GB2468488A

GB2468488A - Open Squeeze Film Damping System

Info

Publication number: GB2468488A
Application number: GB0904020A
Authority: GB
Inventors: Shaoming Yoa
Original assignee: University of Sheffield
Current assignee: University of Sheffield
Priority date: 2009-03-09
Filing date: 2009-03-09
Publication date: 2010-09-15
Also published as: GB0904020D0; WO2010103313A1

Abstract

A damping system 10 for damping vibrations in a component 16 during the machining comprises a support 12 having an operating surface 14, a reservoir 18 in fluid communication with the operating surface, a squeeze film damping (SFD) fluid 20 disposed on the operating surface 14 such it flows into and out of the reservoir in response to vibrations in the component 16, damping the vibrations. Due to the surface tension of the fluid no sealing is necessary, creating an open system. Forces caused by the vibration of the component may move the fluid into and out of the reservoir so no power or heat source is necessary and the component need not be pre-loaded. A damping factor of at least 1.0 may be achieved. Plural operating surfaces, supports and reservoirs may be used (figures 18-26). The fluid may be re-usable or recyclable and free of harmful or hazardous chemicals, and may be water based, oil based or a colloid. The reservoir may be formed by intersecting grooves in the operating surface and pressure equalization holes (24, figure 5) may be provided at the intersections. The operating surface may be planar, annular or otherwise shaped to be complementary to the component. The fluid 20 may separate the component from the operating surface 14 by a gap G and from the base of the grooves 18 by a gap S, which may be less than 1 mm.

Description

I

Damping System (0001] This invention relates to a damping system, and more specifically relates to a damping system for damping the vibrations that arise in a component during the machining of that component.

BACKGROUND

(0002] In the aeronautical and astronautical industries, aircraft and spacecraft components are commonly produced in shell form to keep their mass to a minimum. Examples of shell-like components include leading edges, casings, blades, vanes and rotor disks. When machining shell components, it is found that large vibrations are produced which can be detrimental to the accuracy of the machining process or the shell components themselves.

(0003] GB-A-2447278 (The University of Sheffield) describes an adaptive design of fixture for providing support and rigidity to thin-walled shell/cylindrical components during machining.

However, many shell components (aerofoils, for example) are not cylindrical, or indeed symmetrical and would not benefit from the fixture described in GB-A-2447278.

(0004] Rubber dampers offer an alternative damping system and are used extensively in vibration control. Nevertheless, the vibrations created during shell machining are of the order of tens of microns and so, due to component tolerance and surface finishing, a large preload is required to eliminate any gaps between the rubber damper and the shell component. For shell components, the application of a preload causes deformation of the shell structure and is therefore undesirable. Notwithstanding the problems associated with preloading the component, in many cases rubber damping systems are only capable of providing a damping factor of up to around 0.3, which is insufficient for the levels of vibration produced in shell machining.

[0005] An alternative damping arrangement uses wax as a damping medium. This damping arrangement is often used in the engine industry when machining the ends of shell components since it provides both clamping and damping. In order to conform to the profile of the component surface, the wax is heated to melt it and cast it over the desired area. This process requires heating equipment and, in some cases, large amounts of energy to cast the wax. In addition, the wax must be safely disposed of (if it is not to be used again) and volatile chemicals that result from melting the wax must be carefully controlled and monitored.

[0006] There is therefore a need for a damping technique to damp vibrations produced during -shell machining that is both more cost effective and environmentally friendlier than current methods.

(0007] A further example of a known damping technique is squeeze film damping (SFD). This technique has been extensively used in rotor dynamics to control vibration of the rotor. The documents US 4,781,077 (EI-Sahfei), US-B-6,239,943 (Jennings et al.), US-A-2008/0240632 (McMurray et al.), US-A-2002/01 36473 (Mollmann) and US-A-2007/0086685 (Kiusman et al.) all disclose applications of squeeze film damping. In particular, in each of the cited documents, a squeeze film is contained between two seals and two moveable surfaces. The squeeze film acts to suppress relative movements of the two moveable surfaces thereby reducing the level of vibration.

[0008] In another example, US-A-2008/0292234 (Wada et al.) describes a squeeze film damper for a bearing where the damping medium is contained by a flexible foil. Also, in US 4,952,076 (Wiley, Ill et al.) a squeeze film damper is formed by the combination of 0-ring grooves and a flexible curved beam with nibs.

[0009] Finally, US-A-5244285 (Hagstedt et al.) and W0-A-03/087599 (Honeywell International Inc.) describe squeeze film dampers where oil is supplied to the damper from an external source. In particular, in US-A-5244285 (Hagstedt et al.), pressurised oil is supplied through channels that creates a lifting force to produce damper clearance.

(0010] It is an object of the present invention to provide an improved damping system that is suitable for effectively damping vibrations in a shell component during shell machining and overcomes the problems associated with the prior art discussed above. -.

BRIEF SUMMARY OF THE DISCLOSURE

(0011] In accordance with the present invention there is provided a damping system for damping vibrations in a component during the machining of the component, said system comprising at least one support having at least one operating surface; at least one reservoir in fluid communication with said at least one operating surface; and a squeeze film of a damping fluid disposed on said at least one operating surface wherein the damping fluid is adapted to flow into and out of said at least one reservoir in response to vibrations in a component supported on said squeeze film and damp vibrations in the component.

(0012] This arrangement allows the damping fluid to be held between the operating surface of the support and the component that is to be machined, and thereby provide damping to the moving component. Since the damping fluid is generally held by its own surface tension around the operating surface, the reservoir and the surface of the component, the system negates the requirement of sealing the damping medium, in contrast to many prior art arrangements.

(0013] As the component moves towards the operating surface (due to vibration) the damping fluid will be compressed and move into the reservoir(s). As the damping fluid is compressed it provides a force to the component that retards its motion towards the operating surface. As the component moves away from the operating surface (due to vibration) the damping fluid will be drawn out of the reservoir(s). The damping fluid applies a viscous force and an inertia force on the moving component that retards its motion away from the operating surface. The overall effect is that oscillations in a component are damped by the system such that the risk of component damage from the oscillations is reduced and the accuracy of the machining process is improved.

(0014] In addition, the system is arranged such that the damping fluid automatically moves in and out of the reservoir(s) in response to oscillations in the component. Therefore, the system is capable of operating without any external power source to pump the damping fluid to a desired location, for instance.

(0015] The damping fluid also provides a close-tolerance damping medium negating the requirement of preloading the component. The risk of component damage through preloading is therefore reduced through use of the present invention. The close tolerance arrangement of the present invention means that increased damping factors are achievable when compared to prior art systems. In preferable embodiments, a damping factor of at least 1.0 is achieved.

[0016] The present invention provides a flexible arrangement that may be tailored to specific applications without departing from the scope of the invention. In particular, any number of operating surfaces and/or supports may be employed where each operating surface is configured to correspond to the contours of the component that is to be machined. This flexibility allows the present invention to provide the close-tolerance damping discussed above to any free form shaped component including many shell structures such as aerofoils. In addition, the flexibility of the system means that the supports and/or operating surfaces may be arranged to clamp the component along any given axis during machining. Whilst it may not always be necessary to clamp the component, it may be preferable to do so in some circumstances.

[0017] In one preferable embodiment, said at least one operating surface is adapted to receive said film for supporting a component along one surface of said component. In an alternative preferable embodiment, the system comprises at least two operating surfaces, wherein said at least two operating surfaces are adapted to receive said film for supporting a component along more than one surface of said component. In other embodiments, the damping system may comprise at least two supports.

[0018] Further to the technical effectiveness of the present invention, it offers a user friendly system for damping vibrations in a component during machining of that component. The damping fluid is preferably re-usable or recyclable and is preferably free of any harmful chemicals allowing easy and safe handling and disposal.

[0019] In one preferable embodiment, the damping fluid is a water based liquid. In an alternative preferable embodiment, the damping fluid is an oil based liquid. In a further alternative preferable embodiment, the damping fluid is a colloid. The present invention is capable of providing damping without the need to alter the temperature of the damping fluid and in preferable embodiments, negates the requirement of heating apparatus, thereby reducing the complexity of the system and the energy consumption in comparison to some prior art devices. These factors also improve the cost efficiency of the present invention when

compared to some prior art devices.

(0020] Preferably the system further comprises pressure equalisation holes that provide fluid communication between said at least one reservoir and the external environment. The holes serve to balance the pressure in said at least one reservoir with the external environment such that the damping fluid can flow efficiently in response to the oscillating component.

[0021] In a preferable embodiment, the at least one reservoir is a plurality of grooves in said at least one operating surface and said one or more holes is or are preferably located in said grooves. The grooves create distinct damping segments on the operating surface effectively independent of one another The grooves substantially prevent the damping fluid from flowing across the operating surface and behaving like one large damping medium. The grooves can therefore be designed so that certain segments are larger than others where each segment possesses specific damping properties. The precise arrangement of grooves can therefore be tailored to give a specific damping profile for a particular component.

[0022] Preferably said grooves intersect one another at intersection points and said one or more holes is or are located at said intersection points. Each hole can then serve more than one damping segment.

(0023] In a further preferable embodiment, the grooves comprise one or more boundary grooves around edges of said at least one operating surface and one or more isolating grooves that traverse said at least one operating surface between said edges. The boundary grooves then define the limits of the operating surface and prevent the damping fluid from flowing beyond and restrict the inward flow of air or unwanted fluid.

(0024] In one preferable embodiment, said at least one operating surface is planar. Such an operating surface is particularly suitable for use with planar components. In another preferable embodiment, said at least one operating surface is annular and is particularly suitable for use with annular components.

[0025] Therefore, the present invention provides an improved damping system that is particularly suitable for damping vibration in a component during machining of that component, and overcomes the problems associated with the prior art discussed above. In particular, the system is capable of being operated without a sealing device (i.e. as an "open" system), without an external power source (i.e. a self contained system), without the need to preload the component, and without the requirement of additional heating equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which: Figure 1 is a sectional side view of a damping system according to the invention and corresponds to sections I-I of Figures 3-16, as a component moves towards a support; Figure 2 is a sectional side view of the damping system of Figure 1, as the component moves away from the support; Figure 3 is a top down view of a rectangular support comprising boundary grooves and an operating surface; Figure 4 is a top down view of a rectangular support comprising boundary grooves, isolating grooves, an operating surface and a pressure equalisation hole; Figure 5 is a top down view of an alternative embodiment of the support of Figure 4; Figure 6 is a top down view of a circular support comprising a boundary groove and an operating surface; Figure 7 is a top down view of a circular support comprising boundary grooves, isolating grooves, operating surfaces and pressure equalisation holes; Figure 8 is a top down view of an alternative embodiment of the support of Figure 7; Figures 9 to 16 are top down views of alternative embodiments of supports according to Figures 3 to 8; Figure 17 is a sectional side view of a damping system according to the invention that shows a component being supported on one side by a single support; Figure 18 shows an alternative embodiment of the system of Figure 17 where a component is supported on two sides by two supports; Figure 19 shows an alternative embodiment of the system of Figure 17 where a component is supported on one side by a plurality of supports; Figure 20 shows an alternative embodiment of the system of Figure 17 where a component is supported on two sides by a plurality of supports; Figure 21 shows an alternative embodiment of the system of Figure 17 where a component is supported on two sides by a single support; Figure 22 shows an alternative embodiment of the system of Figure 17 where a component is supported on two sides by a first support and on a further two sides by a second support; Figure 23 shows an alternative embodiment of the system of Figure 17 where a corn ponent is supported on three sides by a single support; Figure 24 shows an alternative embodiment of the system of Figure 17 where a component is supported on three sides by a first support and on a further three sides by a second support; Figure 25 shows an alternative embodiment of the system of Figure 17 where a component is supported on three sides by two supports, each support having two operating surfaces; Figure 26 shows an alternative embodiment of the system of Figure 17 where a component is supported on three sides by a first pair of supports, where each support of the first pair has two operating surfaces, and on a further three sides by a second pair of supports, where each support of the second pair has two operating surfaces; Figure 27 shows a perspective view of damping system according to the invention comprising an annular support and an annular component; Figure 28 shows an alternative embodiment of the system of Figure 27 where the component is supported on two sides by two supports; and Figures 29-34 show alternative embodiments of the system of Figures 27 and 28.

DETAILED DESCRIPTION

[0027] As described above, inevitable vibrations are created when a shell component is machined which can be detrimental to the accuracy of the machining process or damage the component. Many prior art systems for damping the vibrations produced during shell machining give rise to unwanted effects such as deformation of the component. The present invention provides a system for damping vibrations in a component during machining of that component, that overcomes the problems associated with the prior art. The skilled person will appreciate that the present invention may be used to provide damping in a variety of technical fields and is not restricted to the machining of shell components. Nevertheless, the foregoing embodiments are described in relation to shell component machining.

[0028] Figure 1 shows a sectional side view of a damping system 10 according to the invention. The damping system comprises a support 12 in the form of a support block or other suitable fixture. The support 12 has an operating surface 14 for supporting a component 16 thereon which comprises a series of grooves 18. As described further below, the grooves in the operating surface 14 can be either boundary grooves 18a or isolating grooves 18b. The boundary grooves 18a run along outer most edges of the operating surface 14 while the isolating grooves 18b traverse the operating surface 14 between the edges.

(0029] A squeeze film of damping fluid 20 is provided on the operating surface 14 to provide a damping force (when in use) between the component 16 and the support 12. Suitable damping fluids include water based liquids, oil based liquids and colloids. Specific damping fluids can be chosen based on the particular type of machining or particular type and/or form of the component that is to be machined. It is especially preferable that the damping fluid is not a hazardous substance, does not produce hazardous vapours and may be disposed of easily.

The damping properties of squeeze films are well known in the art.

[0030] During the machining process, the component 16 is placed on the film of damping fluid such that the component 16 is separated from the operating surface 14 by a gap 22. In a preferable embodiment, the profile of the support 12 and/or the profile of the operating surface 14 are/is shaped so that they/it are/is complimentary to the profile of the component. When placed onto the operating surface 14, the damping fluid 20 exerts an upward force on the component 16 that suspends the component above the support 12. A spacing S between the suspended component 16 and the base of the grooves 18 is preferably around 1 mm or less.

The actual size of the spacing S may depend on the viscosity of the damping fluid 20 used.

Once the component 16 is located on the support 12 the machining process can begin.

Typically the side of the component 16 that is opposite the side that is to be machined will be damped. Referring to Figure 1, it is more preferable to machine an upper side 16a of the component 16 whilst damping a lower side 16b.

[0031] During machining, the component 16 will oscillate back and forth relative to the support 12. Figure 1 shows the component 16 as it is moving towards the support 12 (indicated by arrow A) due to vibration arising from machining. The downward moving component 16 compresses the film of damping fluid 20 that covers the operating surface 14 into the grooves 18 and away from the gap 22. The gap 22 is reduced to size C as indicated in Figure 1. The compressed damping fluid 20 exerts an upward force on the downward moving component 16 to retard its motion.

[0032] As the oscillation due to machining continues, the component 16 stops moving downwards and comes to rest before moving upwards relative to the support 12. Figure 2 shows the system as the component 16 is moving upwards with respect to support 12 (indicated by arrow B). As the component 16 moves upwards, damping fluid 20 is drawn from the grooves 18 (which serve as reservoirs of damping fluid 20) into the expanding gap G' (G'>G). In alternative embodiments, the operating surface 14 may not comprise grooves 18 at all, but reservoirs of another form. Due to viscous and inertia forces, the damping fluid 20 exerts a downward force on the component 16 to retard its upward motion. As the component 16 continues to oscillate upwards and downwards relative to the support 12 due to machining vibration, its motion will be damped by the damping fluid 20. The specific dimensions of the system 10 and the properties of the damping fluid 20 will determine the actual level of damping (i.e. the damping factor) and can be tailored to produce the desired level for a particular application. The present invention is capable of providing damping with a damping factor greater than 1.0. In some situations, the gap 22 may be reduced to zero and all of the damping fluid 20 will be disposed in the grooves 18.

[0033] Figure 3 shows a detailed top down view of one embodiment of the support 12. The support 12 comprises boundary grooves 18a around each outer edge of the operating surface 14. Figures 1 and 2 can be considered to be sectional side views taken along section I-I of Figure 3, taking the grooves 18 of Figures 1 and 2 to be boundary grooves 18a. Similarly, Figures 1 and 2 can be considered to be sectional side views taken along section I-I of any of Figures 4 to 16, taking the grooves 18 of Figures 1 and 2 to be either boundary grooves 18a or isolating grooves 1 8b where appropriate.

(0034] Figure 4 shows a top down view of an alternative embodiment of the support 12 comprising intersecting isolating grooves 18b in the operating surface 14. The isolating grooves 18b segment the operating surface 14 into four distinct areas, namely 14a, 14b, 14c and 14d, and provide intermediate reservoirs along the operating surface 14 for the damping fluid 20 to flow in and out of during vibration. The effect of the isolating grooves 18b, therefore, is to isolate areas of vibration so that each segmented operating surface 14a-d damps a part of the component 16 that is immediately above that segment (e.g. 14a), and does so substantially independently of the behaviour of the component above other segments (e.g. 14b, c and d).

The isolating grooves 18b achieve this effect by preventing the damping fluid from flowing from one area to another. The squeeze film damping system 10 according to the present invention does not require any sealing like prior art systems and can therefore be described as an "open" system. In particular, this is because the surface tension of the damping fluid 20 prevents the fluid from leaving the operating surface 14 and the surface of the component and the grooves 18 restrict flow of the damping fluid 20 across the operating surface 14 Therefore, the component 16 has a close tolerance with the damping medium and can be machined and damped by the present invention without being preloaded or sealed so that the quality or accuracy of the machining is not compromised. In addition, no external power source is required to pump or pressurise the damping fluid.

[0035] At an intersection point of two isolating grooves 18b, the support 12 of Figure 4 further comprises a pressure equalisation hole 24. The pressure equalisation hole 24 provides a fluid passageway from the operating surface 14 to the external world through the support 12 and serves to balance the pressure in the two isolating grooves 18b and the external world. In general, any number of pressure equalisation holes 24 may be employed to establish a fluid passageway between the reservoir(s) (e.g. grooves 18) and the external atmosphere.

[0036] Figure 5 shows a further alternative embodiment of the support 12 which comprises boundary grooves 18a in the operating surface 14, isolating grooves 18b and a plurality of pressure equalisation holes 24 at the intersection points.

[0037] Figures 6 to 8 illustrate several alternative embodiments based upon a circular support 14. In particular, Figures 7 and 8 demonstrate that the isolation grooves 18b may be curved and/or straight, defining segments of any shape.

[0038] Indeed, as is shown in Figures 9 to 11, the boundary grooves may also be straight and/or curved. The actual geometry of the support 12 and the configuration of the boundary grooves 18a and the isolating grooves 18b may be tailored to the geometry and dimensions of a specific component that is to be machined. Furthermore, it may be preferable to design the arrangement of isolating grooves 18a so that anticipated areas of vibration in a component (during machining) can be isolated from one another.

[0039] Figures 12 to 16 show a further alternative embodiment of the present invention where the support 12 is annular. An annular support 12 such as those shown in Figures 12 to 16 may be useful when machining annular components (see also Figures 27 and 28 for further

examples).

[0040] Figures 17 to 26 show sectional side views of various embodiments and arrangements of the squeeze film damping system 10 in use. In particular, Figure 17 shows the component 16 being supported along its single lower side 16b by a single support 12 leaving its upper side 16a to be machined. Of course, it is conceivable that any exposed surface of the component 16 can be machined. As described above, the support 12 has an operating surface 14 and the component 16 and the operating surface 14 are separated by gap 22. The damping fluid 20 is disposed intermediate the component 16 and the support 12 in the gap 22 to provide damping of the component 16 as it moves (vibrates) relative to the support 12 due to the machining.

[0041] Figure 18 shows an alternative embodiment of the squeeze film damping system 10 where the component 16 is supported along part of its lower side 1 6b by a first support 1 2a and along part of its upper side 16a by a second support 12b. Both supports 12a, 12b have respective operating surfaces 14a, 14b that are separated from the respective lower side 16b and upper side 16a by gaps 22a, 22b. Each gap 22a, 22b comprises damping fluid 20a, 20b which serves to damp vibrations in the component 16 as described above. In the specific -embodiment shown in Figure 18, the component 16 is damped along a single axis 100 by both the first support 12a and second support 12b. Although Figure 18 shows the component 16 to be only partially supported along its upper side 16a and lower side 16b, in alternative embodiments the entirety of the upper side 16a and lower side 16b may be supported by supports 12a, 12b. Thus, the component 16 can be axially restrained between two or more supports (e.g. 12a, 12b) that effectively clamp the component 16 negating the requirement of any other clamping means. Returning to the embodiment depicted in Figure 18, the arrangement allows any exposed surface of the component 16 to be machined such as ends 1 6c or 1 6d, or indeed the exposed portions of the upper side 1 6a or the lower side 1 6b.

[0042] In Figure 19, the component 16 is supported along its lower side 16b only by three supports 12a, 12b and 12c. The three supports 12a, 12b, 12c are arranged at intervals along the lower side 16b of the component 16 although the actual arrangement may vary. Figure 19 demonstrates that any number of supports 12 may be used to support a component 16 and that the actual positions of the supports 12 relative to the components 16 can be altered to provide more or less support at specific locations along the lower side 16b of the component 16 as desired. Any remaining exposed surface of the component 16 can be machined once mounted on the supports 12a, 12b, 12c.

[0043] In Figure 20, the component is supported along a lower side 16b by three supports 12a, 12b and 12c and along an upper side 16a by an additional three supports 12d, 12e and 121. As with the embodiment shown in Figure 19, the actual positions of the supports 12a-12f may be positioned to provide additional support as desired along the component 16.

(0044] Indeed, a single support 12 may comprise more than one operating surface 14 and be arranged to provide damping along different axes. Referring to the embodiment in Figure 21, the single support 12 has two orthogonal operating surfaces 14 and 14'. Damping can therefore be provided by the single support 12 against two different orthogonal surfaces 16a, 16b of the component leaving all exposed surfaces to be machined as required. In the embodiment shown in Figure 21, the support 12 has been specially designed to provide damping for a component 16 with a right-angled portion 16a, 16b.

(0045] A variation of the embodiment shown in Figure 21 is depicted in Figure 22 where the component 16 is supported along two right-angled sections 16a, 16b and 16c, 16d by two separate supports 12a, 12b. Each support 12a, 12b has two orthogonal operating surfaces 14a, 14a' and 14b, 14b' respectively that provide support to the two right angled sections iGa, 16b and 16c, 16d. Of course, in alternative embodiments operating surfaces may not be orthogonal to one another but be arranged at any angle relative to one another.

(0046] In Figure 23, an embodiment is shown where the support 12 has three operating surfaces 14, 14', 14" supporting sides 16a, 16b and 16c of the component 16. As illustrated in the examples shown in Figures 24 to 26, any number of supports 12 may be used where each may have multiple operating surfaces 14 that have a film of damping fluid 20 (not shown) to damp a component 16 along multiple surfaces. The present invention is not restricted to any particular configuration or those depicted in the Figures. It will be apparent to the skilled person that any appropriate combination of supports and operating surfaces may be used to provide efficient and effective damping to a component of irregular shape or otherwise.

(0047] To further illustrate the invention in use, Figures 27 to 32 are perspective views of several possible arrangements used to provide damping for a annular component 16.

(0048] Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0049] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0050] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

CLAIMS1. A damping system for damping vibrations in a component during the machining of the component, said system comprising at least one support having at least one operating surface; at least one reservoir in fluid communication with said at least one operating surface; and a squeeze film of a damping fluid disposed on said at least one operating surface wherein the damping fluid is adapted to flow into and out of said at least one reservoir in response to vibrations in a component supported on said squeeze film and damp vibrations in the component.
2. The damping system of claim 1, further comprising one or more pressure equalisation holes providing fluid communication between said at least one reservoir and the external environment.
3. The damping system of claim I or 2, wherein said at least one reservoir is a plurality of grooves in said at least one operating surface.
4. The damping system of claim 3 when dependent on claim 2, wherein said one or more holes is or are located in said grooves.
5. The damping system of claim 4, wherein said grooves intersect one another at intersection points and said one or more holes is or are located at said intersection points.
6. The damping system of claim 3, 4 or 5, wherein said grooves comprise one or more boundary grooves around edges of said at least one operating surface and one or more isolating grooves that traverse said at least one operating surface between said edges.
7. The damping system of any preceding claim, wherein said at least one operating surface is planar.
8. The damping system of any preceding claim, wherein said at least one operating surface is annular.
9. The damping system of any preceding claim, wherein said at least one operating surface is adapted to receive said film for supporting a component along one surface of said component.
10. The damping system of any of claims ito 8, comprising at least two operating surfaces, wherein said at least two operating surfaces are adapted to receive said film for supporting a component along more than one surface of said component.
ii. The damping system of any preceding claim, comprising at least two supports.
12. The damping system of any preceding claim, wherein said damping fluid is a water based liquid.
13. The damping system of any of claims I to 11, wherein said damping fluid is an oil based liquid.
14. The damping system of any of claims I to 11, wherein said damping fluid is a colloid.
15. The damping system of any preceding claim, wherein the damping fluid is re-usable.
16. The damping system of any preceding claim, wherein a damping factor of 1.0 or above is achieved.
17. A damping system substantially as hereinbefore described with reference to the accompanying drawings.