ISO/NP 8203-2

Fibre-reinforced plastics — Non-destructive inspection techniques — Part 2: Ultrasonic — Phased array and air coupled

Scope

This draft operational procedure is intended for mechanized phased array ultrasonic testing techniques (PA-UT) using total focusing method data processing (TFM) and for air-coupled ultrasonic testing technique (AC-UT) applied to non-destructive testing of CFRP and GFRP composite structures.

Advanced mechanized ultrasonic inspection using phased array probes and signal processing or air- coupled probes enables detection, sizing and characterization of a wide range of manufacturing and in-service defects in FRP materials by image evaluation.

By scanning the specimen under test using linear or matrix phased array probes or air-coupled probes, inhomogeneities and discontinuities can be detected and be characterized by the evaluation of C-scan and B-scan images generated by the space-resolved and processed acoustical response from the specimen.

The objectives of testing with phased array probes are:
• Detection of defects, inclusions and inhomogeneities
• Determination of material thicknesses
• Determination of sound velocities
• Determination of lateral defect position and size
• Determination of defect depth (coverage)

The objectives of testing with air-coupled probes are:
• Detection of defects, inclusions and inhomogeneities
• Determination of lateral defect position and size

Usually, phased array measurements are performed from one single side of the specimen. If access to both sides of the structure is possible, additional testing from the opposite side of the test specimen can be performed to increase the inspection outcome.

Inspection with air-coupled probes is usually performed in transmission, meaning that the specimen is placed between the transmitter and receiver.

Phased array inspection can be performed either in contact technique with the use of an adequate couplant or in immersion tank testing using a defined water-path between probe and sample. Air- coupled inspection is performed with the use of air as couplant.
This draft operational procedure consists of a general description, a test instruction and a template for the protocols.