Bae Systems, Inc.

Gec-marconi Limited

Bae Systems Electronics Limited

Frederick A Johnson

Malcolm A Swinbanks

Stephen Daley

Christopher F King

David C Sexton

A support for machinery, and for isolating vibration from the machinery, includes a plurality of mounts, each mount including an elastomeric block for completely supporting the static load of the machinery, and an active isolation element including inertial shakers arranged to effect a zero stiffness of the mount to excited structural resonances over a desired frequency band above the mount resonant frequency, and to modify the transmission of out of balance forces to the hull. A control system coupled to the inertial shakers includes a controller configured to apply damping force signals, such as to dampen structural resonances, to inhibit the onset of resonant vibration.

Vibration isolation

A support for machinery, and for isolating vibration from the machinery, comprises a plurality of mounts, each mount comprising an elastomeric block for completely supporting the static load of the machinery, and active isolation means comprising inertial shakers arranged to maintain essentially a zero stiffness of the mount to excited structural resonances over a desired frequency band above said mount resonant frequency, and to modify the transmission of out of balance forces to the hull. A control system coupled to the inertial shakers includes a means for applying damping force signals, such as to dampen structural resonances, to inhibit the onset of resonant vibration.

A hull () has mounted thereon a number of accelerometers () arranged to provide a data signal corresponding to movement or vibration of the hull () to which each is fixed. The hull () and/or a thrust block () has mounted thereon a number of mass dampers () that are controlled by a detector () arranged between the accelerometers () and mass dampers (). The detector () calculates from the data signal generated by the accelerometers () different modes of resonance so as to determine the onset of the excitation of a particular resonance mode and controls the mass dampers () so as to generate forces to selectively dampen the resonance mode.

Arrangement for damping of structural resonance

A support actuatorcomprises an electro-magnethaving an input current, provided through a current controller, and which is arranged to generate a magnetic fieldhaving a variable intensity proportional to a variable currentsupplied by the controller. The intensity of the fieldis controlled to ensure that the magnetis separated from a support armaturearranged to carry a load by an operational gap A load cellis connected between the armatureand a mounting positionfor the armature. The cellproduces a control signalrepresenting variations in force generated by the magnetic fieldwhich acts on the load, and the signalis fed backward, along a feedback control pathto the controllerso as to control the variable currentsuch that it is made substantially equal to a gain demand force D.

Control of electro-magnets

A vessel comprises a cylindrical hull (10) containing a structure (11) carrying machinery (M) supported from the hull (10) by electromagnetic levitation means (12-17) that maintain electromagnetic forces between flux gaps (24) which are arranged to extend radially of the adjacent hull (10) curvature and longitudinally of the hull (10). In this manner, the transmission of noise from the machinery (M) to the hull (10) is obviated so as to reduce the detectable acoustic signal emitted by the vessel and furthermore, radial expansion or contraction of the hull (10) is prevented from mechanical transmission to the structure (11) via the levitation means (12-17).

Mounting of machinery within a vessel

A submarine is provided with a large number of individual fins, some of which are arranged to create a 'slot' effect between them. The fins are controlled in a way which is dependent on which of them may be in service at a particular time so that manoeuvreability is substantially unaffected by damage to a limited number of them.

Underwater vehicle

The engine and other machinery within a marine vessel is mounted on a raft which is relatively flimsy compared with conventional constructions. The raft is supported by electromagnets, the current to which is controlled so as to avoid vibration and flexing which would otherwise take place and so as to reduce transmission of vibration to the hull and other parts of the ship.

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Sevenoaks, United Kingdom

Frederick A Johnson