A non-destructive material characterization framework for retrieving a stiffness matrix using bulk waves

The accuracy of the stiffness matrix used as input in dispersion curve algorithm determine the accuracy of the predicted wave speeds. Common practice is to use standard mechanical testing procedures to determining the E-11, E-22, G(12) and nu(12). The other engineering constants are then based on assumptions such as: E-33 = E-22. The engineering constants are converted to the stiffness matrix and used as input. Due to this approach the dispersion curves can vary significantly from those obtained experimentally. In this research the stiffness matrix components are determined non-destructively using a newly introduced ultrasonic immersion technique, the LAMSS approach. The LAMSS approach utilizes the symmetry planes within an orthotropic transversely isotropic material and the critical angle approach to divide the stiffness matrix retrieval process into several steps to reduce the complexity of the process and increase the accuracy of the solution. As last, the predicted group velocity dispersion curves obtained using a stiffness matrix based on mechanical testing and the ultrasonic immersion technique are compared to experimentally obtained velocities.