Experimental study of carbon/glass fiber-reinforced hybrid laminate composites with torsional loads by using acoustic emission and Micro-CT

In this work, a torsion experiment was carried out on composite specimens with different off-axis angles to study the damage-evolution behavior of carbon/glass fiber-reinforced hybrid composites. The results show that the off-axis angle can improve the toughness of the specimen during the torsion process and enhance anti-torsion performance in the early stage. After applying Micro-CT and scanning-electron-microscope (SEM) technology, the damage distribution for a composite specimen under torsion was determined. AE technology for monitoring the entire torsion process was also applied, and for damage characterization post-processing based on Fuzzy C-Means (FCM) cluster analysis was performed on collected AE signals. AE signals were clearly divided into three categories that correspond to three damage modes, and frequency characteristics of the AE signal for each damage mode were found. The results can offer guidance for structural health monitoring (SHM) for composites under torsion.