Fluid–structure interaction analysis of inflated membrane structures undergoing wind-induced vibration

The aeroelasticity of flexible membrane structures is fundamentally governed by fluid–structure interaction (FSI), yet the coupling between transient vortex dynamics and non-Gaussian structural responses is not fully understood. To resolve this, the aeroelastic behavior of a hexagonal ethylene tetra fluoro ethylene membrane was investigated using concurrent particle image velocimetry laser displacement measurements, and bidirectional FSI simulations. The structure exhibits severe nonlinear amplification: at a normalized wind speed of 1.95, the mean displacement increases by 200% and the root mean square response amplifies by nearly an order of magnitude. The structural curvature drives vibration modal transitions, while leading-edge separation enforces non-Gaussian aerodynamic behavior over 61.5% of the surface, directly influencing fatigue performance. Wind tunnel and numerical data show that the angle of attack dictates vortex shedding patterns; under high angles, the vortex volume increases by 120% with wind speed, shifting the separation zone from the trailing to the leading edge. This mechanism generates a steep spatial gradient in aerodynamic loading, with mean peak suction decreasing from −1.70 at the leading edge to −0.47 downstream. These findings reveal that flexible membrane instability is inherently a fluid-dynamic phenomenon driven by vortex topology evolution and intermittent separation pressures.