Patent ID: 8276431
Filing Date: 2012-10-02
Classification: G01N

Abstract:
1. A method of determining the time for a single transit of an acoustic wave through a test material, comprising: providing a calibration material having known acoustic velocity characteristics, said calibration material having a plurality of sections with each of said sections defining a known thickness; providing an acoustic pitch-catch system that includes a recording structure for recording a received signal as a function of time, said pitch-catch system having a first configuration for the transmission of acoustic shear waves and a second configuration for the transmission of acoustic longitudinal waves; determining a first acoustic zero for said pitch-catch system in said first configuration when said acoustic shear waves are applied at normal incidence by said pitch-catch system to each of said sections of said block; determining a second acoustic zero for said pitch-catch system in said second configuration when said acoustic longitudinal waves are applied at normal incidence by said pitch-catch system to each of said sections of said calibration material; providing a test material of known thickness; coupling said pitch-catch system in said first configuration to the test material such that said acoustic shear waves can be applied at normal incidence to the test material; identifying said first acoustic zero on said recording structure; determining a single transit time for said acoustic shear waves to transit the test material using said pitch-catch system in said first configuration with said first acoustic zero so-identified; coupling said pitch-catch system in said second configuration to the test material such that said acoustic longitudinal waves can be applied at normal incidence to the test material; identifying said second acoustic zero on said recording structure; and determining a single transit time for said acoustic longitudinal waves to transit the test material using said pitch-catch system in said second configuration with said second acoustic zero so-identified.