Issue 46

V. E. Wildemann et alii, Frattura ed Integrità Strutturale, 46 (2018) 295-305; DOI: 10.3221/IGF-ESIS.46.27 304 The evaluation was made regarding the applicability of the method of digital image correlation (DIC) based on the use of the contactless three-dimensional digital optical system Vic-3D to study the mechanisms of the development of internal defects in composites under complex stressed state. Data are obtained on the evolution of the displacement fields and deformation components in the loading process, which characterize the effect of internal defects on the behaviour of layered carbon plastic and deformation mechanisms. The work uses the method of active infrared thermography to identify internal defects in the specimens and determine the actual configuration of delamination. Based on the results of the tests, it was concluded that the use of modern diagnostic tools during studies makes it possible to detect internal defects and analyze the mechanisms of deformation and fracture in specimens of composite materials. It is important to note the prospects of a joint use of optical systems aimed at recording deformation fields and temperatures during the control and diagnostics of seminatural and full-sized elements of composite structures. Based of the obtained experimental data, it can be concluded that for an effective evaluation of a defect development in a composite specimen, it is reasonable to take into account the results not only of tension under static load but also under compression, as well as cyclic effect. A CKNOWLEDGMENTS he study was carried out in Perm National Research Polytechnic University and funded by the Russian Science Foundation according to the research project №15-19-00243. R EFERENCES [1] Senthil, K., Arockiarajan, A., Palaninathan, R., Santhosh, B. and Usha, K.M. (2013). Defects in composite structures: Its effects and prediction methods – A comprehensive review, Composite Structures, 106, pp. 139-149. DOI: 10.1016/j.compstruct.2013.06.008. [2] Lobanov, D.S., Wildemann, V.E., Spaskova, E. M. and Chikhachev, A.I. (2015). Experimental investigation of the defects influence on the composites sandwich panels strength with use digital image correlation and infrared thermography methods. PNRPU Mechanics Bulletin. 4, pp. 159-170. DOI: 10.15593/perm.mech/2015.4.10. [3] Panin, S.V., Burkov, M.V., Byakov, A.V. and Lyubutin, P.S. (2012). A combined method for studying the deformation and fracture of samples from a carbon-carbon composite material from acoustic emission data, the correlation of digital images and tensometry, Siberian Journal of Science, Tomsk Polytechnic University (TPU), 4 (5), pp. 129-138 (in Russian). [4] Panding, W., Hongshuai, L., Xiaolei, Z., Haosen, C., Changxian, W. and Daining, F. (2018). Effect of manufacturing defect on mechanical performance of plain weave carbon/epoxy composite based on 3D geometrical reconstruction, Composite Structures, 199, pp. 38–52. DOI: 10.1016/j.compstruct.2018.05.066. [5] Xie, N., Smith, R. A., Mukhopadhyay, S. and Hallett, S. R. (2018). A numerical study on the influence of composite wrinkle defect geometry on compressive strength, Materials and Design, 140, pp. 7–20. DOI: 10.1016/j.matdes.2017.11.034. [6] Lobanov, D.S., Wildemann, V.E., Spaskova, E. M. and Chikhachev, A.I. (2015). Experimental investigation of the defects influence on the composites sandwich panels strength with use digital image correlation and infrared thermography methods, PNRPU Mechanics Bulletin, 4, pp. 159-170. DOI: 10.15593/perm.mech/2015.4.10. [7] Serovaev, G.S. and Matveenko, V.P. (2016). Numerical study of the response of dynamic parameters to defects in composite structures, Frattura ed Integrità Strutturale, 10(38), pp. 392-398. DOI: 10.3221/IGF-ESIS.38.48. [8] Tashkinov, M.A. (2017). Modelling of fracture processes in laminate composite plates with embedded delamination, Frattura ed Integrità Strutturale, 11 (39), pp. 248-262. DOI: 10.3221/IGF-ESIS.39.23. [9] Tretyakov, M.P., Tretyakova, T.V. and Wildemann, V.E. (2018). Regularities of mechanical behavior of steel 40Cr during the postcritical deformation of specimens in condition of necking effect at tension, Frattura ed Integrita Strutturale, 12(43), pp. 146-154. DOI: 10.3221/IGF-ESIS.43.11. [10] Tretyakova, T.V. and Spaskova, E.M. (2013). Experimental study of limit stress-strain state quasi-brittle material using correlation techniques digital images, PNRPU Mechanics Bulletin, 2, pp. 186-201. T