Fatigue behavior of high-strength polymers and glass-fiber reinforced polymer composites based on dynamic viscoelastic measurement during the fatigue process

Fatigue behaviors of solid-state extruded high-density polyethylene (HDPE), gel-drawn ultra-high molecular weight polyethylene (UHMWPE), and glass-fiber reinforced poly(butylene terephthalate) (PBT) were studied based on the dynamic viscoelastic measurements during the fatigue process. Fatigue behavior of extruded HDPE showed characteristic fatigue features depending on the type of cyclic straining. It was revealed that fatigue behavior of gel-drawn UHMWPE was sensitive to the crystalline relaxation characteristic. The fatigue performance of glass-fiber reinforced PBT was greatly improved by strengthening the interfacial adhesion between glass fiber and matrix PBT. A fatigue fracture criterion based on the magnitude of hysteresis energy loss consumed for a structural change was established for extruded HDPE and PBT-based composites.