Soundac® damping cassettes Description ® Soundac damping cassettes have been developed for the purpose of reducing the amplitude of free resonant bending waves which are set up in response to vibrations in steel or aluminium plating and constructions. The damping cassettes are suited on applications where the sheetthickness exceeds 5 mm. The cassettes can easily be welded to the construction in contrast with conventional methods of damping with a constraining layer. Application Steel < 20 mm Steel > 20 mm Aluminium The cassettes are designed to damp the resonance of first and second order bending waves on the treated construction, by means of constraining the panel motion. The reduction is effective across a broad frequency range, as a result of the damping material which is used in the cassettes. Treatment with the damping cassettes provides energy absorption even at the higher frequencies which can be born in the construction. Stock The Soundac® damping cassettes are produced according to your specification, as a result of the great variety in compositions. Please contact us for a quotation and availability in the different dimensions. Acoustics & NoiseReduction BV - Celsiusstraat 26 - 1704 RW - Heerhugowaard tel. +31 (0)72 57 27 390 - fax +31 (0)72 57 21 256 - e-mail [email protected] - website www.anr.nl Bankrekeningnr. 67.57.82.775 - K.V.K. nr. 37100240 - BTW nr. 8103.71.315.B.01

The cassettes are composed of a 1 meter long U-profile in which the viscoelastic material is cast. In this material are the 10 to 20 individual legs imbedded. These legs are welded to the structure. As the structure is subjected to vibrations the every of the motion is transmitted through the legs of the cassette which is resisted by the damping effect applied by the cast viscoelastic material. F (Hz) Measurements on 3,00 x 2,00 m aluminium, 4 mm thick, Frame 60 mm h.o.h. 600 mm with Soundac damping cassette 40.30.40.U16 Reduction acceleration level in dB When the cassettes are applied to the...

Loss factor measured on 10 mm steel 2 x 1 m Damping technique Steel and aluminium constructions of ships are highly resonant, no exceptionally great force is required to excite the structure and give rise to noise. The forces which excite the structure produce bending waves which are transmitted throughout the structure when produced by high energy sources such as propellers, main engines or auxiliary machinery. Decay of vibrations Adding to the effect of the impulse which initially excites the structure, subsequent forces add to maintain the vibration level and the rate at which the excitation...

Transmission 1. Damping of structure born sound radiated from decks, bulkheads and hillside at the receiving cabin. Practical treatment is Soundac® PUD30 and Soundac® damping cassettes. 2. Absorption of resonant vibrations around the noise source. This also means that there is less energy to be transmitted to the structure – similarly, by deadening the structure close to the source, less energy is transmitted to the structure. A practical means of achieving this objective is by the application of Soundac® damping cassettes. By such means it Is possible to obtain a reduction in noise levels in...