Glass Fiber-Reinforced Polyester Composite Fatigue Crack Monitoring

This book presents acoustic emission (AE) technique for detecting onset damage of composite materials damage and validate this technique using actual AE data from fatigue crack growth. Its aims are to improve understanding of the particular characteristics of AE signals; and also to determine the relationship between AE signals and the failure of the material. Time and frequency domain trends were analyzed at five different applied loads (54.2MPa, 60.97MPa, 67.75MPa, 74.52MPa, and 81.30MPa) representing 40% to 60% of the ultimate tensile strength of material. The relevant AE parameters were analyzed both in the early stages of the test and as the material neared the fracture zone. The results showed a high degree of correlation between AE parameters and the number of cycles to failure. This correlation, suggests that AE can be a valuable tool to predict the fatigue life and detect the onset of damage in such composite materials.