Statistical analysis for fatigue life evaluation of woven E-glass/epoxy composite laminates containing off-centre interacting circular holes

Fatigue behaviour of woven E-glass/epoxy composite laminates containing off-centre interacting circular holes was determined under sinusoidal loading in tension-tension at 0.1 stress ratio. Laminate samples with central hole were also investigated. Tensile and fatigue tests were conducted on specimens in load control mode. For the unnotched, central holed and off-centre interacting holed laminates, fatigue life was evaluated using a two-parameter Weibull distribution function at different probabilities and confidence levels. Results indicated that the number of samples taken at each stress level of fatigue experiments is adequate for the S-N curve generation at 90% confidence level and 90% Weibull probability. From the traditional and mean S-N curves, the effect of scatter on fatigue strengths of the specimens was investigated. Life distribution graphs were constructed to determine the fatigue life at any survival per cent. Damage forms and the associated causes were also explained.

Automated summary

The fatigue behavior of composite laminates under different conditions was studied, fatigue life was determined through testing and statistical methods, and the effect of scatter on fatigue strength as well as the causes of damage were investigated.