ADVANCES IN COMPOSITE MATERIALS - ECODESIGN AND ANALYSIS

Prediction of mechanical performances of NASC

1.6.1 Prediction of the stress-strain relationship

Since the module of interface is much smaller than that of fibers and the interface thickness is much smaller than the matrix, the load is borne mainly by the fibers and the matrix. When the aspect ratio of the fiber is no larger than a critical value, the stress-strain relationship can be expressed by

Fig. 15. Influence of the fiber volume fraction on the stress distribution

When the aspect ratio of the fibers is larger than the critical value, the relationship between stress and strain can be expressed by

(25)

(26)

£cf = <W і Ef