PSI - Issue 79

Popa Cosmin Florin et al. / Procedia Structural Integrity 79 (2026) 354–360

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Figure 2 presents the shear specimens in all configurations. On the left a) specimens with couture are depicted and on the right b) specimens without contour.

Fig. 2. Shear Specimens a) with and without contour, b) specimen drawing

The specimens were tested on a Zwick Z005 universal machine (maximum load 5 kN), with the Dantec Q400 DIC system used in each case to measure deformation. The DIC system was beneficial for shear specimens due to the complexity of their geometry and the need to capture strain in the calibration zone. It was also used for tensile specimens, where its measurements were compared with a mechanical extensometer. The tests were carried on at room temperature, and the testing speed was set at 5 mm/min. The specimens prepared for DIC analysis were coated with white paint, followed by the application of a black speckles pattern. This technique allows for non-contact, full-field displacement and strain measurement. The DIC system is equipped with two cameras and a red light to enhance contrast between the white and black speckles. The frame rate during testing was set at 1 Hz, with each camera capturing one image per second, creating an overlapping dataset. The advantage of using the DIC system is that it allows observing of the strain field across the entire specimen surface, rather than being limited to a single area as with a mechanical extensometer. The test setup, with the equipment used, is shown in the image below.

Fig. 3 Setup used for the tests

3. Results and discussion After the measurements were completed, the results were extracted, and the average values for each specimen were plotted for clearer monitoring. The following figures present the Force-Displacement plots for all tensile specimens, both with and without a shell contour. The results show similar trends, with specimens printed at 0 and 90 degrees exhibiting brittle behavior. In contrast, the 45-degree specimens demonstrated a more ductile response, with a smoother and more gradual plastic deformation phase.