PSI - Issue 17

H. Lopes et al. / Procedia Structural Integrity 17 (2019) 971–978 Lopes et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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constants, and the discrepancies between them. It is clear that the discrepancies are very small, thus showing that the method is reliable.

Fig. 2. Convergence of particle swarm, pattern search and genetic algorithms.

Table 1. Experimental and numerical frequencies and their relative discrepancies.

Relative discrepancy [%]

Experimental frequency [Hz])

Numerical frequency [Hz]

Mode

ͳ ͻ͹Ǥ͹ͷͲ ͳͷͳǤ͹ͷͲ ʹ͹ͲǤʹͷͲ ͵ʹͶǤ͹ͷͲ ͷ͵ͲǤʹͷͲ ͷͶͳǤͷͲͲ ͺͳͻǤ͹ͷͲ ͺ ͺ͹ͷǤ͹ͷͲ ͳͲ ͳͳͳ͵Ǥ͹ͷͲ ʹ ͵ Ͷ ͷ ͸ ͹

ͻ͹Ǥͺ͹ͳ ͲǤͳʹ ͳͷͳǤʹͶͻ – ͲǤ͵͵ ʹ͹ͲǤͳ͹ͺ – ͲǤͲ͵ ͵ʹͶǤ͸͸ͷ – ͲǤ 03 ͷ͵ͲǤʹͷ ͲǤͲͲ ͷͶͳǤͲͺ͵ – ͲǤͲͺ ͺͳͺǤ͹ʹͷ – ͲǤͳ͵ ͺ͹͸ǤͳͺͶ ͲǤͲͷ

ͻ ͳͲ͸ͺǤͲͲͲ ͳͲ͸͹Ǥͺͳͺ ͳͳͳ͵Ǥ͹ͷ ͲǤͲͲ ͳͳ ͳͳ͹ͲǤ͹ͷͲ ͳͳ͹ͲǤ͹ͷͶ ͲǤͲͲ ͳʹ ͳʹ͵ͶǤ͹ͷͲ ͳʹ͵͸ǤͶ͸͸ ͲǤͳͶ ͳ͵ ͳ͵ʹʹǤʹͷͲ ͳ͵ʹʹǤʹͷ ͲǤͲͲ ͳͶ ͳͶͷ͵ǤͷͲͲ ͳͶͷͶǤͷͶͺ ͲǤͲ͹ The modal displacements rotations in the and directions corresponding to the first, ninth, and fourteenth natural frequencies computed with the finite element model are shown in Figure 3. – ͲǤͲʹ