Evaluation of Porosity in Graphite-Epoxy Composite by Frequency Dependence of Ultrasonic Attenuation

The ultrasonic attenuation of a solid containing a distribution of voids depends on the number of voids per unit volume and the ultrasonic scattering cross-section of the voids. This physical picture has been shown to provide an accurate description of the attenuation behavior of ultrasound in metals containing low level porosity. For example, methods developed from this model for evaluating the average size and the volume fraction of porosity in cast aluminum have yielded good results [1].