PSI - Issue 37

Francisco Barros et al. / Procedia Structural Integrity 37 (2022) 880–887 Barros et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 7. Absolute displacement field obtained with 3D DIC (subset size: 50 px; step size: 25 px).

Fig. 8. Absolute displacement field and displacement direction obtained with 2D DIC (subset size: 100 px; step size: 50 px).

The mean value over the whole region of interest was of 3.2 mm for the 3D test and 3.1 mm for the 2D test. This means that the obtained results for the 2D and 3D tests were consistent with each other. The order of magnitude and direction of the displacement also match the expected behaviour. There is no visible gradient on the 2D displacement field, which is easily explained by the fact that the field of view only spans a length of the bridge of around 1.4 m. On the 3D test’s displacement field, wh ich covers a larger area with 3.5 m of length, some spatial variation can be seen, although the field is somewhat noisy over the whole region of interest. The image displacements of each subset were, overall, quite small: on the 3D test, the mean image displacement was 1.3 px for the images from Camera A and 2.0 px for the images in Camera B, and on the 2D test, it was 3.1 px.