A Model to Assess Progressive Fatigue Damage in GFRP Composites with layup systems of [0/±45], [90/±45], and [0/±45/0] over Stress Cycles

This study employs an earlier developed stiffness-based model to assess fatigue damage of glass fiber reinforced polymer (GFRP) composites with various layups of [0/±45], [90/±45], and [0/±45/0] under uniaxial stress cycles. The model is constructed based on triphasic damage cracking mechanism in FRP composites and corresponding stiffness reduction of unidirectional plies of 0°, angle-ply laminates of ±45°, and 90° as the number of cycles progresses. The weighting factors η90, η0 and η45 were defined to partition damage of plies in the composite layup systems. Experimental fatigue damage data of [0/±45], [90/±45], and [0/±45/0] composite laminates have fell between the predicted damage curves of 0°, 90° plies and ±45°, 0/±45° laminates over life cycles at various stress levels. Predicted damage results for GFRP laminates showed good agreement with experimental data.