Bifurcation of static aeroelastic response of thin-walled truncated conical shells

To investigate the aeroelastic instability of thin-shell structures, this article presents a comprehensive wind tunnel experiment focusing on the static aerodynamic response of a thin-walled truncated conical shell structure subjected to low-speed axial airflow. The experiment uncovers significant nonlinear response behavior of the truncated conical shell. As the wind speed increases, the structure initially exhibits a typical small five-petal deformation, followed by an abrupt transition to a large four-petal deformation. To provide a theoretical explanation for the observed bifurcation of this nonlinear response, a simplified calculation model for the steady-state aerodynamic force of the truncated cone shell is proposed. Based on the theory of nonlinear shell deformation, the bifurcation process of the response is calculated and reproduced, accurately capturing the critical wind speed at which the bifurcation occurs. Results indicate that, when considering the geometric nonlinearity of the truncated cone shell structure, the critical speed of system response bifurcation (nonlinear instability speed) is lower than that predicted by a linear system. Furthermore, the system demonstrates different response trajectories during the acceleration and deceleration stages, characterized by complex global bifurcation characteristics. The bifurcation behavior of static aeroelastic response occurring in truncated conical shells can be attributed to the nonlinear buckling problem induced by the "impact" of axial steady-state airflow on the shell.