PSI - Issue 17

Elena M. Strungar et al. / Procedia Structural Integrity 17 (2019) 965–970 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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a c Figure 3. Fields of longitudinal deformations with a load of 51 kN, obtained numerically (a) using the method of correlation of digital images (b); photo of the destroyed sample (c) b

5. Conclusion

Using the Vic-3D digital optical system, the deformed state of samples of 3D woven polymeric composite materials based on preforms in the hub area is analyzed. With the help of the video system the evolution of the deformation fields was recorded, the nature of the field heterogeneity was assessed, the mechanical characteristics of the material were determined. The fields obtained showed a non-uniform strain distribution and dependence on the types of reinforcing fibers. In evaluating the mechanical characteristics, materials with the highest elastic properties are noted. In the course of the study, it was found that the crack in the sample extends perpendicular to the axis of the load, which corresponds to the numerical patterns of the strain distribution fields. It was also noted that the strain distribution fields obtained using the digital video system are heterogeneous and asymmetric, which is associated with the heterogeneity of the microstructure of the sample material surface. Large deformations are concentrated in the areas of the recesses, while smaller ones - around the recesses. The morphology of destruction and distribution of deformation fields shows the destruction of composite samples with a hole is associated with the breakage of fiber bundles caused by the technological processing of the material in the immediate vicinity of the hole. The numerical fields of the strain distribution in the region of the stress concentrator qualitatively correspond to the experimental results, and the microstructure of the sample material was not taken into account in the calculation. Thus, the combined use of computational and experimental methods in the design of structural elements complements each of these methods, provides mutual control of experimental and computational data on the stress-strain state of an object and provides a qualitatively new level of design, reliability and performance control of structures.