Comparison and mechanism analysis of wind-induced vibration responses for flexible photovoltaic structures with different support cable systems based on three-dimensional digital image correlation method

Most existing aeroelastic wind tunnel tests on flexible photovoltaic (PV) support structures focus on single support forms, lacking comparisons of wind-induced vibration responses between different support types and multi-zone/multi-point refined analyses. This study employs a vision-based displacement analyzer and three-dimensional digital image correlation method to obtain high-accuracy flexible PV support structures 3D displacement responses. Investigated structures' wind-induced vibration response evolution laws and mechanisms of single-layer and double-layer cable systems. Results reveal that flexible PV structures exhibit larger displacements and higher-frequency vibrations under 180° wind direction than at 0°. Significant differences exist between the two systems: the single-layer system's response is dominated by vertical displacement across all wind speeds, while the double-layer system transitions from vertical-dominated to coupled vertical-horizontal control at high wind speeds (7.56 m/s). A proposed “axis system transformation for flexural-torsional deformation” mechanism explains this divergence: the single-layer system exhibits “small-lever-arm flexural-torsional” deformation governed by module cables, whereas the double-layer system develops “large-lever-arm flexural-torsional” deformation driven by bearing cables. These findings provide insights for wind-resistant design optimization of flexible PV supports.