Stress concentration effect on the fatigue properties of carbon nanotube/epoxy composites

This study experimentally investigates the stress concentration effect on the fatigue properties of multi-walled nanotube (MWCNT)/epoxy nanocomposites by employing the dumbbell type specimens with central through-hole notches. Both the hole sizes and the CNT contents are considered as the experimental variables. The experimental results show that the fatigue strengths of the notched nanocomposites decrease with an increase in hole sizes. The notch sensitivity factors increase with the notch root radii and the ultimate strengths of the nanocomposite specimens. This study employed a mathematical model to relate the notch sensitivity with the hole size and a material constant, and this employed material constant was found to depend on the ultimate strength rather than the CNT contents of the nanocomposites.