Porosity Measurement in Composites Using Ultrasonic Attenuation Methods

The measurement of porosity content in composites has been an area of interest to the NDE community. Theoretical and experimental work have related ultrasonic scattering to the amount of porosity in composites and metals [1]. By monitoring the frequency dependence of the ultrasonic scattering, information concerning the amount of porosity in the material can be determined. The scattering of ultrasonic waves can be measured by monitoring the attenuation of the waves as they travel through a material. To accurately measure the attenuation associated with material properties such as porosity scattering, corrections must be made to the ultrasonic amplitude data. These corrections concern other ultrasonic loss mechanisms that are attributed to the measurement process such as surface or boundary effects and transducer focus effects.