Relationship of damage mechanisms of non-crimp composite with acoustic signal

Abstract

Due to the increase use of laminated composite materials in aircraft structures, and considering that composites have a low damage tolerance, the monitoring of damages in composite structures is necessary. Considering it, this research project proposes to use acoustic signals (collected using the acoustic emission technique), originating from damage mechanisms, to characterize damage in laminated composites during application cyclic loadings and static loadings.The project encompasses composite plates that will be manufactured by RTM (resin transfer molding), and then, this plates will be used for preparing the specimens for fatigue and static tests. For the manufacturing process, it will be employed a monocomponent PRISM" EP2400 epoxy resin system, supplied by CYTEC, and a bidiagonal stitched fabrics (-45º/45º) supplied by SAERTEX, called NCF. The produced fabrics used an intermediated carbon fibers (Hexcel IM7 GP) stitched with PES SC yarns.The fatigue test will be conducted in mode I with a constant loading ratio, and with displacement control. During the loading cycles, a sensor used as an ultrasound receptor will be positioned strategically at the sample in order to monitoring the damage events. After, which the experimental fatigue data and the acoustic emission data will be analyzed and correlated. (AU)