SEDL / STP / STP1110-EB / STP17738S

Damage-Based Notched Strength Modeling: A Summary

Kortschot, MT
Assistant professor, University of Toronto, Toronto, Ontario

Beaumont, PWR
Lecturer, Cambridge University, Cambridge,

Pages: 21    Published: Jan 1991

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Abstract

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.