4. B modeling

4.1. Characteristics of modeling

Plate elements DKT are used

The division is done in the following way:

We have	1	element between \({P}_{1}\) and \({P}_{2}\)
	6	elements between \({P}_{2}\) and \({P}_{3}\)
	1	element between \({P}_{3}\) and \({P}_{4}\)
	1	element between \({P}_{17}\) and \({P}_{20}\)
	10	elements along the sides parallel to \(y\) (\({P}_{4}{P}_{5}\) for example)

We pass 2 calculations:

• in the first calculation, we establish solid body connections between the lines:

• \({P}_{2}{P}_{7}\) and \({P}_{17}{P}_{22}\)

• \({P}_{3}{P}_{6}\) and \({P}_{18}{P}_{21}\)

• \({P}_{10}{P}_{15}\) and \({P}_{20}{P}_{23}\)

• \({P}_{11}{P}_{14}\) and \({P}_{19}{P}_{24}\)

via the keyword factor “LIAISON_COQUE” from the AFFE_CHAR_MECA command.

• in the second calculation, solid body connections are established between the nodes facing each other of the pairs of lines mentioned above via the keyword factor “LIAISON_SOLIDE” of the AFFE_CHAR_MECA command.

4.2. Characteristics of the mesh

Number of nodes:	242
Count of elements TRIA3:	360

4.3. Tested sizes and results

The results of the 2 calculations (one with LIAISON_COQUE, the other with LIAISON_SOLIDE) are identical. We will only mention the calculation with LIAISON_COQUE.

Clean mode order	Experimental reference	Experimental reference	% difference/finite element model	% difference/finite element model
7		± 1%	610.2	4.5
8		± 1.5%	852.4	3.2
9		± 1.7%	864.8	1.1
10		± 2%	923.9	1.4
11		± 3.6%	1110.8	—0.2
12		± 4%	1179.5	3.8

*average of 5 calculation codes

4.4. notes

Calculations made by:

CALC_MODES

OPTION = “BANDE”, CALC_FREQ =_F (FREQ = (1.,1200.)), SOLVEUR_MODAL =_F (METHODE = “TRI_DIAG”, DIM_SOUS_ESPACE = 12)

4.5. Contents of the results file

The first 6 non-zero natural frequencies (eigenvectors and modal parameters).