Solar Loading Thermography (SLT) has significant advantages in assessing the condition of large structures, particularly for heritage conservation. This technique uses the Solar Loading to detect thermal anomalies on the surface of materials, which may indicate hidden defects or degradation. This study presents a comprehensive methodology for evaluating the structural integrity of wooden columns by integrating infrared non-destructive testing (NDT) under solar loading with digital twin modeling and finite element simulation. The approach utilizes infrared thermography to detect the potential defects, such as soft rot. These anomalies are processed to extract defect contours, which are simplified into geometric shapes to represent the degradation of the material’s elastic modulus. Environmental factors, including wind speed, humidity, and precipitation, are incorporated into the simulation. Wind speed is applied as a loading on the entire ancient wooden structure, with adjustments made based on the column's specific location within the structure, while humidity and precipitation gradients are modeled to simulate their impact on the mechanical properties of the wood. Basic loading parameters, such as bending moments and axial pressure, are manually input into the model, which is then used in the finite element simulation to compute the internal stress distribution within the column. The material properties in the finite element model are dynamically adjusted according to moisture-induced degradation, and the resulting stress distribution is computed in real-time. The 3D stress and deformation distributions are visualized interactively, allowing for detailed inspection of the column’s condition and defect behavior. The system further evaluates the safety of the ancient wooden structure by comparing the computed stress values with established strength theories, providing a safety evaluation indicating whether the defect poses a significant structural risk. This method represents a significant advancement in the preservation and maintenance of heritage wooden structures, as it combines SLT, digital twin modeling, and real-time finite element simulation to enable more accurate and predictive evaluations of ancient wooden structure.

Acknowledgments: This work was supported by the Italian Ministry of University and Research (MUR) (Grant n. PGR02110), and the Ministry of Science and Technology of China (MOST) through the National Key Research and Development Program (2023YFE0197800).