The ICA is the world’s largest and most important conference for all fields of acoustics. It is organized every three years and this time included more than 1500 abstracts presented to over 1700 participants. The main purpose of the ICA is to promote international development and collaboration in all fields of acoustics including research, development, education, and standardization.
The session for acoustics of ships and offshore structures was opened by Dr. Lothar Kurtze, the acoustic expert at Geislinger, with a presentation about an “Innovative solution to reduce the transfer of structure-borne noise in couplings”. Geislinger presented that modern couplings for ships, and especially for mega yachts, have to fulﬁll various tasks. Located between the gearbox and the propeller shaft, they minimize the transfer of structure-borne noise while transmitting high torque levels. In addition, they must resist high misalignments due to very softly mounted frames of the ship’s engine and gearbox.
To fulﬁll these partly contradictory demands, innovative approaches are essential. Therefore, Geislinger has developed the Geislinger Silenco® Coupling which is made from a combination of glass and carbon ﬁbers, elastomer layers, and steel.
After the design phase, couplings like the Geislinger Silenco® are tested on Geislinger’s unique acoustic test bed. Figure 2 shows the typical noise reduction of a Geislinger Silenco® coupling for a medium speed engine. Here, the structure borne noise was measured directly in front of (black) and behind the coupling (red) on the test rig using real engine noise as an input-signal.
Validation on the Geislinger Test bed is usually followed by tests with real propulsion systems like Advanced Electric Drives in the 4 MW-range. The presentation showed how the new couplings have been successfully validated during the vessel’s sea trials.
It has been of particular interest to the audience that Geislinger’s couplings can signiﬁcantly reduce the noise radiation into a ship’s structure as well as into the ocean. Measurements have proven that they are able to fulfill the requirements for an ultra-silent propulsion – this is also a benefit to the environment.
The complex field of the acoustic optimization will also be presented during the Torsional Vibration Symposium, May 13-15, 2020 in Salzburg. The full paper is available for download here.
Source: Proceedings of the 23rd International Congress on Acoustics, integrating 4th EAA Euroregio 2019, Aachen