PSI - Issue 47

Oleg Naimark et al. / Procedia Structural Integrity 47 (2023) 782–788 / Structural Integrity Procedia 00 (2019) 000–000

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acquired from the optical fiber discerns the damage zones located in epoxy matrix or brittle carbon fabric, or the interfaces in composite materials.

Figure 1. Scheme of the experiment on fiber-optic recording

Three channels were combined for the recording with sampling frequency 2 MHz: the signals on the first and second channels were obtained using piezoelectric transducers, and the third channel used a fiber optic

sensor. зкузкупзкузкуп Specimen preparation

Preparation of CFRP samples was preceeded to acoustic signal recording experiments. С arbon fiber reinforced plastic (CFRP) samples were made using prepreg technology and autoclave molding from 10 layers of Porcher 3692 carbon fabric and an epoxy matrix. Fiber-optic lines with a diameter of 0.2 mm were placed between 5 and 6 layers of CFRP. The plate with dimensions of 730 x 500 mm was made with 5 embedded fiber-optic lines, Fig. 2.

Figure 2. Technology stage of composite manufacturing and the sample with optical fibers

The technological process of embedding fiber-optic sensor (FOS) elements into a composite material included the following main operations: (i) Cutting the reinforcing material on the Zund G3 L-2500 plotter and laying out the required number of layers of reinforcing material on the technological equipment; (ii) Laying fiber optic sensors between layers of reinforcing material according to a predetermined scheme for samples cutting; (iii) Assembly of the technological package for material pre-compression; (iv) Technological support for protecting the outputs of FOSs from temperature and pressure;