Issue 53

E. M. Strungar et alii, Frattura ed Integrità Strutturale, 53 (2020) 406-416; DOI: 10.3221/IGF-ESIS.53.31 406 Inelastic deformation and destruction of fiber-laminated polymer composites in stress concentration zones Elena M. Strungar, Valery E. Wildemann Perm National Research Polytechnic University, Russia cem.spaskova@mail.ru , http://orcid.org/0000-0002-2246-8638 wildemann@pstu.ru, http: // orcid.org/0000-0002-6240-4022 A BSTRACT . The article is devoted to the experimental study of the laws of inelastic deformation of structural polymer composites in the presence of macroinhomogeneous fields. The work uses a three-dimensional optical system and a method of digital image correlation, thermoscanning equipment. The relationship between the selected parameters of the correlation analysis and the scale level of the deformation processes is shown. Experimental data were obtained confirming the presence of a large-scale effect of strength in a certain range of structural parameter values, data on the features of the deformation of composites with various reinforcement schemes, as well as in the presence of technological defects. Recommendations on the use of a video system for calibration and sensitivity assessment of integrated fiber- optic sensors are presented. K EYWORDS . Experimental mechanics; The method of digital image correlation; Stress concentrator; Fiber-laminated polymer composites; The scale effect of strength Citation: Strungar, E. M., Wildemann, V. E., Inelastic deformation and destruction of fiber-laminated polymer composites in stress concentration zones, Frattura ed Integrità Strutturale, 53 (2020) 406-416. Received: 19.05.2020 Accepted: 24.05.2020 Published: 01.07.2020 Copyright: © 2020 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION ue to their high specific physical and mechanical properties fiber-laminated polymer composite materials are widely used in critical aviation structures. Experimental studies that provide the assessment of evolution of displacement and strain fields in stress concentration zones as well as the specific features of composites behavior in these zones, are necessary for improvement of inelastic behavior models, the development of calculation models and designing the critical structure elements [1-9]. Alongside with various geometry concentrators, in particular, the holes, the structure defects that occur in the process of manufacture or operation may become prospective concentrators [10-14] .  The method of digital image correlation (DIC) is one of promising experimental displacement and strain fields analysis methods. The development of a new method for solution of deformable solid mechanics tasks calls for complex studies of efficacy of the use of experimental mechanics “instrument” with reference to the analysis of mechanical behavior of solids of various geometry and structures during implementation of complex external impact modes [15-21]. This work D