PSI - Issue 5

J. V. Araújo dos Santos et al. / Procedia Structural Integrity 5 (2017) 1198–1204 J. V. Araújo dos Santos et al. / Structural Integrity Procedia 00 (2017) 000 – 000

1204

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The difference in the peak is very considerable, whereas the difference in the areas is very small. This is particularly obvious for shearing amounts up to 10 mm. This indicates that the process of shearing leads to the smoothing of real values of the differences in curvatures.

4. Conclusions

The present simulations show that shearography with different shearing amounts may lead to wrong or inconsistent damage identifications. Indeed, if we use a shearing amount that is larger than the real width of damage, the peak values of the damage indicators are very different from the expected ones. A shift to the right of the damage indicators values is also observed. Although this shift varies with the shearing amount, it is independent of the stiffness reduction describing the damage. We also observe a significant increase of the attenuation of the peak values of the damage indicators with the shearing amount. The width of damage also increases with the shearing amount. In view of these conclusions, we see that it is necessary to adjust the results of the damage localization using data obtained with shearography, since these results are greatly dependent on the shearing amount considered in the measurement of the modal rotation field. A comprehensive quantitative analysis is under way, with the objective of defining general relations among shearing amount, measured modal rotation fields, and localization, intensity and type of damage.

Acknowledgements

This work was supported by FCT, through IDMEC, under LAETA, Project UID/EMS/50022/2013 and LAETA Interinstitutional Project “Advanced materials for noise reduction: modeling, optimization and experiment al validation”.

References

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