Vibration reduction on bunk-beds

Status:

completed 12/1994

Aims:

The lightweight construction of modern trading vessels and ferry boats leads to an increased transmission of vibration inside the hull. Besides, the crew's cabins are nowadays situated closer to the engine room to create a large and undivided cargo space. Consequently, the bunk-beds are equally subject to increased vibration. To limit the whole- body vibration the crew is exposed to, elastic bunk bearings were expected to counterbalance the increase in vibration. Apart from the desired reduction in the vertical vibration direction, a negative effect could be noticed for the horizontal direction. The project was aimed to avoid such negative results without limiting the obtained vibration reduction in the vertical direction. The project was initated by the institution for statutory accident insurance and prevention in the maritime industries.

Activities/Methods:

A variety of excitation signals - registered by Deutscher Loyd and BIA itself - were used to conduct laboratory measurements on a servo-hydraulic vibrator in the Berufsgenossenschaftliches Institut für Arbeitssicherheit - BIA. The results were validated under real-life conditions on an ocean-going vessel.

Results:

The damping properties of interior spring mattresses are clearly superior to those of standard foam rubber mattresses and hardly inferior to the vibration reduction achieved by means of pneumatic spring bearings of the bunks. They are not prone to undesirable sympathetic vibration as a result of a rough and heavy sea. Depending on the case, especially designed cushions may strengthen the mattress's damping effect.

Publications:

Interner Bericht an die See-Berufsgenossenschaft

Further informations:

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