PSI - Issue 75

Marco Bonato et al. / Procedia Structural Integrity 75 (2025) 677–690 / Structural Integrity Procedia (2025)

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subjected to vibrations in the plane normal direction (vertical direction, Z axis). A total of 16 specimens were tested, mounted on the fixture by groups of 4 samples. The prototype specimens were characterized by the research of the resonance frequency. The structural response was monitored by one accelerometer attached to the end of the part, where the displacement and acceleration are the highest. Details of the experimental test set-up are illustrated in Figure 5. The post-processing of the measured response during one sinusoidal sweep (from 5 to 1000 Hz, amplitude 1 g) permits to calculate the frequency of the first mode (236 Hz) and the damping of the system (~1%).

Figure 5:Vibration prototypes mounted on the test fixture.

For the fatigue tests, the prototypes were subjected to the sweep-sine-on-random vibration fatigue tests, until the appearance of the crack initiation point (see Figure 6). The intensity of this loading spectrum was adjusted to give rise to fatigue failure in the coupons within a reasonable period (estimated, according to the FEA simulations, in average of 1 hour).