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

Table 3

Modal frequencies of cantilever composite box beam: .

Mode	Natural frequency (Hz)
	Present			Reference [18]
	First flapping	1.80	1.81		1.81	1.8
Second flapping	—	11.36	11.36	11.5
First sweeping	5.67	6.20	6.20	6.5
Second sweeping	—	39.21	39.21	39.7
First torsional	37.83	37.84	37.84	37.7
Second torsional	112.90	113.01	113.01	113.3