Е. М. Strungar, О. А. Staroverov, Е. М. Lynegova

COMPREHENSIVE EVALUATION OF FATIGUE DAMAGE ACCUMULATION AND FAILURE OF SPECIMENS WITH OPERATIONAL STRESS CONCENTRATORS

The paper presents the results of studying the mechanical behavior of laminated carbon-fiber-reinforced plastic under complex low-velocity impact three-point bending followed by cyclic tension. An integrated approach to studying damage accumulation patterns is implemented with the use of state-of-the-art testing and diagnostic equipment. The residual fatigue life of the composite is related to the intensity of preliminary impact bending. The fields of temperature distribution in the active zone of the samples during the tests are shown. Data on damage accumulation obtained by recording acoustic emission signals are presented. Relation of the change in the recorded acoustic response signals to infrared thermal scanning data has been detected, which is supported by the results of an experimental study. The use of additional equipment for infrared thermal scanning and recording of acoustic emission signals gives a complete picture of damage accumulation and failure in composite materials, with a good agreement with experimental data.

Acknowledgments: The experimental study was performed in the Perm National Research Polytechnic University and financially supported by a grant of the President of the Russian Federation for the state support of young Russian scientists (grant No. MK-1545.2022.4). The experimental investigations on estimating fatigue damage accumulation were made under the state assignment from the Ministry of Science and Higher Education of the Russian Federation (No. FSNM-2020-0027).

References:

1. Bogenfeld R., Schmiedel P., Kuruvadi N., Wille T., & Kreikemeier J. An experimental study of the damage growth in composite laminates under tension-fatigue after impact. Composites Science and Technology, 2020, 108082. DOI: 10.1016/j.compscitech.2020.10.
2. Kang K.W., Kim J.K., & Kim H.S. Fatigue Behavior of Impacted Plain-Weave Glass/Epoxy Composites under Tensile Fatigue Loading. Key Engineering Materials, 2005, vols. 297–300, pp. 1291–1296. DOI: 10.4028/www.scientific.net/kem.297-300.1291.
3. Feng Y., He Y., Tan X., An T., & Zheng J. Investigation on impact damage evolution under fatigue load and shear-after-impact-fatigue (SAIF) behaviors of stiffened composite panels. International Journal of Fatigue, 2017, vol. 100 (1), pp. 308–321. DOI: 10.1016/j.ijfatigue.2017.03.046.
4. Cantwell W.J., Morton J. The impact resistance of composite materials – a review. Composites, 1991, vol. 22 (5), pp. 347–362. DOI: 10.1016/0010-4361(91)90549-V.
5. Staroverov O.A., Strungar E.M., Wildemann V.E. Evaluation of the survivability of CFRP honeycomb-cored panels in compression after impact tests. Frattura ed Integrità Strutturale (Fracture and Structural Integrity), 2021, vol. 15 (56), pp. 115. DOI: 10.3221/IGF-ESIS.56.01.
6. Tai N., Yip M., & Lin J. Effects of low-energy impact on the fatigue behavior of carbon/epoxy composites. Composites Science and Technology, 1998, vol. 58 (1), pp. 1–8. DOI: 10.1016/s0266-3538(97)00075-4.
7. Staroverov O.A., Babushkin A.V., Gorbunov S.M. Evaluation of the damage degree to carbon-fiber composite materials under impact. PNRPU Mechanics Bulletin, 2019, No. 1, pp. 161–172. DOI: 10.15593/perm.mech/2019.1.14. (In Russian).
8. Suh S.S., Han N.L., Yang J.M., Hahn H.T. Compression behavior of stitched stiffened panel with a clearly visible stiffener impact damage. Composite Structures, 2003, vol. 62, No. 2, pp. 213–221. DOI: 10.1016/S0263-8223(03)00116-8.
9. Tretyakova T.V., Dushko A.N., Strungar E.M., Zubova E.M., Lobanov D.S. Comprehensive analysis of mechanical behavior and frac- ture processes of specimens of three-dimensional reinforced carbon fiber in tensile tests. PNRPU Mechanics Bulletin, 2019, No. 1, pp. 173–183. DOI: 10.15593/perm.mech/2019.1.15. (In Russian).
10. Tsigkourakos G., Silberschmidt Vadim V., Ashcroft Ian A. Damage analysis of CFRP under impact fatigue. Shock and Vibration, 2012, vol. 19, pp. 573–584. DOI: 10.3233/SAV-2011-0651.
11. Lobanov D.S., Wildemann V.E., Spaskova E.M., Chikhachev A.I. Experimental investigation of the defects influence on the composites sandwich panels strength with use digital image correlation and infrared thermography methods. PNRPU Mechanics Bulletin, 2015, No. 4. pр. 159–170. DOI: 10.15593/perm.mech/2015.4.10. (In Russian).
12. Staroverov O., Tretyakov M., Wildemann V. Tests features of composite materials under complex mechanical loads. IOP Conference. Series: Materials Science and Engineering, 2020, vol. 918. DOI: 10.1088/1757-899X/918/1/012115.

Article reference