抄録
Failure mechanisms of short glass fiber reinforced poly(ethylene terephthalate) were investigated with particular attention to the effects of fiber volume fraction (Vf＝1 wt.%, 30 wt.% and 60 wt.%). A fracture morphology study was carried out for the surface and for the interior of uniaxial tensile specimens. On the surface, tensile cracks occurring mostly at the fiber ends seemed to be more influential in catastrophic fracture initiation with decreasing Vf. However, the failure mechanisms in the interior were different from those on the surface. For specimens of low Vf (1wt.%), shear bands grew around the fiber ends. A "specific layer" was formed in the matrix along the fiber-matrix interface and shear cracks propagated near the fiber interface in the fiber length direction. The fiber pull-out from the matrix as well as the voiding at the fiber ends, induced by the shear cracks, had strong effect on the fracture initiation. For intermediate and higher Vf (30 wt.% and 60 wt.%), the shear-band induced cracking near the interface caused matrix shear cracking which was the most influential factor in the fracture initiation.
