Wave propagation analysis of functionally graded bio-composite circular plates using an improved sinusoidal shear deformation theory resting on an advanced viscoelastic foundation

This study investigates the wave propagation characteristics of functionally graded (FG) bio-composite circular plates using an improved sinusoidal shear deformation theory (ISSDT) resting on an advanced viscoelastic substrate. FG bio-composites, composed of natural fibers and biodegradable matrices, offer superior mechanical performance with sustainability benefits, making them ideal for structural applications in aerospace, biomedical, and marine engineering. The ISSDT accounts for transverse shear deformation and thickness stretching effects, enhancing the accuracy of wave dispersion analysis. The governing equations are derived using Hamilton's principle and are solved via the harmonic differential quadrature method (HDQM) along with radial direction, ensuring computational efficiency and precision. The influence of material gradation, boundary conditions, and geometric parameters on phase velocities is examined in detail. The study reveals that increasing the volume fraction of bio-composite constituents significantly alters the wave characteristics, affecting both the fundamental and higher-order wave modes. Additionally, the inclusion of thickness stretching in the ISSDT leads to improved predictions compared to classical and higher-order shear deformation theories. The HDQM proves to be a robust numerical tool, efficiently handling the complex boundary conditions associated with circular FG plates. The findings provide valuable insights into the dynamic behavior of FG bio-composite structures, guiding their optimized design for vibration control and wave manipulation applications. This research contributes to the growing field of sustainable composite materials and advances the understanding of wave mechanics in FG bio-composites.