Research Article
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 | / |
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