Issue 49

V. Matveenko et alii, Frattura ed Integrità Strutturale, 49 (2019) 177-189; DOI: 10.3221/IGF-ESIS.49.19 185 For clarity, the dependences of 1 k and 2 k with respect to the plane 0.78 k  by varying   2 3 ln   ,   1 3 ln   are presented in Fig. 9. Figure 9 : Dependences of 1 k and 2 k on the components of the strain tensor. The obtained results allow us to conclude that the use of Bragg gratings written in a single-mode optical fiber provides acceptable information about the component of the strain tensor along the fiber, only in case when the sensor is located in the material zone, where this component of strain is predominant. The dependences given in Fig. 9 allow us to estimate the error in the calculation of the strain for different ratios of the strain values 1  and 2  . S IMULATION OF FOSS EMBEDDED IN PCM WITH A CAPILLARY ON THE B RAGG GRATING ne of the directions for obtaining reliable information about the strains measured by FBG sensors embedded into PCM is associated with a change in the conditions of interaction with the material of the optical fiber section with the Bragg grating. In a constructive implementation, this can be achieved by using an additional coating around the fiber in the Bragg grating zone (Fig. 10). Figure 10 : Cross-section of the sample with FOSS based on the Bragg grating and capillary. O