Kenny Van Heuverswijn with ultrasonic phased array technology Inspection time optimization of ...

223 Pages·2008·31.75 MB·English

Inspection time optimization of advanced materials
with ultrasonic phased array technology
Kenny Van Heuverswijn
Promotoren: prof. dr. ir. Joris Degrieck, prof. dr. ir. Wim Van Paepegem
Begeleiders: Geert Luyckx, Ebrahim Lamkanfi
Scriptie ingediend tot het behalen van de academische graad van
Burgerlijk werktuigkundig-elektrotechnisch ingenieur
Vakgroep Mechanische constructie en productie
Voorzitter: prof. dr. ir. Joris Degrieck
Faculteit Ingenieurswetenschappen
Academiejaar 2007-2008

Inspection time optimization of advanced materials
with ultrasonic phased array technology
Kenny Van Heuverswijn
Promotoren: prof. dr. ir. Joris Degrieck, prof. dr. ir. Wim Van Paepegem
Begeleiders: Geert Luyckx, Ebrahim Lamkanfi
Scriptie ingediend tot het behalen van de academische graad van
Burgerlijk werktuigkundig-elektrotechnisch ingenieur
Vakgroep Mechanische constructie en productie
Voorzitter: prof. dr. ir. Joris Degrieck
Faculteit Ingenieurswetenschappen
Academiejaar 2007-2008
Acknowledgements
This master thesis is the final piece of hard work to reach the degree of engineer. It was
a challenging journey through numerous engineering topics including mechanics, electronics,
informatics, physics and automation. I never walked alone and therefore, I wish to acknowledge
the following persons.
First of all, I would like to thank my thesis supervisors Ir. Ebrahim Lamkanfi and Ir. Geert
Luyckx for the countless times we changed ideas, for their assistance on practical matters and
for the time and effort they have put into proofreading my manuscript. Also many thanks to my
promotors prof. dr. Ir. Joris Degrieck and prof. dr. Ir. Wim Van Paepegem for their guidance
and constructive feedback.
Furthermore, I thank technician Luc Vandenbroecke for his helping hand. It was a real pleasure
working with him.
Last but not least, I wish to express my sincere gratitude to my parents for their unconditional
support and for giving me the opportunity to study. Additionally, I would like to send a special
thanks to my girlfriend Jolien who stood by me in good and bad days.
Kenny Van Heuverswijn
Ghent, 10th of June 2008
iv
Inspection time optimization of advanced materials
with ultrasonic phased array technology
KennyVanHeuverswijn
Supervisor(s): prof. dr. Ir. J.Degrieck,prof. dr. Ir. W.VanPaepegem,Ir. E.LamkanfiandIr. G.Luyckx
Abstract—Thisextendedabstractdescribestheimprovementstoanul- achievedontwoways: implementationofnewmotioncontrol-
trasonicscaninspectionfacilityinordertospeeduptesting.Theseinclude linghardware,whichprovidesfasterpositionfeedback,andthe
implementationofnewmotioncontrollinghardwareandtheuseofmulti-
use of multi-element inspection by means of ultrasonic phased
elementscanningwithultrasonicphasedarraytechnology.SeveralC-scans
ofdamagedcompositematerialsmadewiththeimprovedfacilityarepre- arraytechnology.
sented. First,themostimportantimprovementstotheultrasonicscan
Keywords—ultrasonics;ultrasonicphasedarray;nondestructivetesting; inspection facility are discussed. Afterwards follows a closer
LabVIEW;automation
look at the test results obtained with a conventional ultrasonic
apparatus (Krautkramer Branson USIP) and with an ultrasonic
I. INTRODUCTION phasedarrayapparatus(OlympusNDTOmniscanMX).
C
OMPOSITEMATERIALScan be engineered to have a
wide range of flexural, tensile and impact strength prop-
erties. Additionally, theyarecorrosionresistanttomostchem-
icals, donotsufferfromelectrolysisandincorporatelong-term
benefitssuchasweatherabilityandUVstability[1]. Therefore,
theyplayakeyroleinmanystate-of-the-artconstructions,such
asairplanes,windturbinesandsailboats. Inaviationforexam-
ple, the use of composites with high specific strength leads to
significantweightandcostsavings[2].
Despite the enormous amount of advantages, special care
should be taken when using composite materials because they
canbedamagedwithoutanyvisualclue. Forexample,tooldrop
onacompositewingskincaninternallyaffectthemechanicsof
the structure without any visual prove. Secondly, damage can
build-up gradually during use. Finally, discontinuities which
ariseduringproduction,suchasdelaminationsorporosities,can
formathreattothematerialsstrength. Asaconsequence,there
is a need to monitor the internal health of the material during
productionandin-servicetoensuresafety. [3][4]
Ultrasonic nondestructive testing is one of the techniques
usedtosearchforandlocateinternaldefectsordiscontinuities.
Therefore, ultrasound is transmitted into a material and the re-
flectionorthetransmissionisusedtoprovidedetailsonthein-
ternalstateofthematerial.
TheLaboratoryforMechanicalConstructionandProduction
from Ghent University has an ultrasonic scan inspection facil-
Fig.1. Communicationnetworkforultrasonicphasedarrayscanning.
ity with five degrees of freedom which can be used to perform
full automated ultrasonic nondestructive tests. Therefore, the
transducer is continuously moved over the test specimen and II. IMPROVEMENTS
the ultrasonic scan signals are saved together with the position
A. Newmotioncontrollinghardware
into files for further processing. The most important problem
withthisfacilitywastheenormousinspectiontimeduetoslow The existing serial RS-232 connection between the motion
positionfeedbackfromthemotioncontrolhardware,whichcon- controllersandthecomputerhasbeenreplacedbyaCAN1 bus
trolsthemotors, tothecomputer[5][6]. Loweringtheinspec- systemwithahigherdatatransferrate(1MBit/sforCANcom-
tiontimewasthemainobjectiveofthismasterthesiswhichwas paredwith19200kBit/sforRS-232). AlthoughCANcommuni-
cationtakesmorebitstosendacontrolmessage,positionfeed-
K. Van Heuverswijn is a final year mechanical engineering
student at Ghent University (UGent), Gent, Belgium. E-mail: 1CANisshortfor’ControllerAreaNetwork’andisaserialdatacommunica-
[email protected]. tionprotocolwhichwasinternationallystandardized(ISO118981)in1993.
backtakesapproximately17timeslesstimecomparedwithse-
rialRS-232communication(3msforCANcomparedwith50ms
for RS-232). As a consequence, the scanning speeds for per-
formingconventionalscansataresolutionof1mmand0.1mm
arereducedtorespectively42mm/sand6mm/s.
B. Multi-elementscanning
An ultrasonic phased array apparatus (Olympus Omniscan
MX) is integrated into the facility. The transducer connected
to this apparatus has an array of 64 individual piezoelectric el-
ementswhichcanbecontrolledindividually. Themainadvan-
Fig.2. ConventionalultrasonicC-scanofimpactedGFRPplate.Left:reflection
tageisthattheelementsalongthelengthofthetransducercan atcertaindepth.Right:reflectiononglassplateundertheGFRPplate.
be pulsed quickly after each other to collect information over
the complete length of the transducer without movement. Ad-
B. Ultrasonicphasedarrayscans
ditionally, the Omniscan can impose a phase shift between the
pulsationofdifferentelementswhichallowstofocusandsteer ThesameimpactedGFRPplateistestedwiththeOmniscan
theultrasoundbeam. [7] usinga64-elementlinearphasedarraytransducer. Theareaof
The Omniscan needs external encoder feedback to construct 150mmx150mmwasscannedataresolutionof0.1mmwithin
a scanning image and therefore, additional linear magnetic en- twoandahalfminutes. Foraresolutionof1mm,theinspection
coders are installed. They provide a maximum resolution of timeisevenafactor10smaller.
5µm which is even better than the maximum resolution of the
Omniscan (10µm). The scanning image is constructed in the
Omniscan and the computer from the facility is used only for
motioncontrolandpost-processing. Additionally, theinstalled
encoders can also be used to speed up conventional ultrasonic
scans performed with the conventional ultrasonic apparatus.
Thecommunicationnetworkisillustratedinfigure1.
C. Software
New software has been written with LabVIEW to per-
form completely automated conventional C-scans of rectangu-
Fig. 3. C-scan of impacted GFRP plate made with ultrasonic phased array
lar plates with the conventional ultrasonic apparatus as well as technology.Left:unfocusedscan;reflectionatcertaindepth.Right:focused
withtheultrasonicphasedarrayapparatus. Thecommunication scan;reflectionatcertaindepth.
betweenthecomputersoftwareandtheCANbusisdonewitha
USB-to-CANdevicewhichrequiresmorecomplexmotioncon- Theresultofbothanunfocusedandafocusedscan(withfo-
trol software. Extra features are added, such as the possibility cal point in the middle of the plate) is shown on figure 3 (the
toperformadiagonalscantocheckthesetupparameters. Ad- lighter the color, the less energy is reflected to the transducer).
ditionally,thesoftwarecanbeusedtoplotpreviousmadescans, Theimpactdamagecanbeseeninthemiddleofbothimagesas
toshowprevioususedconfigurationparametersandtoplacethe alightercoloredzone. Thefocusedscanseemstoprovidemore
probeperpendicularautomatically. details,howevertheinteractionofthesteeredandfocusedultra-
soundbeamwiththetestspecimenneedsfurtherinvestigation.
III. SCANNINGRESULTS
IV. CONCLUSION
A. Conventionalultrasonicscans
Thismasterthesishaseffectivelyledtoanoptimizationofthe
One of the first experiments was the detection of impact
timeneededtoperformultrasonicscanswiththeultrasonicscan
damage in a glass fiber reinforced plastic (GFRP) plate which
inspectionfacility. Additionally,successfulCscansofdamaged
showednovisualdamageontheimpactedside. Forthisexper-
compositematerialshavebeenmade,bothwithconventionalul-
iment,theUSIPincombinationwithaconventionaltransducer,
trasonic technology and with ultrasonic phased array technol-
which acts both as transmitter and receiver, is used. The new
ogy. The knowledge gained of the Omniscan and the motion
hardwareandsoftwareperformedwellforthisexperiment: the
controlthroughCANcommunicationopensuppossibilitiesfor
damage could be located and the test was performed with an
further use and development of the inspection facility (eg. for
acceptable scanning speed. The area of 150mm x 150mm was
polarscansonwhichtheresearchgroupisworking). Itcanbe
scannedataresolutionof1mmwithin15minutes.
concludedthattheobjectivesofthemasterthesisareachieved.
TheC-scanisillustratedonfigure2(thedarkerthecolor,the
less energy is reflected to the transducer). The impact damage
REFERENCES
canclearlybeseeninthemiddleasablackzonewhichmeans
[1] GeraldMyers,PaulSteinert.TheAdvantageofCompositeMaterialsinthe
less ultrasound is reflected in that zone compared with other,
Design, ConstructionandUseofHard-WallSheltersandContainerSys-
lightercoloredzones. tems,http://www.alkanshelter.com/Advantage.pdf,October2003.
[2] MartineSegers.Glaremaaktvliegtuigengoedkoper,TUDELTA33,2001.
[3] NitinSharma,RolandF.Gibson,EmannuelO.Ayorinde. FatigueofFoam
andHoneycombCoreCompositeSandwichStructures:ATutorial,Journal
ofSandwichStructures8,pp.263-319,July2006.
[4] J.Christophersonetal.AnInvestigationontheEffectofSmallMassImpacts
onSandwichCompositePlates, JournalofCompositeStructures67,pp.
299-306,2005.
[5] D.Vanleene.Optimaliseringengebruikvandeultrasoonopstellingbijhet
onderzoekvanbeschadigdecomposietplaten,UGent,June2006.
[6] G.Luyckx. OntwikkelingvanLabVIEW-programmatuurvoordesturing
vaneenproefstandvoorultrasoononderzoek,UGent,June2003.
[7] M.Moles,C.R.Bird. AdvancesinPhasedArrayUltrasonicTechnology
Applications,R/DTech,Waltham,2004.
Permission to loan
“The author gives the permission to place this master thesis to someone his disposal and copy
parts of this master thesis for personal use.
Anyotherusefallsundercopyrightlaw, speciallywithregardtothelegalcommitmenttoclearly
mention the source when using results from this master thesis.”
The author
Ghent, 10th of June 2008
viii
Inspection time optimization of
advanced materials with ultrasonic
phased array technology
by
Kenny Van Heuverswijn
Thesis submitted to reach the academic degree of
Master of Science in Electromechanical Engineering:
option Mechanical Construction
Academic year 2007–2008
Promotors: prof. dr. Ir. J. Degrieck, prof. dr. Ir. W. Van Paepegem
Supervisors: Ir. E. Lamkanfi, Ir. G. Luyckx
Faculty of Engineering
Ghent University
Laboratory for Mechanical Construction and Production
Chairman: prof. dr. Ir. J. Degrieck
Summary
Ultrasonic nondestructive testing is a method which makes use of ultrasound to search for and
locate defects or discontinuities in a material without damaging it. Ultrasonic sound waves are
transmittedintoamaterialandthereflectedorthetransmittedsoundwavesareusedtoprovide
details on the internal state of the material.
The laboratory for Mechanical Construction and Production has an ultrasonic scan inspection
facilitywith5degreesoffreedomwhichisusedforultrasonicnondestructivetestingofcomposite
materials. The largest problem with this facility was the enormous inspection time due to slow
position feedback. Lowering the inspection time was the main objective of this master thesis,
which was achieved in two ways: the inspection speed was raised with new motion control
hardware and multi-element inspection was implemented by means of ultrasonic phased array
technology.
Thefirstchaptercontainsageneralintroductiontocompositematerialsandtheuseofultrasonic
nondestructive testing for R&D and industry. Additionally, the objective of the master thesis is
discussed. Being able to understand this master thesis into detail, the second chapter contains
a short introduction to conventional ultrasonic testing and ultrasonic phased array technology.
The third chapter contains the history of the ultrasonic scan inspection facility, a description
of its components, the improvements done to the facility and a view on the new LabVIEW
software for performing conventional ultrasonic C-scans on flat plates. The new hardware and
softwarehavebeentestedextensivelyinchapter4, whichalsocontainstheresultofconventional
ultrasonic scans of damaged composite plates.
In chapter 4 and 5, the step to ultrasonic phased array technology is made. Chapter 4 contains
x
first an introduction to the Omniscan MX from Olympus NDT which is an ultrasonic phased
array apparatus the laboratory recently has acquired. The rest of this chapter describes the
integration of the Omniscan MX into the ultrasonic scan inspection, including the software
writtenforperformingC-scansonflatplates. Theresultsofexperimentswiththenewtechnology
are included in chapter 5.
Chapter 6 contains ideas for further use and development of the ultrasonic scan inspection
facility. The conclusions can be found in chapter 7.
Keywords
ultrasonics, ultrasonic phased array, nondestructive testing, LabVIEW, automation