 NDTnetWCNDT '96 - New Delhi Table of Contents |  |
  | Conference Invited Papers |  |
| NDTnet WCNDT '96 - New Delhi Table of Contents | |
| | Conference Invited Papers | |
). Therefore, for an N-layered medium, the most general inverse problem requires the determination of 3N acoustical parameters. For a three-layered medium (N=3) a solution using the through-transmission of a plane longitudinal incident wave in water was presented in [1]. It was shown that theoretically it should be possible to measure six of the nine parameters. However, in practice only four of the six parameters could be measured. In this paper first we will explain why it is not possible to measure the remaining two parameters using that particular technique. We will report a new, supplemental inverse algorithm that has been successfully used to measure the two remaining parameters. Together with the inverse algorithm reported in [1], it is now possible to measure all six parameters simultaneously, i. e., without knowing any of them.
Measurement results for all three thicknesses and all three wavespeeds will be presented for the following specimens:
| | Conference Invited Papers | |