PSI - Issue 59

Valerii Kobzar et al. / Procedia Structural Integrity 59 (2024) 344–351 Valerii Kobzar and Oleh Derkach / Structural Integrity Procedia 00 (2023) 000 – 000

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5. Conclusions Experimental techniques for determining damage based on the energy dissipation characteristics of cantilever beams made of woven CFRP involved the use of the AE method to induce local predetermined damage in the specimens were proposed. The experimental research yielded the following conclusions: 1) The experimental studies on quasi-static punching of specimens demonstrated that the approach of recording AE signals exceeding a predetermined threshold enabled a consistent and repeatable attainment of local damage. The repeatability was established based on parameters such as integral AE activity, which represented the total count of pulses. 2) It is shown that changes in the vibration decrement serve as a more sensitive vibrodiagnostic indicator of the presence of local damage in composite beam compared to changes in its natural frequency of vibrations. Thus, it is shown that damping is sensitive to damage located at a third of the cantilever beam length. It is established that for locally damaged beam, the amplitude dependence of the logarithmic decrement exhibited a decreasing character, with a maximum observed at small deformation amplitudes. The proposed experimental techniques hold potential for the development of vibration diagnostic methods. The study contributes to the development of vibration diagnostics methods for composite structures and enhances their functional efficiency and reliability in mechanical engineering applications. References Boginich, O.E., Derkach, O.L., Kobzar, V.L., 2023. Effect of low and elevated temperatures on the dissipative properties of woven carbon fiber plastics. Strength Mater 55, 58 – 68. Cao, M.S., Sha, G.G., Gao, Y.F., Ostachowicz, W., 2017. Structural damage identification using damping: a compendium of uses and features. Smart Mater Struct 26, paper#043001. Derkach, O.L., Zinkovskii, A.P., Onyshchenko, Ye.O., Savchenko, K.V., 2022. Notch-type damage influence on the frequency of the principal mode of the composite cantilever beam flexural vibrations. Procedia Structural Integrity 36, 71 – 78. Grady, J., Meyn, E., 1989. Vibration testing of impact-damaged composite laminates. In: NASA Technical Memorandum 4115. Hammami, M., El Mahi, A., Karra, C., Haddar, M., 2015. Vibration behavior of composite material with two overlapping delaminations. Int. J. of Applied Mechanics 7, paper#1550054. Kabannyk, S., Derkach, O., Savchenko, K., Kruts, V. 2023. An experimental study of notch-type and impact damages influence on nonlinear vibrations of a laminated composite beam. Proceedings of the 29 th International Congress on Sound and Vibration (ICSV29). Kyriazoglou, C., Guild, F.J., 2005. Quantifying the effect of homogeneous and localized damage mechanisms on the damping properties of damaged GFRP and CFRP continuous and woven composite laminates – an FEA approach. Compos Part A 36, 367 – 379. Li, Z., Crocker, M.J., 2006. Effects of thickness and delamination on the damping in honeycomb-foam sandwich beams. Journal of Sound and Vibration 294, 473 – 485. Pérez, M.A. , Gil, L., Oller, S., 2014. Impact damage identification in composite laminates using vibration testing. Composite Structures 108, 267 – 276. Saravanos, D.A., Hopkins, D.A., 1996. Effects of delaminations on the damped dynamic characteristics of composite laminates: analysis and experiments. Journal of Sound and Vibration 192, 977 – 993. Yu, Y.-H., Choi, J.-H., Kweon J.-H., Kim, D.-H., 2006. A study on the failure detection of composite materials using an acoustic emission. Composite Structures 75, 163 – 169.