Cumulative Damage Characterization in Glass Fibre Reinforced Plastic by Acoustic Emission under Monotonic and Fatigue Loading

The paper presents a study of changes in mechanical properties of a composite material, glass/epoxy laminate [904, 0]s, and the application of the acoustic emission technique to detect the moment at which cracks start to appear in the material. Monotonic tensile load steps were applied and cracks counted to correlate the number of cracks and the Young’s modulus reduction to the load achieved during each step. Also a fatigue test was performed to check the cumulative damage introduced after different load amplitudes at a frequency if 1 Hz. Results were consistent with those obtained in a previous study by the authors on a similar material. Acoustic emission was used to monitor the formation of cracks in the laminate. The occurrence of cracking seems to wash out low amplitude peaks and, therefore, can be detected using an acoustic emission technique