We prepare several epoxy-matrix composites using different lengths of 3-m- diameter ZrO2 fibers and find that the

Question:

We prepare several epoxy-matrix composites using different lengths of 3-μm- diameter ZrO2 fibers and find that the strength of the composite increases with increasing fiber length up to 5 mm. For longer fibers, the strength is virtually unchanged. Estimate the strength of the bond between the fibers and the matrix.