most

likely to take ten percent of energy during phase change from liquid to gas. On the other hand, regasification

process will also take two percent of energy in order to vaporize the system again (Hrastar, 2014).

Would it be economically effective to find a slightly efficient method of exergy analysis during liquefaction

and regasification processes. The exergy analysis of the liquefied natural gas containing computing the

maximum available energy of the LNG. That represents the energy which achieved when LNG reaches

equilibrium, in thermodynamics it’s the measure of reaching the atmospheric pressure and temperature. A

studied for the purpose of identifying the higher availability of the system will be compared with the

economical cost of the liquefaction, regasification and transportation processes.

BIBLIOGRAPHY

Cuff, D. and Goudie, A. 2009. The Oxford companion to global change. New York: Oxford

University Press, p.452.

Hrastar, J. 2014, Liquid natural gas in the United States. North Carolina: MacFarland & Company,

Inc.

Computational Fluid Dynamics of Turbulent Combustion

Connor W. Staunton

This project aims to use Computational Fluid Dynamics (CFD) to compare turbulence models for the case of

non-premixed Hydrogen combustion. Large Eddy Simulation (LES) and Reynolds Averaged Navier Stokes

(RANS) turbulence models are compared and the qualities of each discussed and analysed. Non-premixed

combustion is common to many practical applications of combustion and this motivates the study. By

comparing the accuracy of LES and RANS models against existing experimental data the ideal applications of

each model can be further defined.

Computational Fluid Dynamics (CFD) allows numerical approximations to be developed to simulate fluid

flow phenomena by using governing equations of fluid flow. The increasing computing power allows CFD

simulations to run at increased speeds, for complex geometries and with higher fidelity, making design

applications more feasible and common.

OpenFOAM (Open Field Operation and Manipulation) is the CFD package chosen to develop simulations.

OpenFOAM is a free, easily accessible open source CFD software package. OpenFOAM has a large user base

across many fields of engineering and science, within both commercial and academic organisations.

RANS techniques solve for the mean values of all quantities. Balance equations for Reynolds averaged

quantities are gained by averaging the instantaneous balance equations. The solution of these equations

provides averaged quantities averaged over time. Given that RANS only produces averaged quantities it

doesn’t describe small variations in the flow and doesn’t accurately depict small scale turbulence.

Large Eddy Simulation (LES) is a numerical technique for integrating spatially filtered equations of motion

describing high-Reynolds number time-evolving, three dimensional turbulence (Moeng &Sullivan 2002). LES

is the middle ground between brute force Direct Numerical Simulation (DNS) and less accurate computational

turbulence models such as RANS, incorporating elements of both approaches(Poinsot & Veynante 2001).

DNS is far too computationally expensive for use in this project.

With a more precise case particular comparison of LES and RANS techniques selection of either technique

can be quantitatively justified making further promoting practical applications of either technique..

BIBLIOGRAPHY

Moeng, Chin-Hoh, and PP Sullivan. "Large eddy simulation." Encyclopedia of Atmospheric Sciences 1140

(2002): 1150.

Poinsot, T., & Veynante, D. (2001). Theoretical and Numerical Combustion. Philadelphia: R.T. Edwards.

Turns, S. R. (2006). An Introduction to Combustion: Concepts and Applications. Singapore: McGraw Hill.

B1: Materials

SYNOPSES

Influence of Hydrogen on Advanced High Strength Steels

Jethro Blanch

Advanced high strength steels are considered to be a favourable material in the development of safe and

lightweight cars. This is due to extremely high yield strengths despite still maintaining a density of

approximately 7.8g/cm3. However, it is well known that steels with tensile strengths over 1000MPa are highly

susceptible to hydrogen embrittlement. (Robertson et al. 2014)

In the industry, there is no definitive mechanism through which hydrogen embrittlement occurs. Today there

are two generally accepted explanations for hydrogen embrittlement in carbon steels, these are: hydrogen-

enhanced decohesion and the hydrogen-enhanced localized plasticity mechanism. (Robertson et al. 2014)

Academic work in this field provides evidence that the factors that increase hydrogen embrittlement are as

follows: a higher tensile strength (although this trend only exists above tensile strengths of 1000MPa)

(Robertson et al. 2014), an increased amount of hydrogen in the surrounding environment, and decreased

strain rates. (Venezuela et al. 2015)

Testing has been developed using linearly increased stress tests and two different martensitic advanced high

strength steels. These are MS1300 and MS1500, designating a tensile strength of at least 1300 and 1500

respectively. The steels will be immersed in a solution of 3.5% NaCl. Hydrogen content in the surrounding

environment will be varied by modifying pH. The linearly increased stress tests are not conventional

compared to constant extension rate tests. However, linearly increased stress tests have been proven to

produce faster tests at the same induced stress rate due to rapid failure after plastic deformation (Winzer et al.

2008). This is useful as it leads to a cleaner fracture surface with less corrosion from the surrounding solution.

From the results, the effect of each individual variable will be investigated, as well as how it contributes to the

overall hydrogen susceptibility. The susceptibility will be quantified using the hydrogen susceptibility and

embrittlement indexes, relating the yield strength and ductility before and after the exposure to the hydrogen

environment. Fractography will support these findings, providing evidence from the fracture surface. The

results expected are that:

• A lower pH will reduce the overall ductility and tensile strength of the specimen

• Increased tensile strength will increase hydrogen susceptibility

• Increasing the rate of stress will decrease the hydrogen susceptibility

• The predominant mechanism of hydrogen embrittlement will be found.

BIBLIOGRAPHY

Robertson, I. M., Sofronis, P., Nagao, A., Martin, M. L., Wang, S., Gross, D. W., & Nygren, K. E. (2015).

Hydrogen embrittlement understood. Metallurgical and Materials Transactions A, 46(6), 2323-2341.

doi:10.1007/s11661-015-2836-1

Winzer, N., Atrens, A., Dietzel, W., Song, G., & Kainer, K. U. (2008). Comparison of the linearly increasing

stress test and the constant extension rate test in the evaluation of transgranular stress corrosion cracking of

magnesium. Materials Science & Engineering A, 472(1), 97-106. doi:10.1016/j.msea.2007.03.021

Venezuela, J., Liu, Q., Zhang, M., Zhou, Q., & Atrens, A. (2015). The influence of hydrogen on the

mechanical and fracture properties of some martensitic advanced high strength steels studied using the

linearly increasing stress test. Corrosion Science, doi:10.1016/j.corsci.2015.06.038

Remaining Life Prediction of Polyethylene Pipes in Service

Yuanfeng Chen

Polyethylene has been the material of choice for many piping applications for decades. It has been preferred

over traditional material like steel due to light weight and good corrosion resistance. Safety of PE pipe

application in Australia and globally is ensured by: 1) Standardised manufacturing requirements, including

requirements of Oxidation Induction Time (OIT), Maximum Allowable Operating Pressure (MAOP) and

Standard Dimension Ratio (SDR); 2) Guidelines with regard to handling, storage, installation and fittings. PE

pipes are conventionally designed to have a lifetime of 50 years, however, it is logically expected that the

actual lifetime of a proper PE pipe system can be more than 100 years (StandardsAustralian, 2009). For

economic efficiency, accurately designed safety assurance is need to maximise the extension of design

lifetime betwwen 50 to 100 years. The focus of present study is to review useful information in the literature

and propose a practical methodology of remaining life evaluation that is field practical. With comprehensive

guidelines enforeced, it is safe to assume that short-term failure of PE pipes can be avoided. On the other

hand, where complete avoidance is not possible, long-term failure modes of PE pipes can be summarised as 1)

Depletion of antioxidant resulting in rapid degradation of material (Dear, 2009); 2) Slow Crack Growth (R.

Lang, 1997; R. Lang, 2009; A. Gray, 1981). For deplection of antioxidant failure, standards are available to

properly test OIT (ASTM, 2008j); together with Arrhenius theory, failure time can be tested in relatively short

time frame and extrapolated (R.K. Rowe, 2010). The challenge of accurate prediction becomes proper

sampling. For slow crack growth, vast number of methodologies have been proposed in the past decade (G.

Pinter, 2007; DIN-EN-ISO, 2012); however, the challenge remains the difficulty of small crack detection on

PE pipes..

BIBLIOGRAPHY

A. Gray, J. M. J. P., 1981. Fracture behaviour of polyethylene pipes. Plastics and Rubber Processing and

Applications, 1(51).

Anon., 2008j. Standard test method for oxidative-induction time of polylefins by differential scanning

calorimetry. s.l.: ASTM.

ASTM, 2008j. Standard test method for oxidative-induction time of polyefins by differential scanning

calorimetry. s.l.: s.n.

Dear, J. S. M. S. H. B. J., 2009. Methods for determining the in-service life of polymer water pipes. J Mater

Science, Volume 44, pp. 4683-4691.

DIN-EN-ISO, 2012. Plastics piping and ducting systems - Determination of the long-term hydrostatic strength

of thermoplastics materials in pipe form by extraplation. s.l.: s.n.

G. Pinter, M. H. R. l., 2007. Lifetime and safety assessment of PE pressure pipes based on fracture mechanics

fatigue tests. ANTEC.

R. Lang, A. F. G. P., 2009. Prediction of the remaining lifetime of polyethylene pipes after up to 30 years in

use. Polymer Testing, Volume 28, pp. 737-745.

R. Lang, A. S. G. D., 1997. Applicability and Limitations of Current Lifetime Prediction Models for

Thermoplastics Pipes Under Internal Pressure. Die Angewandte Makromoledulare Chmie, 247(4429), pp.

131-145.

R.K. Rowe, M. I. R. B. D. A. A. E., 2010. Antioxidant deplection from a high density polyethylene

geomembrane under simulated landfill conditions. Journal of Geotechnical and Geoenvironmental

Engineering, Volume 136, pp. 930-939.

StandardsAustralian, 2009. AS/NZS 4130:2009 - Polyethylene (PE) pipes for pressure applications. s.l.: s.n.

Determination of Remaining Life of Polyethylene Pipes

Ming Sum Ho

The aim of the project is to develop rapid test methodologies to reasonably predict the remaining life of an in-

service high-density polyethylene pipe via direct measurements. Polyethylene (PE) is a mature, well

established pipe system that has been used in Australia in the oil and gas industry. To satisfy the current

version of Code of Practise – Upstream PE Gathering Networks for the Coal Seam Gas industry; which

require ‘the remaining lifetime of the existing pipeline to be assessed at a regular interview’, a practical pipe

sampling based methodology is to be developed.

Different operating conditions may have considerable differences in remaining life of the resin. This means

that the pipeline closer to the well (which expose to hotter environment) will require replacement while the

ones further down the pipeline may be fit for purpose for the remaining life of the project. Therefore, being

able to determine the remaining lifetime of a resin across different temperatures will provide substantial cost

benefits in the later life of CSG networks.

In this year-long project, 150 cylindrical samples are extruded from Qenos HDF193B Resin pipe which was

supplied by Santos Ltd. They will be divided into 4 batches. The first batch will not be under thermal aging

process; the second batch will be exposed to thermal aging process for 20 days; the third batch will be

exposed for 40 days and the last batch will be exposed for 60 days. These four batches of samples will be

fatigue tested using Instron machine, in order to determine the time at which brittle failure occur. The

literature will be referred throughout the testing of the first batch of sample to ensure similar experiment result

is obtained for the un-thermal aged samples (Haager, M & Pinter, G & Lang, RW 2006). It is expected that

the lifetime reduction depends on the time exposed to thermal aging. Thus, the remaining lifetime of the resin

under different operating conditions could be extrapolated using these results.

Nevertheless, oxidative induction time and Fourier transform infrared spectroscopy will be used to correlate

the consumption of the chemical additives to the resulting mechanical performances.

BIBLIOGRAPHY

Australian Pipeline Industry Association 2014, Upstream PE gathering networks – CSG Industry version 3.0,

APIA Code of Practice, Australia.

Haager, M & Pinter, G & Lang, RW 2006, ‘Ranking of PE-HD pipe grades by fatigue crack growth

performance’, Plastic Pipes, vol. 1, pp. 1-11.

International Organisation for Standardisation 2012, Polyethylene pipes – resistance to slow crack growth –

strain hardening test method, International Organisation for Standardisation.

Environmental Degradation of Aerospace Composites in Contact with

Aluminium and Titanium

Min K. Kim

Over the past century, composite materials have gradually become a lighter alternative to many of the steels

and aluminium-based alloys which were used in the structural parts of aircraft. The thesis presents research

findings to investigate the occurrence of galvanic corrosion between aluminium and titanium metals with

carbon fibre reinforced polymer (CFRP) composites in the structural applications of civilian aircraft. Such

problems may arise when CFRP panels, skins, spars and stiffeners are joined with aluminium fasteners.

Failure induced by galvanic action between aluminium and CFRP must be prevented in order to minimise the

loss of resources and human life.

The paper reviews literature about galvanic corrosion in CFRP and aluminium. The governing principles of

galvanic corrosion from textbooks were compared to the observations from experimental studies to investigate

the occurrence of CFRP forming a galvanic cell with aluminium. Experiments verified that the large potential

difference between aluminium and graphite fibres were accelerated the corrosion rate of aluminium and

caused delamination of the graphite composite (Tucker et al., 1990; Sloan et al., 1992; Alias et al., 1992).

Titanium was not reactive. Galvanic corrosion of CFRP-aluminium joints in aircraft may lead to physical

degradation of the fastener as well as the composite and therefore corrosion mitigation is a critical aspect of

aircraft manufacture.

Reviewed experiments were conducted in seawater, alkaline solutions and chloride solutions. However, the

seawater surroundings of the test are not accurate representations of the environment that aircraft components

are exposed to and therefore, the corrosion rates observed in the laboratory studies may be much greater than

the actual corrosion rates. High humidity, elevated temperature and increased oxygen concentration result in

acceleration of the corrosion process, as well as chlorides present in the atmosphere. Many airports are located

near the ocean and thus the higher relative humidity and chlorides in the atmosphere may provide an

environment for galvanic cells to form.

The paper looks at various methods for preventing galvanic corrosion from occurring in CFRP- aluminium

joints. Aluminium fasteners are inexpensive and lightweight, whereas aerospace fasteners are made from

titanium alloys and stainless steels which are heavier and more expensive than aluminium. On the other hand,

installation of sealants and application of coatings to aluminium fasteners will also add to costs and weight

and therefore, the research aims to conclude the optimal solutions depending on the joint conditions, such as

loading and joint configuration.

BIBLIOGRAPHY

Alias, M. N., & Brown, R. (1992). Damage to Composites From Electrochemical Processes. Corrosion, 48(5),

373-378.

Sloan, F. E., & Talbot, J. B. (1992). Corrosion of Graphite-Fiber-Reinforced Composites I Galvanic Coupling

Damage. Corrosion, 48(10).

Tucker, W. C., Brown, R., & Russell, L. (1990). Corrosion Between a Graphite/Polymer Composite and

Metals. Journal of Composite Materials, 24(1), 92-102

C1: Dynamics 1

SYNOPSES

Optimisation Strategies for Bulldozer Pivot Push

Samuel Bettens

Bulldozer pivot push is a method of bulk material movement used in coal strip-mining. After blasting, the

pivot push is performed by bulldozers to remove overburden or interburdens to expose the coal seams. The

dozer push is a cost-effective option for shallow coal seams (less than 40 m) and short transport distances (less

than 150m) compared to traditional excavator load and haul techniques (Darling, 2011). This thesis is

examining productivity measures and optimal strategies for performing this task. Ultimately, this work is

contributing to a larger project to automate bulldozer pivot push operations and achieve a productivity

superior to that of a human operator.

Initially, an analytical approach was considered for developing the optimal operation strategies. However, due

to the complexity of the problem, it was deemed that an empirical approach was required. This would involve

using experimentally determined cost models to assist in simulator-based optimisation of the pivot push. This

thesis uses the data from an experiment trialling three different pivot push designs at Wilpinjong coal mine in

central-west New South Wales. An application written in C++ was developed collaboratively to process the

data from the experiment.

As part of the bulldozer automation project, a bulldozer simulator modelling material flow was developed.

This was used to model the material movement of the dozer when processing the data. A force model of the

dozer is under development to allow the simulator to determine the maximum feasible blade loads based on

terrain geometry. The field data was used to assist in developing preliminary costing models of the dozer’s

operations for use with the simulator. This will be used to compare the costs of different dozer pivot push

designs produced by heuristics to optimise the pivot push process

BIBLIOGRAPHY

Darling, P. 2011, SME Mining Engineering Handbook, Vol. 3, Society for Mining, Metallurgy & Exploration,

Englewood, Colorado.

Development of new practical class for METR4201 Introduction to Control

Systems

Dylan J. Black

Control Systems design is a requisite skill for Mechanical Engineering and Mechatronics Engineering

graduates at The University of Queensland. METR4201 Introduction to Control Engineering is completed in

the third or fourth year of undergraduate study and draws extensively on students’ prior knowledge from all

years, and many seemingly disparate areas of study.

Current practical class arrangements within METR4201 succeed in meeting course learning objectives, but do

not demonstrate the broad applicability of the Control Engineering concepts covered in the course. A practical

class involving a Rotary Inverted Pendulum, otherwise known as a Furuta Pendulum (Cazzolato & Prime

2011), has been developed. The associated Thesis identifies the process for developing the practical class and

provides a critical analysis of the learning outcomes.

The Rotary Inverted Pendulum is a highly non-linear, open-loop unstable and non-minimum phase dynamical

system. The Rotary Inverted Pendulum has similar system dynamics to that of a pendulum on a cart, and

together these two systems form a benchmark for the development of control strategies (Cazzolato & Prime

2011).

The practical class and associated pre-work must be integrated into a tight learning schedule. The new

practical incorporates almost every concept covered in METR4201. Without due care, the problem as set for

students could be overwhelming and lead to poor outcomes. As such, appropriate guidance will be provided to

students, and the practical, whilst challenging, is designed to be rewarding.

Many resources will be provided to students including partial solutions to system modelling, non-linear

simulation tools and Simulink control implementations for the practical class itself. The Inverted Pendulum

rigs represent a significant investment by The University of Queensland. State-flow will be implemented

within the Simulink control implementations to ensure that if the pendulum is not successfully controlled by

the students’ controllers, a state-feedback controller designed as part of the associated Thesis work will catch

the pendulum. If this secondary control strategy fails, the system will shut off to prevent the apparatus from

damaging itself.

The final decision on the nature of the practical class belongs to Professor Ross McAree. The goal of this

thesis is to provide a student perspective on the practical and to assist with informing how to best utilize the

new practical equipment.

BIBLIOGRAPHY

Cazzolato, B S & Prime, Z 2011, ‘On the dynamics of the furuta pendulum.’, Journal of Control Science and

Engineering, 2011:1 –8, 2011

Quantification of Noise Impacts for Mine Approval

William Garbett

During the mine approval process the Environmental Noise Policy of the QLD government typically results in

a Leq(15 minute) noise criteria in the order of 35 to 40 dB(A) at the nearest private residences. As a

consequence, mines undertake noise measurements and modelling to show compliance. Accurately

interpreting such measurements can be difficult given the large distances between source and receiver.

This presentation details an analysis of high resolution data collected at long range > 2km from an open cut

mine. The dataset includes 1/3 octaves between 6.3 Hz - 20 kHz sampled every second; including

corresponding wind speed and direction. The object of this exercise was; to provide guidance for the statistical

contribution of mine noise in long range measurement; to develop a possible statistical method of eliminating

extraneous noise.

Considerations were made to delineate between day and night operation; day time noise was analysed

however due to the social impact night time noise is of primary interest to the investigation. To determine the

statistical contribution of mine noise comparisons were made between 6 pm and 6 am, high noise LAeq(30

seconds) > 35dB(A) and low noise LAeq(30 seconds) < 35 dB(A) spectra. Over months and two sites this data

identified spectral differences suggesting that common frequencies are dominant in causing criteria

exceedance. The same test was repeated for data modified using a low pass filter from 630 Hz; low pass

filtering is a common method for removing extraneous high frequency noise. The low pass filtered data can be

considered a more accurate reflection of mine noise with spectral differences likely to be caused by mine

operation. Initial results show a significant difference between the spectral content of high noise and low noise

periods with high noise being driven by 2 to 3 kHz frequencies and low noise driven by 31.5 Hz to 125 Hz

frequencies

Analysis of Shaft Rotordynamics and Associated Bearings Designs for a

Radial Inflow Turbine

Sam C. Garton

The Queensland Geothermal Energy Centre of Excellence (GGECE) is a research centre within the University

of Queensland (UQ) that has recently developed a refrigerant-based 7 kW radial inflow turbine. Test results of

the 7 kW turbine, which is currently set up at the Pinjarra Hills test facility, is being used to aid the design of a

supercritical CO2 100 kW radial inflow turbine. While there has been extensive research and development

into certain aspects of the turbine such as aerodynamic design, sealing and lubrication methods, the QGECE

would like a more comprehensive study into the rotordynamics of their system. As such, the aim of this thesis

is to experimentally measure shaft vibrations of QGECE’s 7kW radial inflow turbine, compare it to the

current rotordynamics model, and create an improved model from which recommendations can be made to aid

in the design of the QGECE’s 100 kW radial inflow turbine.

Rotordynamics, which looks at how a rotating shaft vibrates and the factors that affect vibration (namely shaft

and bearing stiffness), is a key aspect for the stable operation of a turbine. When the natural frequencies

coincide with the excitation frequencies (forcing unbalance at rotor spin speed), the spin speeds are referred to

as ‘critical speeds’. At critical speeds, the rotor system may be in a state of resonance, thus it is important to

avoid operating close to these speeds (Chen & Gunter, 2007).

The current rotordynamic model of the 7 kW turbine, generated by the QGECE (2015) using rotordynamics

analysis software XLRotor, indicates critical speeds of the first two modes around 25,300 RPM, with the third

and fourth modes around 25,900 RPM and 32,200 RPM respectively. Models created using ANSYS indicate a

much lower critical speed of the first and second modes, around 17,800 RPM using 2D elements and 22,200

RPM using 3D elements. Both the 2D and 3D models provide comparable third and fourth mode critical

speeds to that of the XLRotor model. Preliminary testing up to 11,750 RPM has shown increasing vibration

amplitude with increasing spin speed, but not to levels of that which would be considered a critical speed, as

expected. Further testing up to the operational speed of 30,000 RPM has been delayed due to an ongoing

operational issue. An initial model of the 100 kW turbine has been created in the meantime.

Further testing up to the design speed of the 7 kW turbine is expected to take place, pending the operational

issue. Experimental results will aid in the adjustment and refinement of the 7kW model, from which, the

100kW model will be improved accordingly and design recommendations can be provided to the QGECE.

BIBLIOGRAPHY

Chen, W. J., & Gunter, E. J. (2007). Introduction to Dynamics of Rotor-Bearing Systems. Victoria: Eigen

Technologies.

QGECE (RusselL, H. (2015). Rotordynamic Analysis of QGECE20_00. Brisbane: QGECE.

A2: Dynamics 2

SYNOPSES

A Comparative Analysis of Baseline & Nonlinear Model Predictive Controllers

for a Simple Robotic Manipulator

John F. Panizza

Thanks largely to increases in computational speed the field of automation and control engineering now has

the possibility of applying online model-based control schemes. Historically the application of model

predictive control (MPC) was restricted to systems with low update rates, primarily petrochemical processes,

though it is now seeing use within electronics and robotics due to its capacity to handle multi-input, multi-

output (MIMO) systems with imposed constraints. The examination of different control schema upon a simple

two-link revolute (RR) planar manipulator provides sufficient complexity to necessitate the use of NMPC

without being restrictive in simulation timing. Robotic manipulators are, of course, ubiquitous within industry

and thus any meaningful results will have broad implications.

Broadly, a simple manipulator model has been developed and implemented within MATLAB to allow for

controller comparisons. Initially, given a trajectory, an iterative linearised state feedback controller and a

feedback linearisation controller were tuned and implemented to provide a comparative base as research into

model predictive control was undertaken. When comparing to nonlinear model predictive controllers there are

a number of methodologies which can be used in solving the nonlinear optimal control problem with varying

horizon lengths, and, as such, the ACADO toolbox’s MATLAB interface (Houska et al. 2011) has been used

to compare controller performance with varying parameters and algorithms. The optimal control problems

relevant to the manipulator problem being minimum energy and minimum time (given actuator constraints)

optimisations. Results for the use of NMPC over baseline controllers are promising particularly when

unmodelled disturbances are introduced.

As an extension to the controllers at hand current efforts focus on the implementation of the aforementioned

NMPC solvers to include obstacle avoidance. Kearney, Siegrist, & McAree (2006) presented a control schema

featuring an avoidance filter to prevent tele-operated manipulators from colliding with known obstacles. At

this stage investigation is being undertaken to interface ACADO with the mixed-integer programming (MIP)

capabilities of Gurobi and YALMIP to create a combined iterative approach of optimal collision-free

trajectory generation and control.

BIBLIOGRAPHY

Kearney, M., Siegrist, P., & McAree, P. 2006, Constrained Model Predictive Control for Obstacle Avoidance

in Rate-Controlled Systems, Australian Mining Technology Conference.

Houska, B., Ferreau, H., Vukov, M., Quirynen, R., & Leuven, K. 2011, ACADO Toolkit – An Open Source

Framework for Automatic Control and Dynamic Optimisation, KU Leuven, Leuven.

Electric Car Evolution: will it happen or not?

Haitham Farid Ali Al Hinai

The history of the electric car began in the mid 19th century with the first documented model car in 1828 by

Hungarian inventor Anoys Hedlik. Fast Forward 180 years later and the electric vehicle still yet to overcome

the inefficient internal combustion engine pioneered in 1879. This is bound to change as demand for EVs is

rapidly increasing as more than half a million car was delivered to customers in 2015 (Ayre, 2016). Market

share of new EVs have have been increasing globally, with Norway leading at 12% followed by Netherlands

at 4% (International Energy Agency, 2015). However, this is not the case everywhere, EVs have substantial

increase in sales in some markets while other markets seem to reject this technology.

In order to solve the mystery of this phenomena certain aspects are to be reviewed beforehand. Firstly, the

Electric Petrol car. EVs are 70% different from petrol powered cars. They have only one mechanical moving

part, the shaft, which requires little to no maintenance. Furthermore, EVs are easier and cheaper to maintain

and more efficient than petrol powered cars and can travel twice the distance of petrol engines at the same cost

of fuel, which is very appeling to their owners. According to a study conducted on owners of EVs, most have

presented confidence in their cars (Bessenbach & Wallrapp, 2013). On the down side, they also commented

that going on long trip requires adequate prior planning. Thus, practicality of EVs is to be questioned. Also,

the need for sufficient infrastructure for EV owners and potential buyers is constraining EVs from widely

spreading.

Oil prices is a direct factor influencing the acceptability of EVs among buyers. According to an article by

Bloomberg, EVs will have a cumulative market share of 35% by the year 2040 and by the year 2020 EVs

would cost the same as internal combustion engine vehicles (Randall, 2016). The numbers seem high and

appealing, however, OPEC only predicts that EV market share will only reach 1% by the year 2040. Giants

such as Google, Apple and Tesla have spent a large amount of resources on plug-in cars predicting that EVs

are the future of locomotives. Nevertheless, with oil prices plummeting, more drivers choose to ride their

petrol cars for longer causing EVs short battery life to appeal unattractive. There is more than one scenario to

this dilemma of oil prices versus EVs. In order to solve it, analysing the past of engines to predict the future.

The movement from steam to gasoline engine in the railway industry is a historical event which will aid in

understanding the technological cycle of engines. Answering why and when it occurred will help in predicting

the long waited Electric Vehicle future..

BIBLIOGRAPHY

Ayre, J. (2016, March 8th). Retrieved April 1st, 2016, from Clean Technica :

http://cleantechnica.com/2016/03/08/global-electric-car-sales-surpasses-half-a-million-in-2015/

Bessenbach, N., & Wallrapp, S. (2013). Why do Consumers resist buying Electric Vehicles? Retrieved

August 2015, from

http://studenttheses.cbs.dk/bitstream/handle/10417/4329/nadine_bessenbach_og_sebastian_wallrapp.pdf

International Energy Agency. (2015). Global EV Outlook . Retrieved April 2nd, 2016, from International

Energy Agency: http://www.iea.org/evi/Global-EV-Outlook-2015-Update_1page.pdf

Randall, T. (2016, Feb. 25th). Here’s How Electric Cars Will Cause the Next Oil Crisis. Retrieved March 2nd,

2016, from Bloomberg: http://www.bloomberg.com/features/2016-ev-oil-crisis

Development of Squat Cracks in Railways

Bryce Jeude

A squat crack is a type of defect that originates in railway tracks due to interaction with the wheel of vehicles

that transverse the tracks, and was therefore classed as a rolling contact fatigue defect. They were first

discovered in Australia during the 1990’s and were characterized by the appearance that it leaves in the

railway track; a saddle shape. This shape is generated from a sub-surface crack growing in the rail which

allows material above it to flow plastically leaving a depression in the surface. Squat crack growth can cause

several problems in railway systems. Firstly, the most predominant issue is if the crack grows downwards into

the web which can result in complete rail fracture. The depression may also interact with wheel impact

loadings causing advanced deterioration. Lastly, a known counter-measure to the growth of the squat crack is

rail grinding, which removes the top layer of the rail, however this is an expensive option and decreases the

rail track life.

A finite element model of the scenario was created in ANSYS, where the geometry of the railway track, the

wheel, and the squat crack were all defined according to background literature and standards. The model also

included relevant parameters such as the contacting surfaces, the pre-meshed crack, plus loads and supporting

surfaces. Of the three crack sizes that were initially modelled in the first semester (small, medium and large),

with the wheel placed in the centre of the rail, the small crack was found to have the most severe equivalent

stress intensity factor, combination of the three crack modes, which exceeded the other crack sizes.

Investigation into an even larger crack size confirmed the trend previously hypothesized, that the equivalent

stress intensity factor on average decreased in magnitude.

The dynamic component of the system is considered by modelling the wheel in two different locations:

centred over the middle of the squat crack, and the wheel over one of the outermost sides of the squat crack.

This combination of modelling systems in ANSYS relates to the wheel approaching the crack, passing over it,

and then leaving the crack. Due to the symmetrical nature of the model only one model was needed with the

wheel centred over the side of the crack. The equivalent stress intensity factor was found to peak on the

respective side of the crack in relation to the location of the wheel; which reached up to five times greater in

magnitude. As expected the location of the peak equivalent stress intensity factor around the leading crack

edge is directly related to the positioning of the wheel.

The crack growth angle for the squat crack was then considered for the dynamic analysis of the wheel

traversing over the defect. It was found that in the first model, when the wheel is centred over the squat crack,

there is a desire to change direction and grow downwards at both ends, meanwhile continuing in the direction

of normal growth at other locations. When the wheel is over either side of the crack (the second model) there

is a tendency for the squat crack growth angle to change direction to approximately 60 degrees positive at

close to a distance half way along the leading edge. Considering these two in conjunction depicts the

possibility of the squat crack growing down into the web of the rail to cause fracture. Currently analysing

whether the magnitude of the equivalent stress intensity factors are beyond the threshold considered for crack

growth. Furthermore, a step analysis to impose a residual stress state as the initial state is being considered.

Kuwana, K., Sekimoto, K., Saito, K., Williams, F. A., Hayashi, Y., and Masuda, H. (2007). Can we predict

the occurrence of extreme fire whirls? AIAA JOURNAL, 45(1):16-19

Cost Benefit Analysis of Installing Door Portal at the Domestic Airport

Juliette Lee

The Brisbane airport is the primary airport servicing South-East Queensland for both international and

domestic flights. The domestic terminal uses automatic sliding doors for entry and exit along the east façade.

When the doors activate, cold, inside air spills out to the hot, external air due to the difference in density. As

cold air is lost, the HVAC system must generate more cold air to compensate and therefore, the system

consumes energy. As the domestic terminal has 16,947,053 people passing through each year (BNE 2015), the

energy loses through the entrance has been estimated at 12% of the building’s total energy consumption

(AECOM 2013). Brisbane Airport Corporation has commissioned this study into investigating the energy

saving capabilities of retrofitting the current entrance to a door portal system, without impeding the flow of

foot traffic.

Air exchange and energy consumption have a direct cause and effect relationship which has been extensively

studied. From literature, energy loss via an entrance is a function of pressure, temperature, density, wind,

building dimensions, frequency of door use, door area and door type (Cho et al. 2015). As this research

focuses on retrofitting the current design, many of these variables cannot be altered except the type of door

used. From the three types of doors available, swing, sliding and revolving; the possibilities of a sliding door

was examined further after research concluded the others as impractical.

To decrease air exchange of sliding doors the possibilities of utilising a vestibule was investigated. A vestibule

is a type of door portal, which is a small room with two doors that connects one space to another. By using a

vestibule, direct air exchange of indoor and outdoor air is limited as one door can partially close at any given

time. Vestibules are at their most effective when one of the two doors is completely closed at any instance,

although this can be difficult to achieve. Different vestibule configurations and layout options were developed

from the literature and a variety of retrofitting solutions were brainstormed. Through discussion with the

appropriate stakeholders these initial designs were reduced to three viable options.

These three designs were simulated using computational fluid dynamics to determine their airflow patterns.

By comparing the simulated airflow of the three proposed designs to the current design, conclusions can be

made about the energy saving potential of upgrading the current doors to a door portal system. These potential

savings will be used along with construction quotes to develop a cost benefit analysis of the upgrade. The

results of the analysis will form the basis of the recommendations given to the Brisbane Airport Corporation.

BIBLIOGRAPHY

AECOM, 2013, BAC Domestic Terminal Building: Heat Load Analysis. Brisbane

Mahajan, G., Cho, H., Shanley, K. and Kang, D. 2015, ‘Comprehensive modelling of airflow rate through

automatic doors for low-rise buildings,’ Building and Environment, vol. 87, pp.72-81.

Brisbane Airport Corporation 2015, Brisbane Airport Corporation - Passenger Statistics, viewed 8 Oct 2015,

http://www.bne.com.au/corporate/media-centre/passenger-statistics

B2: Manufacture

SYNOPSES

Springback in Chain-die Forming

Jack J. Brailsford

Roll forming is the process of feeding a metal sheet or strip continuously and progressively through a series of

pairs of forming rolls, in order to create a desired cross-sectional profile (Duggal et al., 1996). As the sheet

passes through each pair of rolls, the sheet undergoes springback and releases the elastic energy stored during

the bending process. Consequently, each roll has to produce significant redundant force prior to plastic

deformation.

More efficient alternatives have been sought out for the production of certain types of metal. With Ultra-High

Strength Steel, the redundant force applied during the formation process is extreme. There is potential for

enormous large roll sizes to resolve this issue. However, roll forming with working radii of up to 50m is

simply unrealistic as well as economically unviable. Chain-die forming consists of die blocks attached to a

chain, running along two (top and bottom) angled chains, simulating extremely large roll forming radii. If

correctly implemented, this new process would effectively replace the current rolling practices resulting in

significantly lower initial capital costs (associated with building one chain die instead of many roll formers)

and ongoing costs (since the redundant force applied in roll forming is observed to be less in the chain-die

forming process).

This thesis investigates the sheet forming of Ultra-High Strength Steel through chain-die forming, utilising

Finite Element Method analysis to simulate the process. For this investigation, the modelling package ANSYS

is primarily used. In particular, it focuses on 2D and 3D modelling of the sheet metal as it undergoes

deformation through the chain die to ultimately determine whether correctional methods are required in order

to minimise the effect of springback within the sheet metal. It will build upon the existing academia

surrounding U-channel chain die casting (the creation of parallel flange channels), which has recently been

designed and manufactured for an industrial prototype (Mysell, 2013). It was proposed that the shape of the

top and bottom die casts requires optimisation to minimise springback forming, while also preventing tearing

of the sheet metal. A concave bend should be implemented along the die base curvature to minimise

springback, while curved corners are designed to prevent tearing.

Using ANSYS, a Finite Element Analysis (FEA) modelling system, two dimensional FEA modelling was

performed, with a simplistic model designed to minimise computation hours. This modelling was then

extrapolated into three dimensions and end states analysed; in order to evaluate how springback has affected

the forming process of a blank, as well as what correctional roll methods may be required. Correct rolls were

modelled using the end result of the blanks from the previous phase as the input geometry for the blanks

BIBLIOGRAPHY

Duggal, N., Ahmetoglu, M. A., Kinzel, G. L., & Altan, T. (1996). Computer aided simulation of cold roll

forming — a computer program for simple section profiles. Journal of Materials Processing Technology,

59(1–2), 41-48. doi: http://dx.doi.org/10.1016/0924-0136(96)02285-6

Mysell, M. (2013). Study of Chain-die Forming through Finite Element Analysis. (Dissertation/Thesis), The

University of Queensland, School of Mechanical and Mining Engineering

Feasibility study for Composite Turbo Compressor Stage

James W. Farrah

One of the greatest challenges facing development and advancement within the field of engineering is the

reduction in weight and improvement of properties for components. One such material which specialises in

these factors is the composite. In general, a composite material is constructed via two or more fundamental

materials which, once combined, results in a material with superior physical and chemical compositions than

the original materials (Barbero 2011). One relatively new application in which composites, specifically fibre-

reinforced polymer composites, has started to arise is in the field line of turbomachinery, and more

specifically in turbochargers. Consisting of a turbine, compressor and housing, a turbocharger’s compressor

offers the greatest potential for possible implementation of composites.

For any material to replace another in a piece of machinery it is important that the new material equals or

exceeds the required properties of the old material. Pertinent to this was an understanding of the mechanical

properties of low alloy steels and aluminium that predominantly make up the impeller market today.

Composite materials consist of a reinforcing fibre and a resin polymer matrix which combine together during

the manufacturing process to give a material its varying improved properties (Campbell 2004). Due to its low

density, high tensile strength and modulus, and other advantageous properties, carbon fibre epoxy was

identified as an ideal material for manufacturing. In the same vein, open moulding, resin transfer moulding,

autoclave / pre-preg along with many other manufacturing methods were considered. Due to the possibility of

high fibre volume fraction composite parts that have low voids and porosity, autoclave / pre-preg has been

identified as a viable manufacturing process (Mallick 2008).

A Garrett turbocharger was disassembled and the compressor impeller obtained to produce an accurate model

of a functioning turbocharger. Using a 3D scanning FaroArm the blade line profiles were incorporated into a

representative Solidworks model for importation into ANSYS for simulation. By first establishing a simple

case validation model, the modal shapes and stresses were determined for the currently used aluminium alloy.

Utilising ANSYS Composite Pre-Post ad-in these results can be compared to those for a carbon-fibre epoxy

material. Whilst simulations show that the composite model can equal and in some cases exceed the properties

of an aluminium counterpart, it appears that the feasibility of a composite impeller lies with its manufacturing

method and cost. Currently an equally spaced six section silicon mould is being produced as the basis for an

initial composite impeller construction.

BIBLIOGRAPHY

Barbero, E. J. (2011). Introduction to Composite Materials Design (2 nd ed.). Florida, US: CRC Press.

Campbell, F. C. (2004). Manufacturing Processes for Advanced Composites. Oxford, UK: Elsevier.

Mallick, P. K. (2008). Fiber-Reinforced Composites: Materials, Manufacturing and Design. Boca Raton:

Taylor &amp; Francis, CRC Press.

Literature Review: Corrosion of Aluminium Alloys for ship building application

Gurpreet Jagpal

Aluminium alloys are a very popular material to use in marine environments due to its low density, high

mechanical properties and high corrosion resistance. Most of these alloys have additions of magnesium and

silicon which enhance these properties. However, it has been found that the hull of ships have been

experiencing high amounts of corrosion despite the aluminium alloy being corrosion resistant. Therefore this

literature review is about investigating what corrosion is occurring and why, as well as finding ways to limit

or prevent the corrosion from occurring.

There has been many findings in where the aluminium alloys have experienced corrosion in marine

environments. However, the type of corrosion has differed, as there is evidence that the aluminium alloys

experience localized corrosion, in particular galvanic, pitting, crevice as well as intergranular corrosion. The

AA6063 alloy has shown signs of erosion-corrosion. From further experiments being carried out,(Pratikno,

2015) found that the way to reduce the rate of corrosion was to apply two aging treatments to the alloy;

artificial aging as well as natural aging, as this gave the best combination and had a much lower corrosion rate

than if the two treatments were applied exclusively. (Pratikno, 2015) In the 5083-H321 alloy, the Mg₂Si have

“anodic behaviour” and corrode through “anodic dissolution”. (Huang et al., 2016) Another reason as to why

the corrosion is occurring is due to the specific environment that the ship is exposed to such as the pressure,

temperature, and water flow and pH level of the seawater. (Bagley et al., 2015) A contributing factor to the

corrosion was that when the ship is moving, the alloy experiences a force from the velocity which makes the

alloy more susceptible to corrosion, but this is an area which requires more research to gain any tangible

conclusions or ways to prevent corrosion from occurring. (Stack et al., 1995) Another avenue to pursue to

ensure that the alloys do not corrode is to apply the same techniques used to protect other metals from

corrosion in marine environments, in particular the use of aluminium composite coatings, where a protective

film ensures that the metal underneath is protected from corrosion. It was found that applying copper based

paint onto ship hulls did not cause corrosion of aluminium alloys, despite, theoretically it would cause it to

become a galvanic cell and the aluminium would sacrificially corrode to protect the copper. However, the

crevice corrosion that occurred was where there were existing crevices present, whereas the rest of the sample

was left unaffected from corrosion. (Bagley et al., 2015)

All these differing environmental factors as well as the specific composition of the aluminium means that it

has been difficult to pin point a specific treatment or processing technique to ensure that the alloys do not

corrode in situ.

BIBLIOGRAPHY

Bagley, F., Atlar, M., Charles, A. & Anderson, C. 2015. The use of copper-based antifoulings on aluminium

ship hulls. Ocean Engineering, 109, 595-602.

Huang, Y., Li, Y., Xiao, Z., Liu, Y., Huang, Y. & Ren, X. 2016. Effect of homogenization on the corrosion

behavior of 5083-H321 aluminum alloy. Journal of Alloys and Compounds, 673, 73-79.

Pratikno, H. 2015. Aging Treatment to Increase the Erosion-Corrosion Resistance of AA6063 Alloys for

Marine Application. Procedia Earth and Planetary Science, 14, 41-46.

Stack, M. M., Chacon-Nava, J. & Stott, F. H. 1995. Relationship between the effects of velocity and alloy

corrosion resistance in erosion-corrosion environments at elevated temperatures. Wear, 180, 91-99.

Development of an Interactive Framework for New Product Development

Kristian Juel

Despite most businesses recognising the importance of continual innovation and improvement, many

businesses do not do well in their New Product Development (NPD) efforts. This thesis aims to produce an

interactive framework for businesses to use to reflect on past NPD successes or failures and plan a process

that suits the particular product in development. To do so requires an understanding of existing approaches in

literature towards planning the NPD process. Secondly, it requires the study of a variety of successful

businesses and their approach to NPD.

The most commonly referenced approaches to NPD include Cooper’s Stage-Gate (2005), which proceeds

linearly from idea conception to launch, or spiral processes that continually cycle from concept planning to

development and testing (Unger and Eppinger 2011). The main shortcoming of existing approaches is that

they are difficult to implement because businesses perceive them as too general and non-adaptable to specific

circumstances. Authors such as Unger and Eppinger (2011) and Meisner and Blessing (2006) propose risk-

based and analytic frameworks for judging the pressures involved with creating a product, while others argue

for an interpretive process (Maffin 1998). However, there is yet to be a convincing framework that

incorporates these two perspectives on adaptive NPD processes into a usable framework for different

products.

Although work is ongoing, this study has established that some businesses leverage their experience to a high

level during NPD and that there is often a high degree of management involvement. None of the businesses

examined so far have actively established a concrete NPD strategy that properly incorporates past experience

and produces a development plan, and there are indications some of the businesses examined would benefit

from such a framework.

Businesses recognise that engaging in an efficient, strategic and planned NPD process is an important

contributor to success. However, businesses currently lack a framework through which to reflect on past

successes and failures, and design a process that suits specific circumstances. While caution and modesty

should be exercised in suggesting a new framework, this remains an exciting topic that deserves more

attention that has been given to it to-date.

BIBLIOGRAPHY

Cooper, RG and Edgett SJ, 2006 Lean, Rapid and Profitable New Product Development, Product

Development Institute, Toronto.

Maffin D, 1998 ‘Engineering Design Models: context, theory and practice’, Journal of Engineering Design,

vol 9, issue 4, pp 315-327.

Meisner, M and Blessing, L, 2006 ‘Defining an adaptive product development methodology’, Proceedings of

the 9th International Design Conference – Design 2006, Dubrovnik, Croatia, pp 69-78.

Unger, D and Eppinger, S, 2011 ‘Improving product development process design: a method for managing

information flows, risks, and iterations’, Journal of Engineering Design, vol. 22, no. 10, pp 689-699.

C2: Thermofluids 2

SYNOPSES

Conjugate Heat Transfer Modelling of Supercritical CO2 in a Parallel Channel

Using Eilmer3

Jack M. Taylor

As a result of the recent push for reduced greenhouse gas emissions, demand for alternative energy generation

methods has increased. One such alternative energy solution is the use of concentrating solar power, which is

popular on both an emissions and efficiency standpoint, especially when paired with carbon dioxide as a

working fluid. As a means of attracting investors to the technology, validation of design specification is

necessary. This is most commonly accomplished through the use of prototypes, which can be very expensive

due to lack of modularity and related manufacturing costs. This is where computational fluid dynamics

models are introduced to ensure design viability and operation before any serious capital outlay.

Conjugate heat transfer (CHT) is the combined effect of convection and conduction across fluid and solid

domains, which is a commonly observed effect in heat exchangers. The work conducted in this thesis aimed to

provide a critical review of literature related to the development of a conjugate heat transfer model for a

simple parallel channel. CHT was addressed depending on the variety of solver/s used; where pre-existing

solutions involving commercial codes such as CFX and FLUENT are explored in literature. The thesis

reviews models and provides recommendations to retrofit solutions to the compressible Navier Stokes flow

solver that is Eilmer.

In analysing existing methods, the main focus was the treatment of the solid-fluid boundaries. The methods

addressed in the thesis were broadly categorised based on the degree of coupling of the solid and fluid regions,

and recommendations were made on the basis of compatibility with Eilmer, computational expense and

accuracy. As it stands the conjugate problem has been addressed by Veeraragavan et al. using a partitioned

approach and finite volume formulations in both the fluid and solid domains. The alternative solutions were

compared to this approach, and validity ranges for various boundary treatments were developed based on

analytical and experimental correlations. In addition to exploring the CHT problem, general model setup was

detailed in regards to: turbulence, meshing, refinement in near wall regions, appropriate solution domains

from experimental work, selection of appropriate heat exchanger and geometry values, exploration of

behaviour through the critical point of carbon dioxide and its impact on model stability, general flow

treatment at boundaries and potential problems/methodologies to address them.

BIBLIOGRAPHY

A. Veeraragavan, J. Beri, R.J. Gollan, Use of the method of manufactured solutions for the verification of

conjugate heat transfer solvers, Journal of Computational Physics, Volume 307, 15 February 2016, Pages 308-

320, ISSN 0021-9991, http://dx.doi.org/10.1016/j.jcp.2015.12.004.

(http://www.sciencedirect.com/science/article/pii/S0021999115008190)

Keywords: Conjugate heat transfer; Method of manufactured solutions; Numerical verification.

Application of Boundary Conditions to Magneto-Hydrodynamic Solver

Lachlan S. Whyborn

Magneto-Hydrodynamics (MHD) is the study of the flow of ionised flows, which occurs in very high energy

fluids such as hypersonic flow and stellar bodies. MHD provides a different challenge to standard

compressible flows, due to the restrictions imposed by the magnetic field. In particular, the no-divergence

constraint on the magnetic field will be violated when using numerical analysis due to the finite nature of the

solvers. A number of methods have been proposed to deal with this no-divergence requirement; the method

chosen by Dr. V Wheatley was the method proposed by Dedner et al. 2002, which is a computationally simple

hyperbolic divergence cleaning method.

This was implemented in the current compressible flow code base used at UQ, Eilmer3, by V. Wheatley and

PhD student D. Bond. The method was shown to be somewhat successful in a case where the boundary

conditions were periodic (i.e. no solid boundaries), but crashed when used in a simulation with solid

boundaries. The desire of the thesis is move the divergence cleaning algorithm to the new code Eilmer4 and

determine a suitable method for dealing with the boundary conditions.

The divergence cleaning algorithm has been implemented into Eilmer4 but is still encountering problems that

were not experienced in Eilmer3. However, recent experiments by Dr. D. Gildfind have produced significant

results using MHD theory, with the shock standoff of hypersonic flow over a blunt nose object being

approximately doubled by the addition of a permanent magnet behind the nose. If the simulations can be

shown to produce similar behaviour, it will be a significant result.

BIBLIOGRAPHY

A Dedner, F. Kemm. D. Kroner, C. D. Munz, T. Schintzer, M. Wesenberg, 2002, Divergence Cleaning for the

MHD Equations, Journal of Computational Physics vol. 175, pg. 645-673

An Unstructured Mesh Generation Code for Eilmer4

Heather A. Muir

The rapid development of computational fluid dynamics (CFD) has enabled major progress in the study of

aeronautics and related sciences in recent times. Over the last 25 years The University of Queensland has

developed its own series of compressible flow simulation codes. Eilmer3 is currently the principle simulation

code for 2D and 3D gas dynamics, and is used for both research and education. Currently the flow solver is

implemented on block-structured grids, which means it is only suitable for the analysis of flows where the

boundary geometry is not overly complex (Jacobs et al. 2014). So what then if it is necessary to model

complex boundary geometry, or fill regions which cannot be easily fit to a four-sided block?

Eilmer4 is currently being developed as a complete rebuild of Eilmer3 (written in C++) in the recently

matured D programming language. The primary motivation behind the rebuild was for ease of maintenance

and student contribution, given the syntactic advantages of D, whilst achieving the equivalent CPU run time

of C. As intended by this reform for student accessibility, this project has seen to the development of an

unstructured mesh generation code to be integrated into the collection of constituent programs of Eilmer4.

The new 2D unstructured mesh generator produces automated, quadrilateral meshes based on the ‘Paving

Algorithm’. By automated it is meant that the mesh self generates over the specified domain from just the

input boundary geometry. An entirely quadrilateral celled mesh has been implemented due to the favourable

properties of quad cells for viscous flow simulations. Of the few existing algorithms built to generate entirely

quad meshes, the Paving Algorithm was chosen based on its wider use in commercial codes. While this

algorithm provides the base concepts for the program, it has been developed from scratch, and so the code

varies in a number of key procedures and incorporates some unique functionality- namely an adjustment to the

smoothing procedure in which a ‘sum of squareness’ evaluation has been paired with the standard Laplacian

vector averaging smoothing, yielding improved results.

The code has been tested on a number of example geometries, and the grid quality has been examined based

on measures of cell aspect ratio, skewness and cell-size uniformity. Whilst these resultant meshes appear

reasonable, it is planned to have the same sample geometries created with the commercial mesh generator

Pointwise®, which also implements a Paving Algorithm, in order to have a direct comparison case. Once

successfully integrated with Eilmer4, simulation results on the unstructured grid can be compared with the

structured grid case, which will also give a measure of the unstructured mesh quality, since it has a direct

impact on the solution accuracy. Having an unstructured grid capability should prove useful for Eilmer4,

provided the generator is robust and able to consistently produce high quality meshes.

BIBLIOGRAPHY

Jacobs, P, Gollan, R & Potter D 2014, The CFCFD Code, School of Mechanical and Mining Engineering, The

University of Queensland, Brisbane, Australia.

School of Mechanical and Mining EngineeringPhone: +61 7 3365 3668

www.mechmining.uq.edu.au