Frequency Equations for the In-Plane Vibration of Circular Annular Disks

Table 5

Frequency parameters of in-plane vibration of an annular disk with “Free-Free” conditions.

Radius ratio (β)	𝑛=1		𝑛=2		𝑛=3		𝑛=4
	Reference [15]	present study	Reference [15]	Present study	Reference [15]	Present study	Reference [15]	Present study
0.2	1.652	1.651	1.110	1.110	2.071	2.071	2.767	2.766
	3.842	3.842	2.403	2.402	3.401	3.400	4.389	4.388
0.4	1.683	1.682	0.721	0.721	1.618	1.619	2.482	2.482
	4.044	4.044	2.451	2.450	3.346	3.346	4.227	4.226