Evaluating discrete deformations in masonry using natural feature based DIC

The research presents a methodology for two-dimensional Digital Image Correlation (2D DIC) based on discretely tracking the natural surface features of masonry to characterize its mechanical response. By eliminating any surface treatment, the marker and speckle free DIC provides a non-invasive, realistic and accurate assessment of inherently feature-rich and heterogenous media such as masonry. An experimental campaign was conducted on masonry panels, simulating historical material typologies with stiff blocks and weak mortar joints, subjected to in-plane loading conditions. The ability of the DIC methodology to capture discrete deformations and discontinuities failures, including opening of mortar joints, splitting in brick units and crack propagation, was explored. The emphasis of the research remained on the data processing stage, with elaborate visualization of the deformation patterns, leading to focused analysis and accurate insights on masonry specimen behavior in the case of in-plane loads. Further, while utilizing the natural features, key parameters influencing correlation quality and measurement reliability were identified, establishing guidelines for optimizing data acquisition and processing in heterogeneous materials.