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Aircraft damage statistics show that a significant part of the damage is due to the skin fracture - places of rivet joints of sheet duralumin and polymer composite materials. The main factor of their destruction is bearing, which leads to the loss of joint stiffness and the possible sudden failure of the aircraft body. The theoretical calculation of the strength of the rivet joint requires complex mathematical calculations and the development of appropriate numerical methods with further experimental verification of the obtained results. Therefore, it is relevant to develop experimental-calculation methods and technical means for monitoring the condition of multi-row joints of aircraft skin, in particular, to choose a value of reaching the ultimate strength of the joints during bearing. The results of research by the calculation-experimental method of the characteristics of fracture of multi-row rivet connections of sheet materials is proposed. Initially, the bearing stresses with one rivet is studied using prototypes consisting of two duralumin D16-T plates jointed together. The spatial distribution of deformations in the rivet area was evaluated using a portable optical-digital system. Taking into account the spread of experimental data, the value of the maximum load was chosen for the assessment of permissible stresses, under which the deformation of the hole was 2%. According to experimental data, an average diagram of a one rivet joint destruction was established, which was used to determine the stress distribution in the contact elements of a multi-row rivet joint of sheet materials. The proposed experimental-calculation method makes it possible to clarify the deviation of the stress distribution in the contact elements of the multi-row connection from those calculated by standard methods and to discover the most loaded elements in order to optimize the location of the rivets.

1. Pitt, S.; Jones, R. Multiple-site and widespread fatigue damage in aging aircraft. Engineering Failure Analysis. 1997, 4 (4), 237-257. https://doi.org/10.1016/S1350-6307(97)00020-4

2. McEvily, A.J. Metal Failures: Mechanisms, Analysis, Prevention; John Wiley & Sons, 2002. https://doi.org/10.1115/1.1483355

3. Ignatovich, S.R.; Krasnopol'skii, V.S. Probabilistic Distribution of Crack Length in the Case of Multiple Fracture. Strength of Materials. 2017, 49 (6), 760-768. https://doi.org/10.1007/s11223-018-9921-9

4. Donets, O. et al. Structural and technological solutions intended to provide static strength and lifetime of regional passenger aircraft. Open information and computer integrated technologies 2018, 82, 4-26. (In Ukrainian)

5. Huang, W. et al. Fatigue reliability assessment of riveted lap joint of aircraft structures. International Journal of Fatigue. 2012, 43, 54-61. https://doi.org/10.1016/j.ijfatigue.2012.02.005

6. Sakai, T. Bolted Joint Engineering: Fundamentals and Applications; Beuth Verlag GmbH, 2008.

7. Tsai, M.Y.; Morton, J. Stress and Failure Analysis of a Pin-Loaded Composite Plate: An Experimental Study. J. of Comp. Mat. 1990, 24, 1101-1120. https://doi.org/10.1177/002199839002401005

8. Scalea, F.L.; Hong, S.S.; Cloud, G.L. Whole-field Strain Measurement in a Pin-loaded Plate by Electronic Speckle Pattern Interferometry and the Finite Element Method. Experimental Mechanics. 1998, 38 (1), 55-60. https://doi.org/10.1007/BF02321268

9. Maksymenko, O. et al. Digital image correlation technique for thin beam specimen deformation and material moduli of elasticity measurements. Fracture Mechanics of Materials and Structural Integrity, Proceedings of 5th International Conference, Lviv, Ukraine, June 24-27, 2014; Panasyuk, V.V., Ed.; pp 367-372.

10. Ivanyts'kyi, Y.L.; Maksymenko, O.P.; Hvozdyuk, M.M.; Muravskyi, L.I.; Molkov, Yu.V. Method of determining the stiffness of a mechanical connection "composite-metal". UA116508, 2017. (In Ukrainian)

11. Maksymenko, O.P.; Ivanyts'kyi, Y.L.; Hvozdyuk, M.M. Evaluation of the Stiffness of a Composite-Metal Joint by the Method of Digital Image Correlation. Materials Science 2015, 50 (6), 817-823. https://doi.org/10.1007/s11003-015-9788-x

12. Maksymenko, O.P. Fast algorithm of sub-pixel image alignment. Information extraction and processing 2014, 41, 70-76. (In Ukrainian)

13. Maksymenko, O.P.; Sakharuk, O.M. Improving the reliability of 2D DIC by using Fourier-Mellin transform. Digital image correlation advanced methods and applications; Chambers, D., Ed.; Materials Science and Technologies Series; Nova Science Publishers, 2017; pp 1-36.

14. Ivanyts'kyi, Y.L. et al. Evaluation of the Strength of Bolted Joints of Composite Plates. Materials Science. 2019, 55 (2), 265-271. https://doi.org/10.1007/s11003-019-00298-9

15. Maksymenko, O.P. et al. Distribution of Crushing Stresses in Multirow Riveted Joints. Materials Science 2023, 58, 369-376. https://doi.org/10.1007/s11003-023-00673-7

16. Maksymenko, O.P.; Ivanyts'kyi, Y.L.; Hvozdyuk, M.M. Assessment of the strength of mechanical joints of sheet materials by the optical-digital method. Mechanics: modernity and prospects - 2024, Proceedings of the international scientific conference. Lviv, Ukraine, October 7-11, 2024; pp 230-232. (In Ukrainian)

17. Kirkakh, A.B. Problem of the strength of screw connections based on layered composites plastics. Dynamics and strength of machines 2011, 62, 45-54. (In Ukrainian)

18. Dvairin, A.Z. Review and analysis of problem state of experiment-calculated support of design of aircraft units from polymer composites with mechanical junction of parts. Open Information and Computer Integrated Technologies. 2014, 66, 5-19. (In Ukrainian)