Registration of acoustic emission in composite material by fiber-optic sensors based on adaptive interferometer

Paper presents the results of studying the features of recording acoustic emission waves recorded by fiber-optic sensors. Fiber-optic sensors are used as an elastic medium that receives acoustic emission waves. For this purpose, the optical fibers are embedded in the polymer composite material during the manufacturing of the sample. The measuring system is constructed on the basis of an adaptive interferometer. Optical fibers are part of the interferometer optical scheme. The elastic wave acting on an optical fiber changes its optical density, changing the interference pattern of the optical beam. The work of the interferometer is based on the adaptive change in the hologram, formed in the photorefractive crystal during the elastic action on the fiber. Sensitivity of fiber-optic sensors based on an adaptive interferometer allows recording acoustic emission waves. The Su-Nielsen source was used to generate the waves. The nature of the sensors, distributed in space and the anisotropy of the properties of the composite material, influenced the difference in the speed of sound in different directions and the dispersion of the velocity of the group Lamb wave. To form the signal front, the wavelet transformation was used.