Microstructural characterization in plates using guided wave third harmonic generation

Presently, good understanding of second harmonic generation in a weakly nonlinear plate has been obtained, yet the limited number of primary excitations constrains the use of second harmonics in field measurements. The cumulative characteristics of third harmonic generation in a cubic nonlinear plate has been investigated. The power flux analysis shows that primary wave fields are capable of generating a cumulative third harmonic that is of the same nature. Further synchronism analysis shows that the primary shear-horizontal modes are holo-internal-resonant with third harmonic fields, which will be advantageous in experimental measurements. A nonlinear finite element simulation confirms that the primary SH1 mode generates a cumulative sh3 third harmonic mode.