Fatigue Behavior of Epoxy and Polyester Resins

Abstract The behavior of an epoxy (Epon 828) and polyester resin (Paraplex P43) have been studied when subjected to cyclic fatigue stresses. A rotating beam fatigue machine was used to apply the stresses which varied from compression to tension (mean stress = 0). The surface temperature of the specimens was recorded by using an infrared temperature detector and the temperature rise was studied as a function of cyclic frequency and stress level. Fatigue life of the materials was studied as a function of cyclic frequency and the influence of moisture on fatigue life was also studied. It has been determined that the temperature rise during fatigue is critical in determining the life of the material. Fractography studies are also discussed and characteristic fracture surface features will be indicated.