PSI - Issue 50

S. Lobanov Dmitriy et al. / Procedia Structural Integrity 50 (2023) 163–169 Lobanov Dmitriy S. et al./ Structural Integrity Procedia 00 (2022) 000 – 000

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Fig. 5. Distribution diagram of peak amplitude for fiberglass samples (a), graphs of cumulative energy distribution for fiberglass samples aged in seawater (b).

Graphs of the cumulative energy of AE signals distribution versus loading time are plotted and analyzed for all samples of the structural fiberglass aged in various media. The graphs of the cumulative energy distribution for samples aged at different temperatures and durations in seawater are presented as an example (Fig. 5, b). It is noted that for samples aged in seawater, in process water and in machine oil it is characteristic that the cumulative energy curve for the sample without aging is located above the others. Below this curve are curves for all samples aged at a temperature of 22 ° С with different holding times. The lowest values of cumulative energy are observed for samples aged at a temperature of 60 and 90 ° С with different durations. 4. Conclusions The results of the composites structure degradation are obtained, in particular, the processes of structural components degradation are described, the conditions of exposure (aggressive environment, duration, temperature) are fixed under which surface defects occur in glass and carbon fiber samples in an unloaded state after thermal and moisture aging. Acknowledgements The study was carried out with the financial support of the Russian Foundation for Basic Research within research Project No. 19-41- 590005 r_а. The Experimental studies as part of the description of the mechan ical behavior of structurally inhomogeneous materials were conducted within the State Assignment of the Ministry of Science and Higher Education of the Russian Federation (No. FSNM-2020-0027). References Lobanov D.S., Babushkin A.V., Luzenin A.Yu. 2018. Effect of increased temperatures on the deformation and strength characteristics of a GFRP based on a fabric of volumetric weave. Mechanics of Composite Materials, Vol. 54, No. 5, pp 655-664. Lobanov D. S., Vildeman V. E., Babin A. D., and Grinev M. A. 2015. Experimental research into the effect of external actions and polluting environments on the serviceablity of fiber-reinforced polymer composite materials. Mechanics of Composite Materials, Vol. 51, No. 1, pp. 69-79 Lobanov D. S., Zubova E.M. 2019. Research of temperature aging effects on mechanical behaviour and properties of composite material by tensile tests with used system of registration acoustic emission signal. Procedia Structural Integrity, Vol. 18, pp. 347-352. DOI: https://doi.org/10.1016/j.prostr.2019.08.174 Lobanov D.S. Zubova E.M. 2020. Temperature aging effects on mechanical behavior of structural GFRP on interlaminar shear tests. IOP Conf. Series: Materials Science and Engineering, 747, 012119. doi:10.1088/1757-899X/747/1/012119. Nicholas, J., Mohamed, M., Dhaliwal, G.S., Anandan, S., Chandrashekhara, K. 2016. Effects of accelerated environmental aging on glass fiber reinforced thermoset polyurethane composites. Composites Part B: Engineering, 94, pp. 370-378. Amaro, A. M., Reis, P. N. B., Neto, M. A., & Louro, C. 2014. Effect of different commercial oils on mechanical properties of composite materials. Composite Structures, 118, 1 – 8. DOI:10.1016/j.compstruct.2014.07.017 Lobanov D. S., Strungar E. M., Zubova E. M., Wildemann V. E. 2019. Studying the Development of a Technological Defect in Complex Stressed Construction CFRP Using Digital Image Correlation and Acoustic Emission Methods. Russian Journal of Nondestructive Testing, Vol. 55, No. 9, pp. 631 – 638 Lobanov D.S., Lunegova E.M., Mugatarov A.I. 2021. Influence of preliminary thermal aging on the residual interlayer strength and staging of damage accumulation in structural carbon plastic. PNRPU Mechanics Bulletin, No 1, pp.41-51. DOI: 10.15593/perm.mech/2021.1.05 Harizi, W., Chaki, S., Bourse, G., Ourak M. 2022. Damage mechanisms assessment of Glass Fiber-Reinforced Polymer (GFRP) composites using multivariable analysis methods applied to acoustic emission data. Composite Structures, Vol. 289, 115470. DOI: 10.1016/j.compstruct.2022.115470 Friedrich, L., Colpo, A., Maggi, A., Becker, T., Lacidogna, G., Iturrioz, I. 2021. Damage process in glass fiber reinforced polymer specimens using acoustic emission technique with low frequency acquisition. Composite Structures, Vol. 256, 113105. DOI: 10.1016/j.compstruct.2020.113105 Zhao, W., Pei, N., Xu, Ch. 2022. Experimental study of carbon/glass fiber-reinforced hybrid laminate composites with torsional loads by using acoustic emission and Micro-CT. Composite Structures, Vol. 290, 115541. DOI: 10.1016/j.compstruct.2022.115541