PSI - Issue 5

Andrzej Katunin et al. / Procedia Structural Integrity 5 (2017) 93–98 Andrzej Katunin et al. / Structural Integrity Procedia 00 (2017) 000 – 000

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4. Conclusions

The performed studies focused on determination of influence of the self-heating effect in the stationary regime on fatigue processes of polymeric composites allows for preliminary evaluation of structural degradation, based on which prediction of residual life of composite structures subjected to such a type of loading is possible. The obtained results show that the degradation initiation in case of stationary self-heating, in contrast to non-stationary self-heating, depends on loading parameters and the self-heating temperature of stabilization significantly influences on a residual life of a composite structure. Moreover, it was observed that the initiation of degradation during stationary self-heating takes place at much lower temperature values than the critical self-heating temperature range determined in the author’s previous studies for non-stationary self-heating. However, formation of a macrocrack in a polymeric matrix occurs after a large number of cycles, which points on domination of mechanical character of degradation. In order to investigate the degradation processes during stationary self-heating a deeper analysis of the collected data including AE and hysteresis evolution in a function of time should be performed. Further studies will be focused on analyzing of the mentioned data for evaluation of the criticality of the self-heating effect in the stationary regime as well as confrontation of the results of the present analysis with results of degradation evaluation during non stationary self-heating using various destructive and non-destructive testing methods. Such an analysis will allow for global evaluation of safe ranges of self-heating temperature in designed and operated polymer-based composite structures and use of the self-heating effect in the determined ranges for non-destructive evaluation of such structures. Ferreira, J.A.M., Costa, J.D.M., Reis, P.N.B., Richardson, O.W., 1999. Analysis of Fatigue and Damage in Glass-Fibre-Reinforced Polypropylene Composite Materials. Composites Science and Technology 59(10), 1461 – 1467. Toubal, L., Karama, M., Lorrain, B., 2006. Damage Evolution and Infrared Thermography in Woven Composite Laminates Under Fatigue Loading. International Journal of Fatigue 28(12), 1867 – 1872. Naderi, M., Khonsari, M.M., 2012. Thermodynamic Analysis of Fatigue Failure in a Composite Laminate. Mechanics of Materials 46, 113 – 122. Liu, Z.Y., Beniwal, S., Jenkins, C.H.M., Winter, R.M., 2004. The Coupled Thermal andMechanical Influence on a Glassy Thermoplastic Polyamide: Nylon 6,6 Under Vibro-Creep. Mechanics of Time-Dependent Materials 8, 235 – 253. Moisa, S., Landsberg, G., Rittel, D., Halary, J.L., 2005. Hysteretic Thermal Behavior of Amorphous Semi-Aromatic Polyamides. Polymer 46(25), 11870 – 11875. Karama, M., 2011. Determination of the Fatigue Limit of Carbon/Epoxy Composite Using Thermographic Analysis. Structural Control and Health Monitoring 18, 781-789. Katunin, A., 2012a. Thermal Fatigue of Polymeric Composites Under Repeated Loading. Journal of Reinforced Plastics and Composites 31(15), 1037 – 1044. Kahirdeh, A., Khonsari, M.M., 2014. Criticality of Degradation in Composite Materials Subjected to Cyclic Loading. Composites: Part B 61, 375 – 382. Naderi, M., Kahirdeh, A., Khonsari, M.M., 2012. Dissipated Thermal Energy and Damage Evolution of Glass/Epoxy Using Infrared Thermography and Acoustic Emission. Composites: Part B 43, 1613 – 1620. Katunin, A. 2012b. Critical Self-Heating Temperature During Fatigue of Polymeric Composites Under Cyclic Loading. Composites Theory and Practice 12(1), 72 – 76. Katunin, A., Krukiewicz, K., Turczyn, R., 2012. Evaluation of Residual Cross-Linking Caused by Self-Heating Effect in Epoxy-Based Fibrous Composites Under Cyclic Loading. Chemik 68(11), 957 – 966. Katunin, A., Wronkowicz, A., Bilewicz, M., Wachla, D., 2017. Criticality of Self-Heating in Degradation Processes of Polymeric Composites Subjected to Cyclic Loading: A Multiphysical Approach. Archives of Civil and Mechanical Engineering, in press, DOI: 10.1016/j.acme.2017.03.003. Katunin, A., Gnatowski, A., 2012. Influence of Heating Rate on Evolution of Dynamic Properties of Polymeric Laminates. Plastics, Rubber and Composites 41(6), 233 – 239. Acknowledgements The results presented in this paper have been obtained within the framework of research grant No. 2015/17/D/ST8/01294 financed by the National Science Centre, Poland. References