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 terephthalate) (PBT) were studied based on dynamic viscoelastic measurements during the fatigue process. The fatigue strength of glass fiber‐reinforced PBT was greatly improved by strengthening the interfacial adhesion between glass fiber and matrix PBT. The heat generation rate under cyclic fatigue for PBT reinforced with surface‐unmodified short glass fiber was always larger than that reinforced with surface‐modified short glass fiber because of the large net imposed strain amplitude of PBT matrix which occurred due to the interfacial debonding under cyclic fatigue. 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. © 1994 John Wiley & Sons, Inc.