Effect of residual stress on the matrix fatigue cracking of rapidly cured epoxy/anhydride composites

There is an increasing demand for rapid cure resin systems for high-volume production of composite structures, especially for the automotive sector. While shortening production time, rapid cure cycles often lead to high residual thermal stresses in the structure. This study investigates the impact of residual stress on the onset of fatigue induced matrix micro-cracking in carbon-epoxy composites made of rapid curing resin. The effect of residual stress on the onset of fatigue induced matrix cracking was predicted using a simplified analytical model with the assumption of plane stress. A good agreement is observed between the analytical prediction and experimental results, however, further validation is required to assess the model's potential in accelerating the design and certification of composite structures to meet fatigue endurance requirements.