The direct and cross FRFs for the two degree of freedom system shown in Fig. P6.2a are provided in Figs. P6.2b and P6.2c.

Fig. P6.2a Two degree of freedom spring-mass-damper system under forced vibration.

Fig. P6.2b Direct FRF \(X_{2} / F_{2}\)

Fig. P6.2c Cross FRF \(X_{1} / F_{2}\)

(a) If the modal damping ratios are \(\zeta_{q 1}=0.01\) and \(\zeta_{q 2}=0.016\), determine the modal stiffness values \(k_{q 1}\) and \(k_{q 2}(\mathrm{~N} / \mathrm{m})\) by peak picking.
(b) Determine the mode shapes by peak picking.

Transcribed Image Text:

ki C1 X1 mi k2 C2 x2 m2 Freicot