A comparison of stochastic and effective medium approaches to the backscattered signal from a porous layer in a solid matrix
journal contributionposted on 04.12.2012, 11:55 by Valerie PinfieldValerie Pinfield, Richard E. Challis, Robert A. Smith
This paper reports a study of the backscattering behavior of a solid layer containing randomly spaced spherical cavities in the long wavelength limit. The motivation for the work arises from a need to model the responses of porous composite materials in ultrasonic NDE procedures. A comparison is made between models based on a summation over discrete scatterers, which show interesting emergent properties, and an integral formulation based on an ensemble average, and with a simple slab effective medium approximation. The similarities and differences between these three models are demonstrated. A simple quantitative criterion is established which sets the maximum frequency at which ensemble average or equivalent homogeneous medium models can represent echo signal generation in a porous layer for given interpore spacing, or equivalently, given pore size and concentration.
- Aeronautical, Automotive, Chemical and Materials Engineering
- Chemical Engineering