Intro to PA_short

8/10/2019 Intro to PA_short

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[email protected] www.rd-tech.com

Introduction to Phased Arrays


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What is Phased Array?

Phased-array technology is the ability tomodify electronical ly the acoustic probecharacteristics

Probe modifications are performed byintroducing time shi f tsin the signals sent to(pulse) and received from (echo) individualelementsof an array probe.

Any UT technique for flaw detection andsizing can be applied using phased-arrayprobes.


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Why Phased Array?

High speed electronic scanning without moving parts

Improved inspection capabilities through software

control of beam characteristics

Inspection with multiple angles with single,electronically controlled probe

Many configuration: P/E, T/R, TOFD, Tandem

Greater flexibility for inspection of complex

geometries

Optimized focusing

Optimized beam angle


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What is Phased Array

Array of elements, individually pulsed and time-delayed

Accurate time delays allow constructive and

destructive interference

Arrays permit:

Beam steering

Electronic scanning Lateral scanning

Complex inspections


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a linear array (1D) isbasically a longconventional probe

cut in many smallelements, that can beindividually excited

Design Parameters of Phased-Array Probes


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Phased-Array probes

Wave front

Time

Single Trigger Pulse


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Focalized Beam


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Inclined Beam


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Linear ProbesLinear Scanning


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Linear ProbesAzimuthal Scanning


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Waveforming


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Phased-Array Waveforming

Beam steering using phased-array probe (RECEPTION) : appropriate delays introduced electronically during reception

Only signals satisfying delay law shall be in phase andgenerate significant signal after summation

S


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Focused BeamReceive Side


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Inclinded BeamReceive Side


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Power of the Elements

1 Element

2 Elements

4 Elements

8 Elements


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Beam Focusing


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Beam Focusing

Is the capabil i ty toconverge the acoustic

energyinto a small

focal spotAllows for focusing atseveral depths, using asingle probe

Symmetrical (e.g.parabolic) focal laws(time delay vs.element position)


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Standard phased array focusing

Focus = 30mm Focus = 60mm

30mm

60mm


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Schematic Representation of

Dynamic Depth Focusing

Mechanical Displacement

c = velocity in material

FOCUS DEPTH (PULSER)

DYNAMIC FOCUSING (RECEIVER)

Beamd

isplacement

DDF is an excellent way of inspecting thick components in asingle pulse. The beam is refocused electronically on its return.


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Dynamic Depth Focusing

Standard

phased arrayPhased array with

dynamic depth focusing


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Beam Steering


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Illustration of Sectorial (Azimuthal)

Scanning


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Sectorial Scanning

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N

Sectorial scanning is the ability to scan a complete sectorof volume without any probe movement.

Useful for inspection of complex geometries, or those with

space restrictions

Combines the advantages of a wide beam and/or multiplefocused probes in a single phased array probe


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Electronic (Linear) Scanning


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Electronic (Linear) Scanning

Is the abil i ty to move theacoustic beam along the axisof the array without anymechanical movement.

The beam movement isperformed by timemultiplexing of the activegroup of elements

Scanning extent limited by:

number of elements inarray

number of channels inacquisition system

Active Group


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Combined Beam Processing

Linear combined with steering and focusing


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Weld ScanningConceptual animation showing weld inspection using electronic (linear)

scanning. Emulates typical ASME-type shear wave inspection using linescan (much faster) rather than raster scanning.

Typical weld inspection requires two or more angles with defined raster

size, step size, etc. Need to cover weld, HAZ, any position errors =>

significant amount of scanning


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Phased Array Applications

Large industrial systems installed directly on the mill lineor factory. Typically rack mounted instruments andseparate computer consoles and monitors for operators.

Finished product mill systems for inspection of tubular

products.

Aerospace immersion tank applications.

Automated construction welding

Applications for small portable units such as theOmnsican.


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PV100: TOFD & Pulse Echo For PV Weld

Inspection using MS5800

Technique description

Data Visualization

Results

Advantages


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The Tomoscan system allows forsimultaneous acquisition and

analysis of TOFD and P/E

TOFD

PE 45SW

PE 60SW

Technique Description


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TOFD 60-SW(right)60 SW (left) 45-SW(right)45-SW(left)

Prob

emovement

Data Visualization for TOFD and PE Combined

I ti lt Sh l i


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Inspection results Show examples in

Tomoview

Here TOFD cant find

the indication but PE can do it


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Phased array dove tail blade inspection

Show data in Tomoview


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Omniscan - Small battery operated phased array unit

16 channel pulser, A-scan, B-scan, C-scan, and sector scans.

Programmable for multiple applications.

Omniscan data pictured next four slides.


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Omniscan- inspection of .5 inch plate showing a toe crack


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Omniscan- inspection of .5 inch plate showing a porosity cluster.


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Omniscan- inspection of .5 inch plate showing lack of fusion (LOF).


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Hydrogen induced cracking (HIC)


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Spot inclusions, not interconnected


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Omniscan automated inspection using dual

probe set up with encoded scanner


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Switch monitor to Omniscan-

Show basic features, linear and sectorscans, and automated data

Documents

Intro to PA_short