Nonlinear flutter analysis of quadrilateral plates consisting of functionally graded carbon nanotubes reinforced composites using Isogeometric Analysis

The current investigation deals with the aeroelastic behavior of quadrilateral plates composed of Functionally Graded Carbon Nanotubes Reinforced Composites (FG-CNTRC) with different distribution models in supersonic airflow using Isogeometric Analysis (IGA). To fulfill this aim, the aeroelastic equations of the mentioned plates are constituted utilizing extended Hamilton's Principle. Hence, First-order Shear Deformation Theory (FSDT) and von Karman's nonlinear strains are exploited to extract structural dynamics equations. The first-order piston theory is utilized to include aerodynamic forces in aeroelastic equations. Carbon nanotube distribution is assumed to be across the thickness either uniformly or non-uniformly and estimated by using the extended rule of mixture. The Isogeometric approach is operated to discretize the obtained relations. The natural frequencies and the flutter boundaries are then attained by applying eigenvalue analysis to the linear aeroelastic model. The flutter behavior of the plates is studied by applying the well-known Newmark method to the mentioned equation. The post-flutter analysis is also conducted by simultaneously applying the Newton-Raphson and Newmark methods to the nonlinear aeroelastic equation. The impacts of nanotube distribution and its volume fraction, flow yaw angle, and geometry on the plates' behavior are investigated. The results are also validated by comparing them with well-known references presented in the literature.