PSI - Issue 75

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

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/ Structural Integrity Procedia (2025)

Figure 4: 3D visualization of variable distribution after LHS triage (first FEA iteration) In a second run of FEA simulations, the LHS is left unchanged. Only one setting on the nCode DesignLife software has been modified: the surface treatment is now moved from the default value (3.5 micron polishing) to “machined”, to better represent the prototyping process of the physical specimens. The resulting test plan included 20 simulations runs. A third iteration of the FEA simulation came with a major constraint on the Basquin’s b parameter. The reasoning behind is that the experiential variability of this parameter is quite small. As for iteration #2 a, additional parameter, the surface roughnes s, is considered as “machined”. The resulting test plan included 30 simulations runs ● Damping : uniform distribution, [0.9 ; 1.2] ● Intercept/UTS: uniform distribution, [4.7 ; 5.1 ] ● Surface Roughness: Machined In a final run of simulations (the fourth iteration), the Damping and Intercept/UTS ratio are further constrained to match the statistical scatter (from measurements acquired during the characterization) of the material considered after laboratory analysis and the resonance search analysis. The resulting test plan included 30 simulations runs. ● Damping : uniform distribution, [0.95 ; 1.15] ● Intercept/UTS: uniform distribution, [4.7 ; 4.8 ] ● Surface Roughness: Machined The characterized material data from the fourth iteration was then applied to the simplified sine and random signals in subsequent FEA analyses - results are not presented here. 2.4. Vibration Fatigue Tests on Physical Prototypes The test case chosen uses test prototypes, of different geometry to those used for the material characterization, with such a geometry to show only one resonance within the frequency range of the applied vibration signal. The coupons were clamped at one end to a vibration shaker table after being mounted on a fixture, so that they might be