Assistant professor, University of Toronto, Toronto, Ontario
Lecturer, Cambridge University, Cambridge,
Pages: 21 Published: Jan 1991
The effect of subcritical damage on the notched strength of cross-ply graphite-epoxy specimens has been studied using 914C/T300 laminates of the family (90j/0j)ns (j = 1,2, n = 1,2,4). Damage was monitored using quasi-real-time radiography and dynamic scanning electron microscopy. In addition, the strain field in the vicinity of the notch tip was mapped using a high-resolution optical technique. A strong relationship between subcritical damage and notched strength is evident in all of the data. A theoretical model that is based on observed damage is briefly summarized. Finite element analysis was used to determine the effect of splitting and delamination on the stress distribution in the 0° ply. All specimens were found to fail when the maximum stress in the 0° ply equaled the strength of this ply. The model predicts the effect of both notch size and layup on strength without the need for empirical parameters.
notched strength, hole size effect, subcritical damage, radiography, scanning electron microscopy, strain measurement, finite element analysis, linear elastic fracture mechanics, splitting, delamination, damage mechanics, composite materials, fracture, fatigue (materials)
Paper ID: STP17738S