PSI - Issue 47

Artur Mugatarov et al. / Procedia Structural Integrity 47 (2023) 654–659 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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3.4. Temperature influence The influence of the temperature on the fatigue sensitivity (samples groups 1 and 4) was studied (Lobanov and Staroverov (2019)). Obtained model parameters are κ =8.6281, λ =0.12048. Figure 4 shows the obtained fatigue sensitivity curves and the corresponding damage function derivatives. It was found out that temperature growth leads to approximation function parameters change: growth of the shape factor by 3 times, decrease of the scale factor by 2 times. At the elevated temperature of preliminary cyclic exposure, an earlier onset, a longer duration, and a late completion of the stabilization stage are observed. There is also a significant decrease in the damage value growth rate by 3.5 times. The influence of the layout on the fatigue sensitivity (samples groups 1, 5 and 6) was studied (Wildemann et al. (2019, 2021)). Obtained model parameters are κ =5.6521, λ =0.06383 for the layout [±45] n , and κ =3.0168, λ =0.19204 for the layout [0/±30/90/±60] n . Figure 5 shows the obtained fatigue sensitivity curves and the corresponding damage function derivatives. It can be noted that for the layout [±45] n there is practically no decrease in strength characteristics, the stabilization stage takes more than 95% of the fatigue life. For the layouts [0/±30/90/±60] n and [0/90] n , the obtained model parameters are close; for the first of the schemes, the longer stabilization stage and the slower decrease in the composite strength are observed. 3.5. Layout influence

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T=120°C T=22°C

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0.4 ω ' B 0.6

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Fig. 4. Temperature influence: fatigue sensitivity curves (left side) and damage value derivative (right side)

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[±45]n [0/90]n [0/±30/90/±60]n

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Fig. 5. Layout influence: fatigue sensitivity curves (left side) and damage value derivative (right side)