Abstract:
There has been an upsurge in the application of composite materials in the last few decades, due to high demands on their performance in many applications. Most of these applications include the situations where degradation of strength and life by fatigue process is most likely. In this investigation, plane bending fatigue tests have been conducted on glass/ polyester composite laminates with various lamina orientations to investigate fatigue behavior. It has been observed that the probabilistic distribution of fatigue-life of glass-fiber reinforced composites, at a particular stress level, can be modeled by two-parameter Weibull distribution, with high statistical co-relation coefficient. Two methods have been used to obtain the parameters of Weibull distribution. The two-parameter Weibull distribution has also been employed to incorporate failure probability into S–N relationships. For all considered composite laminates, different modes of failure are observed at low and high fatigue stress levels, which establish different damage mechanisms. The results revealed that higher shape parameters are observed at higher stress levels with less scatter in the fatigue-life data indicating a more uniform damage mechanism.