Research on the Vibration Characteristics of a Compounded Periodic Strut Used for Helicopter Cabin Noise Reduction

Table 2

Main geometric dimension.

Structure	Material	Length; (mm)	External diameter (mm)	Inner diameter (mm)
Upper cylinder	Rubber	30	70	35
	Metal	22	70	35
Lower cylinder	Rubber	30	70	/
	Metal	22	70	/