PSI - Issue 37

V.P. Matveenko et al. / Procedia Structural Integrity 37 (2022) 508–516 Matveenko V.P., Kosheleva N.A., Serovaev G.S./ Structural Integrity Procedia 00 (2021) 000 – 000

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Fig.5. Evolution of FOS readings and reflected spectra at different points in time in a liquid plastic sample.

Fig.6. Liquid plastic sample with embedded FOS.

Due to a fast chemical reaction, a rapidly increasing temperature, and a complex stress state in embedded FOS, it can be noted that the reflected spectrum becomes highly distorted (Fig. 5, position 6 ) and doesn’t have a pronounced resonance peak . Such reflected spectrum doesn’t allow to obtain reliable strain value based on the experimental data . Finished sample is shown in Fig. 6.

2.4. Embedment of FOS into 3D printed samples

The process of creating a cube-shaped sample by 3D printing with embedded optical fiber can be divided into four stages: 1) printing the material up to the layer where the optical fiber should be located, 2) stopping printing process for positioning and laying the optical fiber with inscribed FBG sensor (Fig. 7), 3) attachment of optical fiber to the host material, 4) resuming printing until the sample is ready. Cubic samples with an embedded FOS were made of Polylactic acid (PLA) (Fig. 8) and High Impact Polystyrene (HIPS) (Fig. 9), using a Creality Ender 3 V2 3D printer.

Fig.7. Embedding process of FOS during 3D printing.

Fig.8. PLA sample with embedded FOS.

Fig.9 HIPS sample with embedded FOS.

3. Samples testing Manufactured samples (Fig. 10) with embedded FOSs based on Bragg gratings were tested for compression using a Zwick Z100 / SN5A universal testing machine.