EFFECT OF GLASS FIBER-MATRIX POLYMER INTERACTION ON FATIGUE CHARACTERISTICS OF SHORT GLASS-FIBER-REINFORCED POLY(BUTYLENE TEREPHTHALATE) BASED ON DYNAMIC VISCOELASTIC MEASUREMENT DURING THE FATIGUE PROCESS

Fatigue behaviors of glass fiber-reinforced poly (butylene terephthala te) (PBT) were studied based on dynamic viscoelastic measurements duri ng the fatigue process. The fatigue strength of glass fiber-reinforced PBT was greatly improved by strengthening the interfacial adhesion be tween glass fiber and matrix PBT. The heat generation rate under cycli c fatigue for PBT reinforced with surface-unmodified short glass fiber was always larger than that reinforced with surface-modified short gl ass fiber because of the large net imposed strain amplitude of PBT mat rix which occurred due to the interfacial debonding under cyclic fatig ue. A fatigue fracture criterion based on the magnitude of hysteresis energy loss being consumed for a structural change was established for the PBT/short glass fiber composites in consideration of glass fiber- matrix polymer interfacial interaction. (C) 1994 John Wiley & Sons Inc .