Abstract: Through the tensile-fatigue test of glass fiber reinforced vinyl resin matrix composite laminates at different stress levels, the test data are fitted in logarithmic form to obtain the S-N curve. With the decrease of stress amplitude, the number of endurance limit cycles of glass fiber reinforced composites increases significantly, showing a significant increasing trend. At the same time, it is inferred from the curve that when the stress amplitude decreases again, the number of endurance limit cycles will increase more. The failure process is generally degumming at the interface between glass fiber and matrix, glass fiber fracture and matrix crack; stress concentration will occur in this area, and the resin matrix crack continues to expand until the glass fiber is completely separated from the resin matrix, forming layered glass fiber fracture.

Key words: composite, tension tension fatigue, S-N curve, failure analysis