Structural health monitoring of carbon fiber-reinforced laminate composites with torsional loads by using acoustic emission

摘要

To study the damage evolution behavior of composite laminates under torsion process is a challenging task during industry applications. In this work, torsion experiments were carried out on the composite specimens with different off-axis angles to study the damage evolution behavior of carbon fiber-reinforced composites by using acoustic emission, Micro-CT, and the scanning electron microscope (SEM). The collected acoustic signals during torsion were analyzed by fuzzy c-means algorithm, and the results show that the acoustic signals can be divided into three clusters, which correspond to matrix cracking, fiber/matrix debonding, delamination and fiber breakage. These damages were observed and confirmed by applying Micro-CT and SEM. What's more, it is shown that off-axis angle can improve the toughness of the composite specimen during the torsion process. As the off-axis angle increases, the peak frequency of the AE signal for corresponding clusters also increases. Overall, combining AE technique, Micro-CT, and SEM provides guidance for health monitoring of composite structure under torsion with different off-axis angle structures.