PSI - Issue 68

Martin Nesládek et al. / Procedia Structural Integrity 68 (2025) 527–533

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Martin Nesládek et al. / Structural Integrity Procedia 00 (2025) 000–000

b

a

&' = 210 &' = 158

SH tests were conducted using an OPTRIS PI450i thermal camera with a resolution of 382x288 pixels. The specimens and pads were coated with black paint with a high declared emissivity % = 0.963. SH data, presented as stabilized temperature increases in the specimen's fatigue process zone for two fretting pad configurations, are shown in Fig. 5. The evaluation of the fatigue limit using the Matušů method is provided for reference. Note that the horizontal axis represents stress amplitude normalized by the conventional fretting fatigue limit. Thus, a value of 1.0 indicates the normalized stress level at the conventional fretting fatigue limit, which the SH methods should locate. Note that the Luong’s method provides similar output for the single-surface pads while for the bridge pads it results in estimate, which is 13 % lower than the conventional &' . Fig. 4. (a) Fretting fatigue test setup. (b) Conventional S-N curves for the two tested specimen-pad configurations. Blue color represents data for single-surface pads and the green is for the bridge pads. b

a

Fig. 5. SH data and fatigue limit evaluation by using the Matušů method. (a) Single-surface pads. (b) Bridge pads.