PSI - Issue 12

A. Castriota et al. / Procedia Structural Integrity 12 (2018) 71–81

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Castriota et al. / Structural Integrity Procedia 00 (2018) 000 – 000

repaired zone is compatible with the maximum failure load used in design phase, confirming the reliability of the repair process. A comparison was made between the experimental and numerical bending stiffness. It has been found that the experimental stiffness is greater than 7.71% with respect to the numerical stiffness. A final static test was performed to evaluate the maximum failure load of the spar. A normalized breaking load of 1.84 times the expected normalized failure load was achieved. The failure occurred in the compressed zone of the spar for delamination of the laminas that made up the spar cap. In conclusion, the repair has not played any important role in the modification of the structural properties of the spar, not resulting in significant reductions in flexural fatigue strength and residual strength. Moreover, even if the numerical model did not contain the repair and did not consider the interlaminar interactions mechanism, the difference in terms of stiffness with the experimental reality is to be considered acceptable.

Fig. 11. Normalized load – deflection curve for Step 3

a

b

Fig. 12. Failure of the spar cap to normalized failure load of Step 3

Acknowledgements This work has been financially supported by the project PON03PE_00067_2 Defect, damage and repair techniques in the manufacturing process of large composite structures (DITECO).

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