Research of the Processes of Eliminating Warpage of Aviation Products Made of Polymer-Composite Materials Obtained by High-Temperature Molding

The article considers issues of identifying the causes and factors that have a significant impact on the occurring and development of the warping process in monolithic products made of polymer — composite materials (PCM) obtained by the method of multidirectional layering of uncured PCM — semi-finished product (prepreg) and subsequent high-temperature molding in an autoclave. Warping is understood as a defect of a PCM product in the form of distortion of its configuration (deformation) under stresses arising during the polymerization of the binder prepreg at a high temperature (1800C) and cooling the product to room temperature. Flat samples made of glass-based prepregs have been researched. The selecting schemes of equilibrium stacking of samples of monolithic panels has been carried out. The influence of the binder content in the prepreg on the deformations in non-equilibrium layouts of the panel samples has been evaluated. It is shown that the most significant factors influencing the occurrence of warpage of monolithic PCM panels are: the weaving pattern of the prepreg reinforcing base, the amount of binder deposited in the prepreg, the direction of stacking monolayers in the panel, the edge effect and the shape of the product surface. It was found that the warpage of the sample occurs along the direction of unbalanced shrinkage of the binder. For balanced stacking, compensation in the direction of binder shrinkage and symmetry with respect to the central layer are necessary; more binder in the prepreg reduces the amount of warpage, but only slightly. The development of constructive and technological recommendations based on the results obtained will lead to a reduction in the terms of development of PCM products.

References

[1] Bondarchuk D.A., Fedulov B.N., Fedorenko A.N., et al. The analysis of residual stresses in layered composites with [0°/90°] layup. Vestnik Permskogo natsional’nogo issledovatel’skogo politekhnicheskogo universiteta. Mekhanik [PNRPU Mechanics Bulletin], 2019, no. 3, pp. 17–26, doi: https://doi.org/10.15593/perm.mech/2019.3.02 (in Russ.).

[2] Molodtsov G.A., Bitkin V.E., Simonov V.F., et al. Formostabil’nye i intellektual’nye konstruktsii iz kompozitsionnykh materialov [Shape-stable and intelligent composite design], Moscow, Mashinostroenie Publ., 2000. 352 p. (In Russ.).

[3] Guseva R.I., Sha Mingun. Producing thin-walled lining plates of carbon fiber in aircraft engineering: a change of process parameters during molding of items made of polymer composite materials. Uchenye zapiski Komsomol’skogo-na-Amure gosudarstvennogo tekhnicheskogo universiteta [Scientific Notes of Komsomolsk-On-Amour State Technical University], 2014, no. 2, pp. 4–12. (In Russ.).

[4] Vasil’yev V.V. Mekhanika konstruktsiy iz kompozitsionnykh materialov [Mechanics of composite constructions]. Moscow, Mashinostroenie Publ., 1988. 268 p. (In Russ.).

[5] Stress and warpage in polymer composite structures reduced. newswise.com: website. URL: https://www.newswise.com/articles/stress-and-warpage-in-polymer-composite-structures-reduced (accessed: 15.04.2021).

[6] Mikhaylin Yu.A. Spetsal’nye polimernye kompozitsionnye materialy [Special polymer composites]. Sankt-Petersburg, NOT Publ., 2009. 658 p. (In Russ.).

[7] Erenkov O.Yu., Koval’chuk S.A. Innovatsionnye tekhnologii polimernykh kompozitsionnykh materialov [Innovative technologies of polymer compotes]. Khabarovsk, Iz-vo TOGU Publ., 2016. 187 p. (In Russ.).

[8] Sonmez F.O., Eyol E. Optimal post-manufacturing cooling paths for thermoplastic composites. Compos. Part A Appl. Sci. Manuf., 2002, vol. 33, no. 3, pp. 301–314, doi: https://doi.org/10.1016/S1359-835X(01)00133-6

[9] Kartashova E.D., Muyzemnek A.Yu. Technological defects of polymeric layered composite materials. Izvestiya vysshikh uchebnykh zavedeniy. Povolzhskiy region. Tekhnicheskie nauki [University Proceedings. Volga Region. Technical Sciences], 2017, no. 2, pp. 79–89, doi: https://doi.org/10.21685/2072-3059-2017-2-7 (in Russ.).

[10] Bitkina O.V. Experimental investigation of the influence of technological factors on the forming of multilayered panels done of composite materials. Vestnik Samarskogo gosudarstvennogo tekhnicheskogo universiteta. Seriya: Tekhnicheskie nauki [Vestnik of Samara State Technical University. Technical Sciences Series], 2013, no. 1, pp. 99–110. (In Russ.).

[11] Burnley L., Correia G. Manipulating fiber orientation for the reduction of warpage in carbon fiber composite sandwich panels. California Polytechnic State University, 2019. 56 p.

[12] Kozlov M.V., Sheshenin S.V., Babkin A.V., et al. Modeling of forming of composites based on thermosetting matrices. Vestnik Voronezhskogo gosudarstvennogo tekhnicheskogo universiteta [Bulletin of Voronezh State Technical University], 2016, vol. 12, no. 6, pp. 11–17. (In Russ.).

[13] Motavkin A.V., Pokrovskiy E.M. Elastic orientational stresses and strains in polymer composites. Vysokomolekulyarnye soedineniya. Seriya A, 2001, vol. 43, no. 12, pp. 2156–2162. (In Russ.). (Eng. version: Polym. Sci. Ser. A., 2001, vol. 43, no. 12, pp. 1280–1285.)

[14] Fedulov B.N., Safonov A.A., Kantor M.M., et al. Modeling of thermoplastic composites solidification and estimation of residual stresses. Kompozity i nanostruktury [Composites and Nanostructures], 2017, vol. 9, no. 2, pp. 102–122. (In Russ.).

[15] Karpov Ya.S., Pavlenko V.N., Stavichenko V.G. Structure and content strength prediction of composite panels with account of temperature impact. Aviatsionno-kosmicheskaya tekhnika i tekhnologiya, 2010, no. 3, pp. 57–64. (In Russ.).