Title :
Quantitative subsurface defect detection in composite materials using a non-contact ultrasonic system
Author :
Cerniglia, Donatella ; Djordjevic, Boro B. ; Nigrelli, Vincenzo
Author_Institution :
Dept. of Mech. & Aeronaut., Palermo Univ., Italy
Abstract :
The results of an experimental study conducted to detect subsurface defects in a thick Gr/PPS composite test sample using a noncontact ultrasonic system are presented. Surface waves are generated by a pulsed laser and detected by an air-coupled capacitance transducer. By controlling the surface wave wavelength through a shadow mask, it is possible to control surface wave penetration depth in the sample. Surface wave peak-to-peak amplitude is related to the near-surface material condition. Results indicate that signal amplitude decreases as the width of the defect increases and an approximately linear relation can be deduced
Keywords :
composite material interfaces; composite materials; surface acoustic waves; ultrasonic materials testing; air-coupled capacitance transducer; approximately linear relation; composite materials; noncontact ultrasonic system; pulsed laser; quantitative subsurface defect detection; shadow mask; signal amplitude; subsurface defects; surface wave peak-to-peak amplitude; surface wave penetration depth; surface wave wavelength; Acoustic transducers; Aerospace materials; Capacitance; Composite materials; Nondestructive testing; Optical pulse generation; Surface acoustic waves; Surface emitting lasers; Surface waves; Ultrasonic transducers;
Conference_Titel :
Ultrasonics Symposium, 2001 IEEE
Conference_Location :
Atlanta, GA
Print_ISBN :
0-7803-7177-1
DOI :
10.1109/ULTSYM.2001.991833
