Estudio del comportamiento a fatiga de la delaminación bajo la influencia de un ambiente salino en uniones adhesivas en composites epoxi reforzados con fibra de carbono

Zusammenfassung

This work experimentally analyses the fatigue delamination phenomenon and the fatigue behavior in adhesive joints between two sheets of the same epoxy matrix composite material and carbon fiber reinforcement. The tests were performed using the standardized Double Cantilever Beam (DCB) mode I test. They were carried out in a static and dynamic regime. In a static regime to characterize the critical values of the energy release rate and in a dynamic regime, the fatigue initiation curves G-N and the growth curves G-da/dN were obtained. In addition, the exposure environments (hygrothermal environment and another saline environment) and the exposure periods (without exposure, for one week and twelve weeks) and a relationship of fatigue stress levels of R = 0.1 were determined. For a better interpretation of the experimental results obtained, the experimental data have been treated using a probabilistic model based on a Weibull distribution. The results reveal that in a saline environment the adhesive has a relevant loss of its resistance capacity in its initiation phase, but not in later phases. On the other hand, the crack growth rates of the material subjected to different periods of exposure to said environment are similar and higher than those obtained for the material without exposure.