FEATURE MAPPING FOR ANOMALY IDENTIFICATION IN COMPOSITE MATERIALS AND ADHESIVE BONDS.

Composite materials and adhesively bonded structures often contain anomalies or irregularities that come about either during the fabrication process or develop during the service life of the structure. Some anomalies greatly reduce the strength of the material while others do not impose significant limitations on structural performance. Identification of these anomalies is often possible by employing ultrasonic feature mapping (F-map) techniques. In the F-map process, detection of anomalies is performed by observing either a change in signal amplitude by traditional C-scan analysis, or by noting changes in the feature value in a backwall echo or in a thru transmission signal. Identification is then accomplished by examining features that are developed by using physical models that describe the interaction between anomaly geometry and ultrasonic wave propagation.