Geometrically Nonlinear Vibration of Conical–Cylindrical Assembled Shells Under Thermal–Aerodynamic Loads

Conical–cylindrical assembled shells are typical structural designs of launch vehicles. In addition to thermal stresses from the high-temperature environment, these structures are subjected to external aerodynamic loads during service, leading to a nonlinear stress state in the shells. However, current studies on the vibration behaviors of shells under coupled thermal–aerodynamic loads primarily rely on the linear solution framework, and they are predominantly limited to single-shell structures. To tackle the limitation, a novel theoretical scheme for the vibration of conical–cylindrical assembled shells under thermal–aerodynamic loads, considering geometric nonlinearity, is developed for this study. The original nonlinear governing equation is transformed by applying the perturbation method and the quasi-linearization method, and the obtained nonhomogeneous and homogeneous equations are solved with the precise integration method with and without dimensional expanding, respectively. Additionally, the flutter, thermal buckling, and free vibration analyses are also achieved by adjusting the involved aerodynamic, thermal, and vibration terms in the present scheme. Through extensive solution comparisons across different design parameters involving material properties, geometric parameters, and boundary and loading conditions, the developed scheme demonstrates excellent accuracy. Furthermore, the effects of key parameters on the vibration behaviors are quantitatively investigated. The summarized findings may help facilitate the structural designs of conical–cylindrical assembled shells.