8. F modeling

8.1. Characteristics of modeling

TUYAU and TUYAU_6M.

The discretized geometry on the axis of the ring is shown above. The elements TUYAU and TUYAU_6M are 3-knot meshes of type SEG3 representing the axis of the ring. The number of nodes on the axis is 5.

8.2. Characteristics of the mesh

Number of knots: 5

Number of meshes and type: 2 SEG3

8.3. Tested values

(Frequencies in hertz)

Mode	Reference	Aster **** TUYAU **	% difference	Aster** TUYAU_6M **	% difference
ovalization	210.55 210.55	209.02 209.02	—0.72 —0.72	209.02 209.02	—0.72 —0.72
trifoliate	587.92 587.92	591.00 591.00	0.52 0.52	591.00 591.00	0.52 0.52
off plan	205.89 205.89 588.88 588.88	259.74 259.74 649.57 649.57	26.15 26.15 10.31 10.31	259.74 259.74 649.57 649.57	26.15 26.15 10.31 10.31

8.4. notes

The models in TUYAU (limited by construction to 3 Fourier modes) and TUYAU_6M do not allow the out-of-plane modes to be represented correctly. On the other hand, they provide the same results on plane modes, close to the reference.