Fatigue life assessment of hybrid bio-composites based on self-heating temperature

An increasing interest to hybrid bio-composites leads to a necessity of their fatigue life assessment, which is a challenging task considering the high influence of selected reinforcing fibres and their composition, as well as anisotropy of natural fibre used more and more often in load-bearing applications. In this study, the influence of hybridization is investigated for flax, glass/flax, Kevlar/flax, and carbon/flax bio-composites in terms of eval-uation of fatigue limit by means of the critical self-heating temperature and acoustic emission approaches as well as microscopic characterization used for justification of the observed phenomena analysing fracture mechanisms. It was shown that the hybridization opens new possibilities of steering fatigue and fracture properties of com-posites. Furthermore, it was confirmed that the critical self-heating temperature determined during fatigue tests can be used as an alternative indicator of the fatigue limit of a composite structure, which was justified by microscopic examination of structures at various levels of fatigue degradation.