EP1285182A1

EP1285182A1 - Variable or non-variable amplitude vibrating wave damping device

Info

Publication number: EP1285182A1
Application number: EP01940625A
Authority: EP
Inventors: Alain Le Mehaute; François ANGOULVANT; François TSOBNANG; Carole Challioui
Original assignee: Ismans - Institut Superieur des Materiaux du Mans
Current assignee: Ismans - Institut Superieur des Materiaux du Mans
Priority date: 2000-05-31
Filing date: 2001-05-29
Publication date: 2003-02-26
Also published as: AU2001274144A1; WO2001092754A1; FR2809785A1; FR2809785B1

Abstract

The invention concerns a variable or non-variable amplitude vibrating wave damping device. Said device is characterised in that it is in the form of a rigid beam (1) or beam section (1) in the axis of the neutral fibre and having, between an incident surface (2) and a radiating surface (3), rigidly linking walls (4) deformable by geometric construction along two opposite directions under the effect of the vibrating wave (o) applied to the incident surface (2), said linking walls (4) stressing as they are deformed at least a damping element (5), preferably housed inside the beam (1) or the beam section (1).

Description

Vibration wave damping device of variable or non-variable amplitude

The present invention relates to a vibratory wave damping device of variable amplitude or not and an element, in particular a construction element, incorporating such a device.

When a wall is either subjected to an incident pressure wave or is vibrated by mechanical means, the incident pressure wave and / or vibrations are transmitted through the structure of the material from the incident surface to the radiant surface. Similarly, when a structure generates vibrations, these vibrations are emitted by connections to surrounding structures. These transmitted waves can be bothersome and cause premature aging.

Many devices have therefore been developed to date to reduce or even eliminate the transmitted waves so as to prevent a vibrating device from generating a vibro-acoustic wave in the medium which surrounds it, in particular by connecting the vibrating device to the surrounding structures. To reduce the vibrational energy transmitted by a wall or by a vibrating structure to its support, several solutions have been developed to date.

Some solutions consist in using shock absorbers formed of elastic blocks, such as rubber blocks, or in elastic synthetic material called "silent-blocks", capable of separating or isolating the vibrating element from its support or, conversely, the element carried from its vibrating support. The major drawback of these devices is linked to their lack of resistance over time and to their low mechanical rigidity which prevent them from being used as a rigid support structure. However, in certain cases, the connections between the vibrating structure and its environment, in particular a fixed support, must have a high rigidity. Furthermore, the filtering capacities of such devices under heavy load are low. Indeed, although attempts to stiffen the rubber blocks have been imagined as illustrated by patent FR-A-0,904,850, these solutions are not satisfactory because the side walls of the block are made of rubber deforming randomly and leading to the formation of non-rigid side walls. It is the same in the solution described in US-A-3,575,403 in which the structure consists of elastomeric locations sandwiched between rigid surfaces. The presence of elastomers results in the formation of deformable and non-rigid side walls. Thus, during a load exerted on the upper surface of the structure, the latter deforms in a non-linear manner, which results in a lack of reliability in load due to the lack of vertical rigidity.

Another solution consists in attenuating the emission of vibrations by a device incorporated in parallel with the vibrating structure. This technique allows extremely high intrinsic damping of the structure under low load. An exemplary embodiment of such a structure is described in particular in the international application. O / 97.11451. However, such structures cannot be used as an element of interposition between vibrating structure and support. Furthermore, such structures are only effective in the case of vibrations normal to the emissive walls. Finally, there is another type of damper in which the viscoelastic material is replaced by a suitable geometry in which a liquid flows. This is the case of the damping device described in patent US-A-5,054,753 in which the liquid can compress a spring. Again, the rigidity following a component parallel to the vibratory wave applied to the incident surface of the structure is low and the deformations of this structure uncontrollable.

An object of the present invention is to provide a vibration wave damping device, the design of which makes it possible to be interposed between the vibrating structure and the support, ensuring precise maintenance in position of the vibrating structure due to the rigidity of the damping device while ensuring high vibration filtration power.

Another object of the present invention is to provide a vibration wave damping device having the advantages of a traditional rubber damping block in terms of absorption of the filtrations while preserving an extremely high rigidity.

To this end, the subject of the invention is a vibratory wave damping device of variable or not amplitude, intended in particular to be interposed between a vibrating structure and a fixed support structure, characterized in that it is in the form of '' a beam or a section of rigid beam in the axis of the neutral fiber and having, between an incident surface and a radiating surface, rigid connecting walls shaped to present by geometrical construction points or zones of localized geometric weakness ensuring maintenance of the rigidity of said walls in one axis of the neutral fiber while allowing deformation of said walls in two opposite directions under the effect of the vibratory wave applied to the incident surface, said connecting walls urging during their deformation at least a damping element, preferably housed inside the beam or the edge of the beam.

Thanks to the design of this damping device, the latter can be interposed between a vibrating structure and a support, ensuring precise maintenance in position of the vibrating structure due to its rigidity, while guaranteeing a high filtering power of vibrations between structure. vibrating and support.

Such a damping device has a structure capable of associating a rigid behavior in dynamics and in static with a viscoelastic behavior in precise fields of low frequencies.

Another subject of the invention is an element, in particular a construction element, of the type consisting of a network of elementary meshes, characterized in that each elementary mesh is constituted by a damping device of the preceding type.

Examples of embodiments include cushioning floors or the like.

The invention will be clearly understood on reading the following description of exemplary embodiments, with reference to the appended drawings in which:

Figure 1 shows a schematic sectional view of a device according to the invention;

Figures 2 to 4 show schematic sectional views corresponding to alternative embodiments of the damping device shown in Figure 1.

As mentioned above, the vibration damping device of variable or non-variable amplitude, object of the invention, is more particularly intended to be disposed between a vibrating structure and a support of said structure. It can therefore be used as a replacement for elastic shock-absorbing blocks used in particular in the naval, aeronautical, space, automobile and railway industries. This device is in the form of a beam 1 or a slice of beam 1 rigid in the axis of the neutral fiber. By way of example, this structure could be made of metallic, polymer and composite materials.

This beam 1 or slice of the beam can be hollow or solid and produced symmetrically or not. This beam or slice of beam also has, between an incident surface 2 and a radiating surface 3, connecting walls 4. These connecting walls 4, rigid in the axis of the neutral fiber to give the device its rigidity, are shaped to be, under the effect of a vibrating o wave, deformable in two opposite directions shown in Dl in the figures. For this purpose, the connecting walls 4 have points or zones 7 of geometrically localized rigid weaknesses ensuring the rigidity of said walls in the neutral fiber axis while allowing deformation along Dl. Thus, in certain examples shown, these connecting walls 4 affect the shape of dihedrons, the edge of the dihedron constituting by construction the zone 7 of weakness, this edge kept rigid along the axis of the neutral fiber allowing deformation of the following dihedron a direction D1 perpendicular to the direction of the vibratory wave o applied to the incident surface. In other words, the lateral connecting walls 4 deform in a direction substantially parallel to the incident surface 2. The deformation of the lateral walls 4 due to the construction and the geometric shape of these walls 4 and the presence of the zones 7 of weakness makes it possible to have non-randomly deformable walls while maintaining rigidity along the axis of the neutral fiber.

Applied to the incident surface 2, this vibratory wave o can emanate in particular from any vibrating structure, such as a machine tool or the like. The deformations of the connecting walls 4, under the effect of this vibrational wave o will be micro-displacements between the fraction of micron and the meter due to the rigidity of the structure which may be included in the range [1,000 - 200,000] N / mm.

To obtain maximum efficiency in terms of filtering, at least one component of the deformation 1 of the walls 4 connecting the beam 1 is perpendicular to the direction of the vibratory wave o applied to the incident surface 2.

Characteristically with the invention, these connecting walls 4 preferably stress in shearing, during their deformation, at least one damping element 5. This damping element 5 is preferably housed inside the beam 1 or the edge of the beam 1.

In the examples shown in Figures 1 to 3 corresponding to a preferred solution of the invention, at least one damping element 5 is disposed between the connecting walls 4 and connects the latter between them.

In a still particular embodiment, at least one damping element 5 constitutes the connection, in particular the joint plane, between two partitions, preferably overlapping, coming from the connecting walls 4 of the beam 1.

In another less efficient and shown in Figure 4, at least one damping element 5 is disposed between incident surface 2 and radiating surface

3 of the beam 1. In this case, again, the damping element 5 can constitute the connection, in particular the joint plane, between two partitions, preferably overlapping, originating from the incident 2 and radiating 3 surfaces.

Depending on its positioning and the geometric design of the connecting walls 4, the damping element 5 may be subjected to shear forces or to tensile or compressive forces. Submission to shear forces is a preferred solution as illustrated by the figures because it allows more filtering. Similarly, the entire beam 1 can have a large number of shapes. Thus, connecting wall 4, incident 2 and radiating 3 surfaces and damping element 5 can define in section two open polygons joined by one of their sides to form in the assembled state a closed structure as shown in Figures 1, 2 and 4 In the exemplary embodiment of these figures, connecting wall 4, incident 2 and radiating 3 surfaces and damping element 5 define two open polygons joined by their small base (FIG. 2) or by their large base (FIGS. 1 and 4). for _^ form when assembled a closed structure.

Obviously, this elementary structure can also be added to other structures to form, for example, a building element such as a floor capable of withstanding significant static forces and of filtering the vibrations generated by the shocks undergone. Any other application could obviously be envisaged on the basis of such an assembly. In this case, each elementary mesh is constituted by a damping device of the aforementioned type.

The damper element can also affect a large number of shapes. In the exemplary embodiments shown, this damping element consists of a viscoelastic material, such as a polymer based on acrylic or natural or synthetic elastomers, based on silicones, phosphazenes.

In the case of the examples shown where this viscoelastic element is used as a joint plane between two overlapping partitions 6 coming from the connecting walls 4, the viscoelastic material is subjected essentially to shearing forces by the deformation of the beam or the edge of the beam. In other embodiments, not shown, the damping element could also consist of an oleo-pneumatic member or a pneumatic member without departing from the scope of the invention.

In all the examples shown in the figures, the beam 1 or rigid beam section 1 has been shown hollow. However, it could be filled with a viscoelastic material or any other damping device. Similarly, the section of this beam can be arbitrary from the moment when it has rigid deformable connecting walls under the effect of a vibrating wave applied to the incident surface of said beam as illustrated in all the figures.

In the examples shown, the beam 1 is a symmetrical structure in which the connecting walls are geometrically opposite walls. However, symmetry is not a mandatory feature of the invention.

The manufacture of a damping device is extremely easy. Thus, in the embodiments shown in FIGS. 1 and 2, it suffices to have two open polygons respectively formed, for example, one of the incident surface, the other of the radiating surface. a part of the connecting walls and at least one partition coming from the connecting wall. It is then necessary to join the two open polygons, in this case the trapezoids, by one on their side on the one hand by means of a rigid connection, on the other hand by means of the viscoelastic element constituting the damping element, for example simply by soaking the structure in a bath of viscoelastic material. The damping device is then completed.

This damping device can be used in particular as an interposition element between a vibrating structure (not shown) and a support, said support having been shown in the figures by hatching. The applications of this device are numerous, in particular in the automotive field in place of or as a complement to rubber blocks and shock absorbers, in the naval field as a support or structure link in vibration (engine bridges, propeller shaft) in the field rail as support for railway sleepers, in rail structures and finally in the field of aviation for any support or rigid link.

Claims

1. Vibration wave damping device of variable or not amplitude, intended in particular to be interposed between a vibrating structure and a fixed support structure, characterized in that it is in the form of a beam (1) or of a slice of beam (1) rigid in the axis of the neutral fiber and having, between an incident surface (2) and a radiating surface (3), rigid connecting walls (4) shaped to present points by geometric construction (7) or zones of localized geometric weakness ensuring the rigidity of said walls in the axis of the neutral fiber while allowing deformation of said deformable walls in two opposite directions (Dl) under the effect of the wave (o ) vibration applied to the incident surface (2), said connecting walls (4) urging during their deformation at least one damping element (5), preferably housed inside the beam (1) or the edge from p addition (1).

2. Device according to claim 1, characterized in that at least one damping element (5) is disposed between said connecting walls (4) and / or between incident surface (2) and radiating surface (3) and connects the latter between them.

3. Device according to one of claims 1 and 2, characterized in that at least one component of the deformation (Dl) of the walls (4) connecting the beam (1) is perpendicular to the direction of the wave (o) vibration applied to the incident surface (2).

4. Device according to one of claims 1 to 3, characterized in that at least one damping element (5) constitutes the connection, in particular the joint plane, between two partitions (6), preferably overlapping, from connecting walls (4) or respectively incident (2) and radiant (3) surfaces.

5. Device according to one of claims 1 to 4, characterized in that walls (4) of connection, incident surface (2) and radiating (3) and element (5) damper define in section two open polygons joined by one of their sides to form in the assembled state a closed structure.

6. Device according to one of claims 1 to 5, characterized in that walls (4) of connection, incident (2) and radiating (3) and damping element (5) define in section two open trapezoids joined by their small base or their large base to form in the assembled state a closed structure.

7. Device according to one of claims 1 to 6, characterized in that the damping element (5) is subjected essentially to shear forces by the deformation of the beam or of the beam edge.

8. Device according to one of claims 1 to 7, characterized in that the damping element is a viscoelastic material.

9. Device according to one of claims 1 to 6, characterized in that the damping element is an oleopneumatic or pneumatic member.

10. Device according to one of claims 1 to 9, characterized in that the rigidity of the walls (4) of connection is included in the range [1,000 - 200,000] N / mm.

11. Element, in particular construction element, of the type consisting of a network of elementary meshes, characterized in that each elementary mesh is constituted by a damping device according to one of claims 1 to 10.