Flexural fatigue and failure probability analysis of polypropylene-glass hybrid fibres reinforced epoxy composite laminates

Flexural fatigue tests have been conducted on polypropylene/epoxy composite and its hybrids with glass fibre. Specimens were fabricated in intraply and inter-intraply configurations using the hand lay-up technique. Fatigue tests were performed at a frequency of 25 Hz and zero mean stress. A 20% reduction of the flexural stiffness was taken as a failure criterion. The effects of fibre hybridisation, hybrid configuration and stacking sequence on S-N curves were investigated. The fractured specimens were examined using SEM. Weibull distribution function was used to obtain the failure probabilities and the scatter in the results. Results indicated that hybridising polypropylene fibre with glass improves the flexural fatigue resistance. The fabricated hybrids have economical and specific fatigue strength benefits. The stacking sequence has a great effect on the composite's fatigue resistance. The inter-intraply hybrid laminate with glass fibre layers skin and polypropylene fibre layers core presents the most favourable flexural fatigue behaviour.