www.rolls-royce.com NUCLEAR INNOVATION & TECHNOLOGY
CAPABILITY SHEET
COMMISSIONING AND IN-SERVICE SUPPORT
• Extensiveexperienceof use of ultrasound in NDE
• Automatedultrasonictechniques to improve accuracy,speedandreliability
• PhasedArraystoreduce inspection time and cost
• Conformablephasedarraytoinspectcomponents with irregularsurfaces
What is Ultrasonic Inspection?
Ultrasound relates to pressure waves that propagate at frequenciesbeyondtheaudiblerangeofthehumanear.Figure1showsthebasicprincipleofultrasonicinspectionusing a single transducer.
When the ultrasonic wave encounters a defect within thecomponentthewaveisreflectedandscatters,changing the nature of the ultrasonic signal that is obtained by the receiver.
ThesignalrecordedbythereceivingtransducerisknownasanA-Scan,thissignalrepresentstheintensityoftheultrasonicenergythatreachesthereceiverinafixedtimewindow.ExamplesoftheA-Scansobtainedareshown inFigure2.
Rolls-Royce utilises the basic operational principle of ultrasound to inspect a wide range of different components.Anumberofbespoke,automatedscannershave been developed to improve the accuracy, speed and reliabilityoftheinspection.Dataisautomaticallyrecordedandanalysisiscompletedremotelytoreducetheexposureof personnel to ionising radiation.
Ultrasonic InspectionTheuseofultrasoundinNon-DestructiveEvaluation
Figure1.Ultrasonicflawdetectionusingasingletransducer,a)forcomponentswithnodefects,b)foracomponentcontainingadefect
A
B
Figure2.SimulatedA-scans
a)withnodefect b)withadefectpresent
Rolls-Royce Power Engineering plc POBox2000,DerbyDE217BD,England
Tel:+44(0)1332632688 Fax:+44(0)1332622936 Email: [email protected]
www.rolls-royce.com
©2010Rolls-Royceplc
Whilst this information is given in good faith, no warranty or representation is given concerning such information,whichmustnotbetakenasestablishingany contractual or other commitment binding upon Rolls-Royce plc or any of its subsidiary companies.
To maintain inspection performance it is essential to update the phased arraydelaylawsinordertocompensatefortheirregularsurfaceprofileofthe component under test; this effect is shown in Figure 5. This process canbeextremelychallenging;theresearchteamsarecurrentlyworkingtodevelopadvancedalgorithmsformorecomplexgeometriesandinspectiontechniques.
Themembraneprobecanbeusedforbothsurfaceprofilemeasurementand inspection, allowing rapid scanning without the need for multiple angled probes and time consuming mechanical scanning.
NDE–UltrasonicInspection
Metallurgical inspection Capability
Figure4.MembraneProbe
• InnovativeresearchprojectincollaborationwithImperialCollegeLondon
• Membraneprobebenefits:
–Accurate
–Versatile
–Lowcost
–Robust
–RapidScanning
a)forplanesurfacetestpiece
Figure3
Figure5.SectorscanforcompressionalwaveinspectionofsidedrilledholesusingImperial membrane device
b)testpiecewithweldcap when not updating delay laws
c)weldcapwithupdateddelay laws
Ultrasonic Phased Arrays
PhasedArraytransducerstypicallyconsistofalargenumberofidenticalpiezoelectricelements(array)whereeachelementisexcitedataslightlydifferenttime(phased)suchthatitispossibletosteerandfocustheultrasonicbeam;thisisshownschematicallyinFigure3.
Asinglephasedarraytransducercanbeusedtogeneratearangeofdifferent beams; it can therefore be used for multiple inspections.
Phased arrays also allow electronic scanning of a component, which significantlyincreasesinspectionspeedandhencereducescost.
Conformable Ultrasonic Phased Arrays
In contact ultrasonic inspection it is essential to maintain coupling between the transducer and the component under test.
Whenusingconventionalultrasonictechniquesitisnotalwayspossibletomaintaincontactandachieve100%testcoverageofcomponentswithirregular surfaces.
Rolls-RoyceisworkingwithImperialCollegeLondontoresearchanddevelop a new conformable phased array device that allows reliable ultrasonicinspectionofcomponentswithcomplexgeometries.
This low-cost membrane device, that uses a standard phased array, couplestothecomponentsurfaceviaafluidstandoffencapsulatedbyalow-loss membrane and is shown in Figure 4.
• Improvedaccuracy
• Fasterscanning
• Reducedinspectiontimeandhencecost
7166/CS.04/Aug10
Recommended
