Aeroelastic instability of composite panels in supersonic regime/Instabilità aeroelastica di pannelli compositi in regime supersonico

To study the aeroelastic instability of composite laminated panel under supersonic airflow, in order to analyze it by solving the generalized eigenvalue problem through aeroelastic properties. And generally by calculating the natural frequency of the laminated structure at different incoming flow speeds, the critical instability velocity of the laminated panel under the action of airflow is obtained, because the rigidity of the laminate structure decreases, resulting in structural instability. The structural parameters should be reasonably designed according to the mechanical environment of the composite panels to avoid structural instability problems under the action of airflow. Piston theory was originally developed by Lighthill, on the basis of the extension of Tsien’s hypersonic similitude by Hayes. In the study of panel flutter, many researchers have proposed various aerodynamic computational models in order to better simulate the actual aerodynamic change process, However, the shortcoming of this aerodynamic model lies in the consideration of more complex boundary conditions, so the solution process of the equation is quite complex. In the framework of structural mechanics, two-dimensional models have been used in the derivation of refined aeroelastic models able to predict panel flutter of advanced structure in supersonic range with Piston theory. Piston theory has been used broadly in a number of aerodynamic models, which provides a quasi-steady, point-function relationship between the surface downwash and aerodynamic pressure at a point on a body. This renders piston theory a computationally inexpensive aerodynamic model. In this thesis, The high-efficiency of the CUF tool allows any order model to be derived, Carrera Unified Formulation allows any models to be derived using a compact and unified formulation. A strong form solutions and the finite element approximation of the proposed CUF models. In the paper, the derivation of the characteristic matrices of the FEM for two-dimensional models, the fundamental nuclei allow the matrices to be derived using an automatic procedure. The Finite Element Method (FEM) still deserves important attention due to its versatility and numerical efficiency. The various problems of the mechanics have been addressed, including static, free vibration, and dynamic response problems. in order to analyze it by solving the generalized eigenvalue problem through aeroelastic properties, and many parameters have been considered to investigate their effects on flutter boundaries.