PSI - Issue 24

Alessandro Castriota et al. / Procedia Structural Integrity 24 (2019) 279–288 A. Castriota et al. / Structural Integrity Procedia 00 (2019) 000 – 000

287 9

(a)

(b)

Fig. 10. Numerical buckling mode; (a) intact panel; (b) damaged panel

6. Conclusions

The buckling behavior of a CFRP aeronautical panel with longitudinal (five stringer) and transverse (two ribs) reinforcements was studied in two different structural configurations of intact panel and panel with a simulated damage by a cut . An experimental analysis was carried out on the damaged panel, allowing a validation of the numerical model with respect to the linear static behavior. The comparison of the axial stiffness showed a percentage variation of 9%. The simulations for calculating the deformation state of the component and for calculating the first load and the first buckling mode of the panel were carried out, for each of the structural configurations. It has been shown that the intact panel exhibits an axial stiffness slightly higher than in the case of a panel with the saw-cut. Finally, a comparison was made between the first eigenvalue and the buckling mode of both architectures considered. The result was that the first eigenvalue of buckling of the intact panel is slightly higher than the first eigenvalue of the damaged panel, with a percentage difference of 3.51%; the first mode of buckling of the intact panel is anti symmetrical while for the damaged panel it is symmetrical. In conclusion, the presence of a relevant damage, simulated by a large transversal cut, does not influence particularly the buckling behavior of a CFRP panel reinforced with stringer and ribs. The good correspondence between the numerical and experimental values gives a good degree of confidence on what is obtained numerically, even if the model did not contain the interlaminar interaction mechanisms and only a linear buckling analysis was conducted.

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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