NON DESTRUCTIVE EVALUATION OF COMPOSITE MATERIALS USING ULTRASONIC SPECTROSCOPY M. OURAK, B. NONGAILLARD, J. M. ROUVAEN et N. IMOULOUDENEJ. Phys. Colloques, 51 C2 (1990) C2-1261-C2-1264DOI: https://doi.org/10.1051/jphyscol:19902296