Ultrasonic field in layered structure excited by a nanosecond pulsed laser irradiation is numerically simulated by finite element method. Typical calculation is executed for a configuration of a zirconium nitride (ZrN) thin film with different thickness on a steel substrate. The waveforms of surface acoustic wave are presented and the dispersion properties of surface waves in two-layered structure are analyzed by the method of phase spectral analysis, and the results show that the surface wave is anomalous dispersive with the higher frequencies propagating fast than the lower frequencies, and that with the decrease of film thickness, the dispersion of surface wave becomes more serious.
In this paper, the finite element method is used to simulate the laser generated interfacial wave on the transparent solid/solid interface in the thermoelastic region. Typical calculation is performed for the configuration of fused quartz bond to tungsten. Transient waveforms of laser-generated interfacial waves are presented. The results show that with the decrease of film thickness, the amplitude of interfacial waves becomes higher. And the surface waves all have appeared anomalous dispersion with films of different thickness. The simulations can provide theoretical guideline for the understanding of interfacial wave propagation.