PSI - Issue 37

O.N. Belova et al. / Procedia Structural Integrity 37 (2022) 888–899 Author name / Structural Integrity Procedia 00 (2021) 000 – 000

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50 mm wide and 5,4mm thick. Material properties of the photoelastic material are Young’s modulus . The geometry of the cracked specimen and schematic representation of the load application are shown in fig. 2. The angle between the crack and the vertical line equals 60 for all specimens. 3 E GPa = , Poisson’s ration 0.3  = and the material fringe constant is found to be 10.41 / f Pa m fringe  =

Fig. 1. Photograph of the experimental apparatus used to visualize and capturing the fringe patterns.

Fig. 2 Test specimen: geometry of the cracked specimen and schematic presentation of the load.

Fig. 3. Digital images obtained from photoelastic measurement experiments: isochromatic images in the plate with two inclined parallel cracks subject to 90 kg, 95 kg and 100 kg. Isochromatic phase maps obtained for the plate with two inclined parallel cracks under different loads are shown in fig. 3. One can see from fig. 3 that it is not possible to provide an accurate description of the stress field in the vicinity of the crack tip considering the one-term asymptotic series expansion only. Fringe tracking and fringe order assignment have become the central topic of current research in digital photoelasticity (Ramesh and Sasikumar (2020)). The skeleton of the fringe is identified first to accurately collect the experimental data from the fringes. The programme is specially developed for the interpretation and processing of experimental data from the photoelasticity measurement experiments. The developed and approved tool allows us to find points that belong to isochromatic