Ultrasonic Testing in Aviation and Aerospace

Non-Contact Ultrasonic Testing of Fibre Composites

In contrast to conventional ultrasonic testing, no liquid coupling and no direct contact with the test object is required. Air-coupled ultrasonic testing (ACUT) is a well established procedure in the aerospace industry since its first introduction in the 1970s. However, the possibilities of the technology at that time were very limited (defect resolution, sensitivity, software post-processing, modularity, etc.) and were never really further developed.

With the advance of lightweight construction, renewable energies, additive manufacturing, etc., contact-free, air-coupled UT is gaining in importance again. Many components cannot be wetted with liquid coupling due to material or production-dependent properties, such as liquid causing the material to swell, peel, corrode, or otherwise be destroyed. Additionally, air-coupled ultrasound offers the benefit of low, highly penetrating frequency ultrasound combined with the short wavelength in air. This allows the nondestructive inspection of previously untestable composits like thick, multilayer honeycombs, foam cores or green or fiber reinforced ceramics.

Non-Contact Ultrasonic Inspection System SONOAIR

SONOAIR technology enables measurements on the following materials and structures, for example:

• Composites
• Honeycomb structures
• Foams
• Ceramics
• Wood
• Concrete

Phased-Array Ultrasonic Testing with Multi-Element Probes

Phased Array ultrasonic testing (PAUT) requires the use of multi-element probes. By time-delayed excitation of the individual elements the sound field can be shaped and steered. This enables angle sweeps for weld inspection or linear scanning of components to create a volume image of the interior of the part.

Modern TFM technology and powerful 3D software increase the performance of PAUT even further by implementing advanced algorithms to improve the focusing, the image quality and therefore the detectability of the smallest defects, cracks and inclusions. However, these algorithms pose high demands on the quality and performance of the phased array transducers. SONOTEC stands up to that challenge with our customer specific as well as standard phased array transducer lines.