MEASUREMENT OF THE THERMOMECHANICAL STABILITY OF INTERPHASES BY THE EMBEDDED SINGLE FIBER TEST

In this review of results of the embedded single fiber composite test it is shown that stress transferability in E-glass and carbon fiber reinforced polymer composites can be characterized by a fragment length distribution, and that the mode of failure in most instances can be characterized by a fracture energy criterion. E-glass fiber systems appear to be bounded by fracture energies of the order of 230 J/m2 for well-bonded interfaces to 60 J/m2 for poorly-bonded interfaces, with values being only slightly influenced by temperature. The upper limit of fracture energy in carbon fiber systems may be somewhat lower than in glass fiber systems and the use of higher modulus carbon fiber seems to result in lower fracture energies. Fragment length distributions are sensitive to fiber surface treatment and temperature, and are useful for predicting the strength and stiffness properties of composites.