4. B modeling

4.1. Characteristics of modeling

A modal calculation is carried out using the dynamic substructuring technique.

A first calculation is carried out using a projection base of the substructure composed only of static modes. For the second calculation, a base composed of normal modes and five interface modes is used.

4.2. Characteristics of the mesh

The complete structure is composed of two substructures.

The first substructure is the result of a mesh composed of 240 elements of type HEXA8.

The second substructure is obtained by translating the first substructure of \(-0.25m\).

4.3. Tested sizes and results

The first five natural frequencies of the complete structure are tested.

Identification	Reference type	Reference value
\({f}_{1}\) (base: static modes)	“NON_REGRESSION”	660.430033152 Hz
\({f}_{2}\) (base: static modes)	“NON_REGRESSION”	1030.71541399 Hz
\({f}_{3}\) (base: static modes)	“NON_REGRESSION”	1772.49983 Hz
\({f}_{4}\) (base: static modes)	“NON_REGRESSION”	2652.54751842 Hz
\({f}_{5}\) (base: static modes)	“NON_REGRESSION”	2746.67605831 Hz
\({f}_{1}\) (base: normal modes + five interface modes)	“SOURCE_EXTERNE”	660.430033153 Hz
\({f}_{2}\) (base: normal modes + five interface modes)	“SOURCE_EXTERNE”	1030.71541399 Hz
\({f}_{3}\) (base: normal modes + five interface modes)	“SOURCE_EXTERNE”	1772.49983 Hz
\({f}_{4}\) (base: normal modes + five interface modes)	“SOURCE_EXTERNE”	2652.54751842 Hz
\({f}_{5}\) (base: normal modes + five interface modes)	“SOURCE_EXTERNE”	2746.67605831 Hz