Finite element modeling of ultrasonic attenuation and dispersion in graded multilayer polymer composites

Abstract

In this paper, finite element models of ultrasonic wave propagation in Cu–PMMA composites are established. The effects of second-phase particles, ultrasonic properties, and graded interfaces on the ultrasonic propagation behavior are investigated, and the contributions of particle-independent scattering, particle interactions, and matrix viscoelasticity to the ultrasonic attenuation are quantitatively evaluated. The results show that there is no obvious coupling between particle scattering and matrix viscoelasticity in Cu–PMMA composites, and the longitudinal wave speed has little effect with the variation of particle size, ultrasonic frequency, and graded interface, while the variation of the acoustic attenuation coefficient is related to the disorder of ultrasonic energy propagation direction. In the intra-layer uniform model, with the increase in Cu particle size and ultrasonic frequency, the scattering effect of Cu particles on the ultrasonic waves is enhanced, resulting in a significant increase in the acoustic attenuation coefficient. In the inter-layer graded multilayer model, there is a strong reverse energy propagation between the layers, causing the acoustic attenuation coefficient to increase significantly.