Vibration and Instability of Rotating Composite Thin-Walled Shafts with Internal Damping

Table 2

Modal frequencies of cantilever composite box beam: .

Mode	Natural frequency (Hz)
	Present			Reference [18]
	First flapping	3.12	3.13		3.13	3.1
Second flapping	—	19.02	19.02	19.8
First sweeping	10.80	10.81	10.81	11.0
Second sweeping	—	68.38	68.38	65.6
First torsional	37.83	37.84	37.84	37.7
Second torsional	112.91	113.01	113.01	113.3