6. Summary of results

Modeling A:

Cases without taking into account the pseudo-mode: perfect agreement of the Code_Aster results with the validation sheet which indicates a tolerance of \(\text{2\%}\) on the reference values.

Cases with consideration of the pseudo-mode: significant differences with the validation sheet, up to \(\text{160\%}\); they are explained by a different calculation hypothesis (in the reference, the pseudo-mode is calculated from the value of SRO corresponding to the asymptote of the spectrum, whereas, in Code_Aster, the pseudo-mode is calculated from the value of SRO corresponding to the last frequency of the modal base in question). Note that the values obtained by*Code_Aster* are conservative compared to a calculation with a modal base that is not truncated before the cutoff frequency.

Note that models B and C containing 21 elements cause a positive mode 4 participation factor, while it is negative with modeling A.

The results of the C modeling (in particular the nodal reactions) are very sensitive to the values of the shear coefficients.