Time-Domain First Born Approximation to Elastodynamic Backscatter from Composite Materials

Abstract

The high specific strengths attainable from composite materials can be negated by pores between the plies in the material. Classical acoustic attenuation measurements can indicate the presence of porosity if all other material properties remain constant. Even though attenuation measurements accurately predict the amount of porosity, its spatial distribution cannot be inferred from these data. To make accurate predictions of structural performance, current micromechanical models of composite materials require accurate estimates of the volume fraction of porosity and its spatial distribution. This work is an attempt to model the acoustic interactions that occur between plane compressional waves and the fiber arrays and pores in order to develop an ultrasonic technique to estimate the spatial distribution and volume fraction of porosity.