Ultrasonic phased array imaging of heterogeneous composite structures

Terrien, Nicolas; Centre Technique des Industries Mecaniques Nantes; France

Aschy, A.; CETIM; France
Terrien, N.; CETIM; France
Robert, S.; CEA, LIST; France
Bentahar, M.; LAUM; France

ID: ECNDT-0223-2018
Download: PDF
Session: Composite Material - UT 4
Room: G1
Date: 2018-06-15
Time: 09:20 - 09:40

The aim of this communication is to compare different ultrasonic phased array imaging methods applied on carbon fiber composite structures. First, real time phased array methods as for example focused line scan, single plane wave imaging, dynamic depth focusing… were applied to the inspection of a composite plate and confronted in terms of sensitivity of detection, number of processed signals, acquisition time, total time of inspection and data processing. It was then possible to establish criteria, according to the defect sought and operating conditions, in order to favor the use of a specific imaging method over another by identifying the performances and limitations of each one of them. In case of thicker or more heterogeneous composite plates, it seemed useful to develop an ultrasonic imaging method taking into account the anisotropy and the attenuation of the composite material. Thus the Total Focusing Method and Plane Wave Imaging algorithms were modified by considering the effects of the composite material anisotropy and attenuation on the ultrasonic wave propagation, and thus on the ultrasonic imaging. These modified TFM and PWI algorithms were firstly validated on simulated data and then applied to image a 30-mm-thick carbon fiber composite plate with artificial defects. The performances and the limitations of these modified TFM and PWI algorithms are finally discussed in terms of reliability, resolution, robustness in function of the material properties characterization… and compared to conventional phased array imaging methods (Focused line scan…).