Abstract: Since ultrasonic velocities in anisotropic media can change by a factor of 3 or more depending on the direction of propagation, accounting for these changes is extremely important. Also many anisotropic materials are made up of multiple layers of varying orientation, hence the need to account for refraction at ply boundaries. In the present invention, an algorithm is used to calculate these velocities and travel times and properly account for refraction phenomena. Specifically a multilayer SAFT algorithm has been developed that will calculate the time shift, shift and sum A-scan waveforms in layered anisotropic media at any given depth, ply orientation, and number of plies. The algorithm showed an improvement in signal to noise ratio with synthetic data as was expected. This algorithm can be used as a replacement for homogenizing material properties in layered media and will calculate time shifts with increased accuracy since exact material properties are used.

Abstract: Disclosed herein is a method for imaging anisotropic media comprising selecting multiple points within the anisotropic media, which is to be imaged; determining an acoustic path between each selected point in the anisotropic media and a receiver position on the surface of the anisotropic media; calculating an acoustic wave velocity at all necessary points; determining an acoustic path length based on each selected point in the anisotropic media and the receiver position; determining a time delay for each acoustic wave between each image point and the receiver position on the surface of the anisotropic media; calculating a sum for each point selected based on the appropriate acoustic wave velocities and the acoustic path lengths; and generating an image of the anisotropic media using the coherent sums generated for each said image point selected.

Abstract: A method and apparatus are provided for simultaneously measuring the anisotropic orientation and the thickness of an article. The apparatus comprises a transducer assembly which propagates longitudinal and transverse waves through the article and which receives reflections of the waves. A processor is provided to measure respective transit times of the longitudinal and shear waves propagated through the article and to calculate respective predicted transit times of the longitudinal and shear waves based on an estimated thickness, an estimated anisotropic orientation, and an elasticity of the article. The processor adjusts the estimated thickness and the estimated anisotropic orientation to reduce the difference between the measured transit times and the respective predicted transit times of the longitudinal and shear waves.