|  The
Pocket AU portable scanner system is a computerized PC operated acousto-ultrasonic
(AU) instrument used for the nondestructive inspection of composite materials
and other materials/structures that are difficult to inspect with UT and
other NDT technologies.
The system is based on the acousto-ultrasonic technology that directs
acoustic waveform bursts (a few hundred kHz) into the material being inspected.
An AU receiver recognizes these waveforms and Pocket AU processes the
results and displays them as A-Scan waveforms and C-Scan image maps. The
acoustic signal features include gated Amplitude and Time of Flight, as
well as Energy and other Acoustic Emission parameters, which change when
the acoustic bursts travel through the material and encounter defects
and discontinuities, such as cracks, material property changes, delamination
and debonding. Defects can be easily identified from the C-Scan images.
The Pocket AU system with rolling sensor probe has been successfully
used in the quality inspection of thick composite material and bridge
and concrete structure rehabilitation with fiber-reinforced concrete polymer.
The system also has many distinctive features that make it ideally used
in the field and in applications where other traditional NDT methods are
not practical or successful.
Key Features
- Hand-held portable unit for thick composite material and fiber
reinforced concrete polymer inspection in the field
- PC controlled portable image system for defect inspection
- Integrated battery package lasting up to 4 hours
- Numerical keyboard and LCD screen for showing inspection results
with A-Scan and C-Scan images
- Windows CE software, familiar and easy to operate
- Rolling sensor guided continuous area scan rather than point
reading as with other NDT devices
- C-Scan resolution up to 1/16”
- Scan amplitude and TOF adjustable gate processing
- Permanent digital record of the test results
- Compact Flash card and USB port for data transfer to laptop
or desktop PC
- Capability to detect defects of 6 mm in diameter
|
System Components
The Pocket AU hand-held unit houses a complete Acousto-Ultrasonic subsystem.
It is controlled and operated by a powerful internal computer that uses
Microsoft Windows CE portable operating system. All the advantages of
a Pocket PC computer are available in this hand-held unit, including a
compact Flash card port for securing data files. The system utilizes a
programmable square wave burst generator has the capability to output
single frequency waveform bursts, swept signal (chirp) bursts or complex
frequency varying bursts, while the sensitive AE receiver circuitry processes
the resulting signal through the computer using gated AE feature extraction
and waveform processing techniques. A color LCD screen shows the AU waveforms
or the resultant C-Scan images from the test.
| Results of an FRP-concrete sample inspection using
the Pocket AU System include (a) Good area A-Scan, (b) Debonded Area
A-Scan, (c) C-Scan of the sample showing large and small defects,
(d) Actual FRP concrete sample showing large and small debonds. |
Pocket AU Hand-Held Unit Specification
| • Size: |
9.5" H x 3.5" W x 1.4" D
(241 mm x 89 mm x 36 mm) |
| • Weight (w/ batteries):
|
1.8 lbs. (0.9 kg) |
| • Display: |
3.52” Color LCD, QVGA portrait
mode, 240 pixels wide x 320 high Transflective with LED backlight |
| • Display Touchpad: |
Built-in touchpad on screen for use
with stylus and on-screen processing |
| • Storage Memory: |
128 Mbytes Flash for OS and data
storage |
| • External Interfaces: |
Compact Flash port, USB 2.0 port |
| • Power Consumption: |
Approximately 3 Watts |
| • Power Requirements: |
External DC adapter OR Internal 7.2V
NiMH battery pack, rechargeable
in-situ or optional external charger |
| • Battery Life: |
4 – 6 hours intermittent use |
| • Operating Temperature:
|
32° - 115° F ( 0° - 45° C) |
| • Storage Temperature: |
-4° - 140° F ( -20° - 60° C) |
| • Connectors: |
|  AE
Input:
|
SMB Connector |
| AU
Pulser Output: |
SMB Connector |
| Rolling
Sensor: |
DB-9 connector |
| • Software Selectable Filters |
4th Order Butterworth filters |
| High
Pass Filters: |
20 kHz, 100 kHz |
| Low
Pass Filters: |
200 kHz, 1.0 MHz |
| • AE Channel Description: |
Single channel AE Input using SMB
connector input. Low voltage (5 Volt
Phantom) power is available on the AE
input connector for powering an ex- ternal low voltage preamplifier
or
integral preamplifier sensor* |
| • AE Frequency Response:
|
10.0 kHz to 1.0 MHz |
| • Digitizing: |
16 bit, 5 MSPS ADC |
| • Digital Signal Processing:
|
Performed by dedicated feature
extraction processor |
| • Extracted AU Features:
|
Standard AU features include "gated" Peak
Amplitude and "Time of Flight" measurements, where the user
can
set the gate delay and gate width |
| • Stress Wave Factor: |
Typical AE-AU features (which are also
(AE like features) known in the AU industry as "Stress
Wave Factor" SWF include): Rise Time,
Peak Amplitude, Signal Strength, Dur-
ation, AE Counts, True Energy and RMS |
| • AU Pulser Output: |
Programmable square wave burst out-
put capable of being programmed for
a single frequency output, swept
frequency output or multiple fre-
quency burst output |
| • Min/Max Pulser Freq.: |
50 kHz – 1 MHz |
| • Maximum Duration: |
250 microseconds |
| • Output Voltage: |
20 Volts peak-to-peak |
AU Pulser Output
Programmable square wave burst output capable of being programmed for
a single frequency output, swept frequency output or multiple frequency
burst output.
| • Burst Generator Frequencies: |
50 kHz – 1 MHz |
| • Maximum Duration: |
250 microseconds |
| • Output Voltage: |
20 Volts peak-to-peak |
| The Pocket AU System comes with hand-held, single-channel
AU unit, Rolling Scanner, 2 meter cable and a battery-eliminator DC
power supply (case not shown). |
 AU
Rolling Scanner Unit
The AU Rolling Scanner is designed to operate directly with the Pocket
AU hand-held unit. A spring-loaded, wheeled, rolling Pulser transducer
outputs acoustic bursts into the structure. Meanwhile, a second spring-
loaded, wheeled, rolling Receiver transducer, one inch away, detects and
conditions the structure-modified signals through an on-board AE preamplifier
to the Pocket AU unit. In addition, an encoder, built into the AU Rolling
Scanning unit, measures linear scan motion, while a button built into
the unit provides an index input for developing a C-Scan image map of
the structure.
| • Overall Size: |
5.0” L x 2.9” W x 3.3”
H
(127mm x 74mm x 84mm) |
| • Weight: |
1 lb. (0.45 kg) |
| • Built-in Preamplifier: |
|
| Gain: |
40 dB |
| Bandwidth:
|
10 kHz – 1 MHz |
| • Encoder Resolution: |
0.01" |
Software
Pocket AU comes with a complete working AU software program that uses
A-Scan and C-Scan analysis to perform Acousto-Ultrasonic inspection. The
program is configured just as any other Microsoft Windows program with
a typical menu structure and the familiar menu selections, such as "File,"
"Edit," "Setup," "Run" and "Help."
The "File" menu allows you to Replay, Save, Export or Exit.
The "Edit" menu lets you Cut, Copy and Paste just as in any
other Windows program. The "Setup" menu allows the selection
of the "Pulser" setup menu for setting up the burst generator,
the "A-Scan" mode for setting up the waveform parameters, including
the viewable part of the A-Scan interactively (using waveform start and
length settings), filtering and gate settings for capturing the Peak Amplitude
and Time-of-Flight within the gate. In the "Comments" menu,
a text string relating to the test can be entered. The "Preferences"
menu allows the setting of defaults and control system-wide parameters,
such as selecting the "Directory" for data files, waveform "Capture
Mode," "Units," "File Export Format" and "AutoSave
Settings on Exit." A test is initiated via the "Run" menu.
This test can be a C-Scan test or an A-Scan monitoring of the structure.
The "Help" menu provides information about the Pocket AU system.
|
