In recent years, photovoltaic (PV) energy has become a cornerstone of sustainable power generation. Nevertheless, ensuring the energy efficiency and long-term reliability of PV panels remains a critical concern, as high operating emperatures, daily heating–cooling cycles, and environmental loads such as wind and snow can induce significant thermo-mechanical stresses on panels and solar cells. To address these challenges, this work developed a two-dimensional finite element method algorithm in Octave to analyze the stress–strain behavior of a PV panel structure under combined mechanical loading and thermal gradient conditions. The simulations, emulating temperature variations between 5:00 and 12:00 hrs with a peak of 50 \(^{\circ }\) C, revealed that steel is the most suitable material, achieving a safety factor of \(15.33,\mu \) compared to aluminum with \(2.59,\mu \) . These findings suggest that steel provides a higher margin of reliability against thermal and mechanical degradation. Safety factors must be interpreted in accordance with structural design standards, which typically recommend values between 1 and 2 for structural applications.