Characterization of Porosity in Thick Composites Using Ultrasonic Wave Velocity Measurements

Abstract

The technique described in the present paper extends the area of application of velocity measurements for characterization of porosity in composite materials. This technique makes it possible to measure the absolute value and dispersion of ultrasonic wave velocity in thick composite laminates independently of the variation of composite thickness using non-contact transducers. The technique was applied to evaluation of porosity in unidirectional 200-ply graphite/ epoxy composite. Experimental results were compared with theoretical calculations and then correlated with void content measurements made by image analysis of photomicrographs of specimen cross-sections. MEASUREMENT