Issue 50

R. Boutelidja et alii, Frattura ed Integrità Strutturale, 50 (2019) 98-111; DOI: 10.3221/IGF-ESIS.50.10 108 Figure 13 : Damage versus O 2 concentration. Figure 14 : Probability to have a leak (case1, case12, case13 and case14). Fig. 14 regroups the leak cumulative probabilities for the treated examples. If we suppose that case1 is a reference (O 2 concentration = 0.2 ppm) one notes that when the transient regime concentration is approached (case14: O 2 concentration = 0.1 ppm) the leak probability is reduced by 12 times. Moreover, when we are below the transient regime concentration (case13: O 2 concentration = 0.01 ppm) the leak probability is reduced by 87 times. Effects of temperature change For an oxygen concentration of 0.2 ppm, Tab. 4 resumes the temperatures used to illustrate the effect of their variations. Temperatures used and cases studied Studied case Case 1-550 Case 12-560 Case 13-479 Case 14-480 Case 15-450 Temperature, (°F) 550 560 479 480 450 Table 4 : Temperatures used and cases studied Fig. 15 regroups the initiation probability curves for the 5 cases studied. Results are printed at each evaluation time for case1-550, case12-560, case13-479, case14-480 and case15-450. For weak damages (Fig. 16) the variation of temperature does not affect the initiation process (Fig. 15).