PSI - Issue 19

Xavier Hermite et al. / Procedia Structural Integrity 19 (2019) 130–139 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 6. Scheme of a convergence function applied to reliability assessment

If Real-Time analysis is useful for reliability demonstration, its most interesting potential is for characterization testing, which needs more samples. Taking SN Curve as an example, the test strategy should be defined in so that an approximative model parameters could be estimated with the smallest series of tests as possible. Load level to apply to the next samples could then be set to refine the parameter estimates in the lowest time as possible, still through convergence assessments. As shown in Figure 7, assumption of Basquin slope can locate SN curve with only one test. To refine this assumption, tests may be performed on at least two other stress levels; then first estimate of standard deviation can be computed with 2 others tests on a same level. To refine this estimate, new tests should be carried out at the highest stress level (to improve test duration). The last tests are performed to refine all parameters by computing a gain function.

Fig. 7. Example of a Real-Time analysis – SN Curve