Issue 60

N. Zekriti et alii, Frattura ed Integrità Strutturale, 60 (2022) 488-503; DOI: 10.3221/IGF-ESIS.60.33

Empirical model Empirical models play an important role in ensuring the order and understanding of complex interrelationships between variables. By removing measurement errors, they enhance the ability to develop hypotheses and explain behaviors based on measured results. We used a model fit that was consistent with our results to investigate the crack propagation velocity. Fig. 11 shows the evolution of crack length over time for each crosshead speed, demonstrating an exponential increase that can be expressed using an exponential function Eqn. 19. A good fitting with a correlation factor (R2>0.9) was obtained for all curves. Tab. 4 Contains the parameters α , β , and R2 of the following equation:

     ( 1) t a e

(19)

Figure 11: Model Crack length as a function of life fraction.

Crosshead speed (mm/min)

α

β

R2

5

0.29

6.09

0.99

10

0.37

3.61

0.96

100

0.97

2.92

0.98

Table 4: Parameters of the exponential model.

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