PSI - Issue 50

Valerii Matveenko et al. / Procedia Structural Integrity 50 (2023) 184–191 Valerii Matveenko, Natalia Kosheleva, Grigorii Serovaev / Structural Integrity Procedia 00 (2022) 000 – 000

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Figures 5 and 6 show graphs of strain distribution along the length of samples with different gage lengths used in measurements and the distribution of the Spectral Shift Quality parameter used to assess the quality of the measured distribution.

max( ( )

(

))

j U U U   ★ j

  

j

j

SpectralShift Quality



2

( ) 

Where ( ) j U  is the spectrum of a given data fragment in the initial unloaded state, ( ) j j U    is the spectrum for this fragment in the deformed state, and ★ is the cross-correlation operator. Spectral Shift Quality varies in the range [0,1], where 1 is the ideal correlation (Luna Technologies Inc., 2013).

Fig. 5. Strain and Spectral Shift Quality distribution along the length of the sample with round cutouts with different gage lengths used for distributed measurements.

Fig. 6. Strain and Spectral Shift Quality distribution along the length of the sample with triangular cutouts with different gage lengths used for distributed measurements.