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AIR-COUPLED ULTRASONIC INSPECTION

Water, the most commonly used couplant in ultrasonic testing, is not compatible with certain industrial processes. It may cause permanent damage to many materials, especially to some of the advanced materials used by the aerospace industry. Therefore, QMI developed the unique AIRSCAN?instrumentation and technique, which uses the air of the natural environment as couplant. As such, AIRSCAN is considered a noncontact ultrasonic inspection method. The method also allows to increase the scanning speed without being constrained by any couplant.

SONDA 007 CX

The SONDA 007CX is the multifrequency  AIRSCAN?/sup>  instrument for air-coupled ultrasonic testing. It uses all ceramic transducers for a broad frequency range, from 1 MHz to 50 kHz.  See NEWS.

The SONDA LF 50 is the portable, fully digitized version of air-coupled ultrasonic instruments for low frequency applications.

Inspection of  pultruded and other, highly attenuative materials are successfully tested using the new ceramic transducers at 120 kHz.  Ceramic is  more durable and more robust than any electrostatic transducers. 120 kHz is an optimum combination of good resolution and penetration.  The high frequency of 400 kHz yields the best lateral resolution, while the low frequency of 50 kHz is used for highly attenuative materials.

The following images show C-scans of a paste bonded composite panel with bondline voids.

Att.jpg (5710 bytes) Aa.jpg (15205 bytes)
5 MHz   Water Squirter 400 kHz   Airscan

 

Multifrequency scanning offers an additional tool for defect evalution, as shown in the following C-scans. Note the red color of the defect in the right scan, in contrast to the blue color of the same defect in the left scan. Such frequency dependent transmissions are an indication for increased porosity, as opposed to delaminations.

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400 kHz Airscan 50 kHz Airscan

AIRSCAN?/sup> transducers can be configured to work in through-transmission or pitch-catch mode. This technique is ideally suited for the application of plate waves.

plwtds1.GIF (15709 bytes) plwtds2.GIF (11812 bytes)
Plate Wave Inspection
from one side
Plate Wave Inspection
from opposite sides

 

Typical applications include:

Gr/E Laminates C/C Aircraft Brake Discs Production Feedback Control for Pultrusions
Solar Panels Uncured Prepreg Lay-ups ARALL Panels
Honeycombs Impact Damage Assessment Composite Fan Blades
Perforated Honeycombs Impact Damage Repair Test Aerofoils and Components
Cork Coated Honeycombs Multiple Layer Aluminum Sheet Bonding Composite Aluminum Balsa
Solar Cell Bonding Corrosion Detection (Aged Aircraft) High-Temp Applications
Aircraft Floor Panels Solid Rocket Propellant Fiber Reinforced Pressure Vessels
Foam Sandwich Panels Robotics Sound Sight Recognition (Nuclear) Materials Characterization

 

Air-coupled C-scan

HONEYCOMB SOLAR PANEL

C-scan image with AIRSCAN technique.
Stiffener Insert: 2 in by 2 in.

 

More detailed information about the applications and technique of air-coupled ultrasonic inspection can be found in the following references and links:

You may also contact us directly.

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