Vibro-acoustic analysis of variable thickness dual-functionally gradient CNT curved plates exposed to thermal environment

Abstract

In recent years, extensive studies on carbon nanotubes-reinforced composites (CNTRC) focus on the uniform-thickness structures and free vibration. However, there is few researches on the vibro-acoustic behaviors of CNTRC structures with variable thickness. Accordingly, this paper constructs a variable thickness double-functionally graded (DFG) sandwich curved plates reinforced by CNTs. The Mori–Tanaka model and mixture rule are used to evaluate the effective elastic modulus of the composite structures. The thermal–mechanical dynamic equation is established using the Hamilton’s principle and solved via Navier’s method combined with the fluid–solid coupling conditions to determine the natural frequency and sound insulation. In calculation, the variable thickness parameters, gradient indices of FG materials, CNT distribution forms, curvature and temperature variations on the vibro-acoustic behaviors are examined. The obtained results show that the curvature of curved plates can significantly increase the vibration frequency and optimize sound insulation characteristics. The coupling effect of material softening and thermal stress under temperature field has a strong suppression effect on vibration frequency, while the nonuniform parameters of variable thickness and the change rate of thickness positively correlate with the vibro-acoustic performances.