Air Coupled Ultrasonic ImagingFor Non-Destructive Testing

GTL Ultrasonics

David Lavery

Andrew Ray

Mario Malave

Preliminary Design Review

March 10, 2009

Project Overview Current State of the Project Current Needs Ongoing Development Projected Schedule Market Analysis Future Considerations

Air Coupled Ultrasonics Non-destructive imaging technique

Objectives• Develop a working ACU system using a

novel transducer material• Reduce Cost• Increase Efficiency• Mobile System

A Novel Transducer Material What?

Silver coated polymer-foam High Quasi-Static piezoelectric coefficient

25-700 pC/N Low Acoustic Impedance

0.028 MRayl

A Novel Transducer Material Why?

High frequency transmission to air Increased efficiency Decreased cost

Current State of the Project Working ACU unit which receives both

ultrasonic and electromagnetic signals System reads electromagnetic signals

before ultrasonic

Current Needs Material Characterization Electromagnetic Noise Supporting Circuitry Size Housing Design

Ongoing Development Transducer Optimization

– Extend instability limits– Increase transducer efficiency– Increase piezoelectric coefficient

Size Shape

Ongoing Development• Transducer Optimization

Ongoing Development• Transducer Characterization

– How does the transducer behave in the presence of certain material characteristics

– Based on acoustic pressure across transducer

Ongoing Development• Transducer Characterization

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Ongoing Development Noise Reduction

Antenna Logic circuit Separation of signals

Antenna• Design a copper material which will

border the transducer • Antenna shape will be determined by

the transducer design• Electromagnetic energy (noise) is

received for removal with a differential amplifier circuit

Logic circuit

• Threshold detection – comparator circuit to detect presence of

electromagnetic noise

• Ensure noise has been removed

Separation of signals• Instrumentation amplifier that will remove the

antenna data from the received signal• Bandpass filter the signal to reduce remaining

noise• Amplify the remaining signal for processing

Transducer Signal Processing

Input Signal

Antenna Signal

- AmplifierBandpass

Filter

Image Signal Processing

(Matlab)

Ongoing Development Circuitry

Filter Amplifier Logic Circuit

Circuitry

• Use high GBW op amps• Broken into functional components

Differential Amplifier

• Eliminates background noise• Eliminates electromagnetic noise

Differential Amplifier

Band Pass Filter

• Limits signal to ultrasonic frequencies of interest

• Easily configurable passband

Band Pass Filter

Output Amplifier• Increase gain of final signal• Currently set to 40dB gain

Filter Frequency Response

System Performance

• Most electromagnetic noise suppressed

• Signal amplified 40dB above input signal

Projected Schedule

Task Progress Start End

Circuitry Design In Progress February 25th March 13th

Transducer Characterization In Progress February 23rd March 25th

Circuitry Fabrication Not yet started March 14th March 19th

Transducer Housing Not yet started March 14th March 22nd

Signal Analysis Not yet started March 26th April 10th

Final System Integration Not yet started April 7th April 12th

Market Analysis• Frequently used couplants used for

transmission– Oil, glycerin, and water– Success with air can open a new market of devices

• Possible Device Users– Aviation/Aerospace companies; Boeing, Lockheed

Martin, NASA• NASA Space Shuttle

– Currently uses Laser Dynamic Range Imager (LDRI)

• Only provides superficial data• Air Coupled Ultrasonics (ACU) provides information deeper

than the surface

Updated Parts Cost TablePart Description Quantity Unit Price Price

2'x2' Printed Circuit Board (PCB) 2 $3.45 $6.90

Operational Amplifiers (Op-amp) 10 $1.50 $15.00

Resistor 10 $0.90 $9.00

Capacitor 5 $0.95 $4.75

BNC Connectors 4 $5.00 $20.00

Custom Machined Aluminum 2 $30.00 $60.00

Cellular Polypropylene Foam (1m) 1 $15.00 $15.00

DC Power Supply (400 W) 1 $100.00 $100.00

Cable (10 ft BNC) 1 $20.00 $20.00

Mounting Hardware Kit 1 $20.00 $20.00

Project Total     $270.65

Cost Analysis• 60 Engineering hour for each group member

– $50/hr give a cost of $9000 in labor• 22.8% profit at a sales price of 2,500 ($571 per unit sold)

Future Issues Developing supporting software User interface design