PSI - Issue 37

T. Oliveira et al. / Procedia Structural Integrity 37 (2022) 698–705 T. Oliveira et al. / Structural Integrity Procedia 00 (2022) 00 –000

705

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Fig. 12. Detection quality according to noise level.

Figure 12 shows a clear correlation between derivative order and resilience to noise in the measurements, where the first derivative leads to a lower quality damage detection, but is also much more immune to the noise. On the other hand, it is observed that the quality of damage detection increases with the order of the derivative, with the cost of also being less immune to the noise.

4. Conclusions

A new damage index is proposed for multiple damage localization in laminated composite plate, based on the plate mode shapes and spatial derivatives. The results show a better performance of the proposed SFD damage index in relation to other damage index found in the literature. As expected, the detectability of damage increases with the order of the derivative. The introduction of di ff erent noise levels allowed us to observe a decrease in the detection quality, having defined the threshold of µ = 0 . 85. On the other hand, it was observed an increase in the damage detection quality with the order of the modal derivative and a lower noise immunity.

References

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