— Quantitative ultrasound (QUS) has shown a great
potential in the assessment of bone characteristics in the recent
research. However, wave propagation in bones is very challenging
due to the nature of multi-layer, anisotropic, and viscoelastic
behaviors. Therefore, our knowledge of wave interaction with bone
structures is far from complete and the resulting wave modes have
not been fully explained. in this study we search to develop a model
for propagation of ultrasonic guided waves in a soft-tissue layer over
a cortical bone layer for inferring estimates of cortical bone properties and New expressions for free guided waves propagating in the
bilayered plate are introduced. .