4D full-field measurements over the entire loading history: Evaluation of different temporal interpolations

Standard Digital Volume Correlation (DVC) approaches are based on pattern matching between two reconstructed volumes acquired at different stages. Such frameworks are limited by the number of scans (due to acquisition duration), and time-dependent phenomena can generally not be captured. Projection-based Digital Volume Correlation (P-DVC) measures displacement fields from series of 2D radiographs acquired at different angles and loadings, thus resulting in richer temporal sampling (compared to standard DVC). The sought displacement field is decomposed over a basis of separated variables, namely, temporal and spatial modes. This study utilizes an alternative route in which spatial modes are constructed via scan-wise DVC, and thus only the temporal amplitudes are sought via P-DVC. This method is applied to a glass fiber mat reinforced polymer specimen containing a machined notch, subjected to in-situ cyclic tension, and imaged via X-Ray Computed Tomography. Different temporal interpolations were exploited. It is shown that utilizing only one DVC displacement field (as spatial mode) was sufficient to properly capture the complex kinematics up to specimen failure.