Mechanical response and silicon cell stress in framed photovoltaic modules under wind loading

Photovoltaic (PV) modules are subjected to environmental loads throughout service, among which wind loading is a critical factor that may induce stress concentration and cracking, thereby degrading the long-term performance of PV systems. In this study, a three-dimensional finite element model of a full-scale PV module was set up to study its mechanical response and silicon cell stress under wind loading. The wind pressure was adopted from published wind tunnel tests of PV module arrays. The static response of prescribed cracks was evaluated using the extended finite element method (XFEM), while the transient stress and displacement responses were evaluated using an implicit dynamic analysis. The numerical results were compared against experimental measurements. Layer stresses and stress concentrations in silicon cells were then evaluated for varying tilt angles, wind incidence directions, and load amplitudes. It is found that the stress level in silicon cells is largely redistributed by the aluminum frame, while the other layers in PV modules are not sensitive to the form of load distribution. Therefore, a uniformly distributed load can be reasonably adopted in future studies on the mechanical response of silicon cells. In addition, transient loading produces amplification of stress and displacement compared with static loading. This study provides an understanding of the mechanical response and stress concentration characteristics of framed PV modules under wind loading and offers theoretical support for the structural design and durability evaluation of PV systems.