Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F7/00—Vibration-dampers; Shock-absorbers
  • F16F7/10—Vibration-dampers; Shock-absorbers using inertia effect
  • F16F7/104—Vibration-dampers; Shock-absorbers using inertia effect the inertia member being resiliently mounted
  • F16F7/108—Vibration-dampers; Shock-absorbers using inertia effect the inertia member being resiliently mounted on plastics springs
• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
  • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
  • G10K11/02—Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators
  • G10K11/04—Acoustic filters ; Acoustic resonators
• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
  • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
  • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
  • G10K11/162—Selection of materials

Definitions

• TITLE METAMATERIAU FOR VIBRATION FILTERING AND INSULATING PART MADE WITH LEDIT METAMATERIAU
• the invention relates to a metamaterial intended for filtering vibrations as well as an insulating part made with said metamaterial.
• the invention is concerned with a metamaterial making it possible to ensure isolation with regard to vibrations at the interface of the internal links of a complex structure and, in particular, with respect to phenomena vibrations generated by the rotating members of motor vehicles and / or by external stresses applied to said vehicles.
• TMD Tuned Mass Damper
• auxetic materials have a negative Poisson's ratio and generally have a structure made up of geometric shapes which, under the action of a tensile stress in the longitudinal direction, will extend in the transverse direction.
• Such structures include a block of polyurethane foam with rotating squares, each polygon of which contains a metal cylinder.
• This double porosity material can thus, depending on its compression, significantly improve vibration insulation and sound absorption.
• patent FR3016945B1 describes a cellular material allowing shock absorption.
• This material includes a base plate supporting an auxetic structure.
• the cross section of this material has a plurality of through holes which are filled with a damping material.
• Metamaterials are suitable synthetic materials and intended for treating wave phenomena such as vibrations.
• the structure of metamaterials is generally composite and consists of a base integrating resonators.
• the profile and the geometry of the resonators vary according to the type of waves to be processed, but they are generally placed periodically on the base and thus make it possible to guide the waves through the metamaterial.
• the present invention provides a metamaterial whose specific structural geometry is developed with a view to solving the technical problems posed by traditional insulation and / or filtering solutions.
• an insulating metamaterial for filtering vibratory waves the structure of which comprises at least one auxetic modular element, characterized in that said auxetic modular element comprises at least one cell carrying elastically deformable peripheral bridges and including a rigid resonator insert.
• the auxetic modular element comprises four cells interconnected by bridges so as to form a closed loop.
• the walls of the cell and of the intercellular bridges are made in one piece and in the same elastomeric material and in that the rigid resonator insert is made of metal.
• the thickness of the bridges is at least equal to that of the wall of the cell.
• the bridges extend perpendicularly to each other at the periphery of the cell.
• the cell has a substantially circular section, the interior volume of which is entirely occupied by the rigid resonator insert.
• the cell is cylindrical and carries four bridges which extend radially and in a diametrically opposed manner in pairs.
• the cell is spherical and carries six bridges.
• Another object of the invention is an insulating piece of metamaterial for filtering vibrations in motor vehicles comprising a series periodic auxetic modular elements as defined above, connected to each other by bridges.
• this insulating part is in the form of a plate or of a block.
• the metamaterial of the invention through its static and dynamic characteristics, makes it possible to obtain a compact vibration isolation system affecting a wide range of frequencies.
• the system has a stiffness plateau (zone of zero stiffness) after compression.
• a stress state close to this plateau allows more extensive dynamic filtering of the vibrations. In practice, this state would be reached by taking up the mass of the system to be isolated (static stress).
• the material has frequency zones in which the waves cannot propagate.
• the metamaterial of the invention while having a low cost, offers better performance compared to traditional insulation materials and without increasing the bulk because it can be implanted in the existing intermediate space or equivalent.
• the insulation material of the invention presents an excellent compromise between cost, performance, reliability and quality. [0033] Other characteristics and advantages of the invention will become apparent on reading the description which follows, with reference to the appended and detailed figures below.
• FIG. IA is a front view of a first embodiment of the auxetic metamaterial of the invention in the free state (unconstrained).
• FIG. IB is a front view of the embodiment of Figure IA in the pre-stressed state under compression.
• FIG. IC is a front view of the embodiment of Figures IA and IB deformed under stress.
• FIG. 2A is a front view of an auxetic metamaterial according to the invention produced by the assembly of several modular elements according to the embodiment of Figure IA.
• FIG. 2B is a front view of the auxetic metamaterial of Figure 2A in the deformed state under compression.
• FIG. 3 is a graph representing the stiffness curve of the metamaterial of FIG. 2A.
• FIG. 4A is a graph representing the frequency zones of the forbidden bands of vibratory waves as a function of the dimensions of local resonators.
• FIG. 4B is a graph representing the effects of deformation on the frequencies of the forbidden bands of vibratory waves.
• FIG. 5 is a perspective view of a second embodiment of the auxetic metamaterial of the invention in the free state (unconstrained).
• the invention relates to an improved auxetic metamaterial, intended for filtering vibratory waves and whose structure comprises at least one cellular modular element.
• the invention relates to filtering and / or absorption of vibrations at the connection interface between various components mounted in a mechanical assembly.
• the auxetic metamaterial of the invention finds a specific application in the filtering of vibrations generated by rotating machines and / or external stresses.
• a field of application specifically targeted by the insulation metamaterial of the invention is in the automotive sector where the metamaterial is used for the manufacture of insulating parts.
• a material with auxetic properties is characterized by a negative Poisson's ratio.
• the Poisson's ratio corresponds, in absolute value, to the ratio between the transverse stress of a material and its longitudinal stress. This coefficient therefore reflects the transverse deformation capacity of a material.
• the modular auxetic element of the metamaterial of the invention comprises at least one cell carrying elastically deformable peripheral bridges and enclosing a rigid resonator insert.
• the modular auxetic element 1 constituting the vibration isolation metamaterial of the invention comprises here only four cells 10 (respectively 10a, 10b, 10c and 10d ) interconnected by elastically deformable bridges 11 forming a closed loop. Each cell contains a rigid resonator insert 12.
• the insulation metamaterial of the invention may comprise a periodic series of auxetic modular elements 1 connected to each other by intercellular bridges 11 in forming a plate P of uniform or variable thickness.
• the structure of the metamaterial of the invention then consists of a regular arrangement of composite cells in space.
• the preferred embodiment of the metamaterial of the invention consists in assembling several auxetic elements 1 in closed loops 1a each formed of four cells 10.
• the walls of the cells 10 and of the bridges 11 are made in one piece and in the same very elastic material, for example, an elastomer with a low dissipation coefficient.
• the thickness of the bridges 11 is at least equal to the thickness of the wall of the cells 10.
• the elastomeric material constituting the wall of the cells 10 and that of the bridges 11 is preferably chosen from the group comprising; silicone, TPU, .... while the resonator insert 12 is made with a high density material, for example, a metal chosen from the group comprising steel, lead, ...
• each cell 10 is extended radially by four bridges 11 which project from the periphery of the cell and diametrically opposed.
• the bridges 11 are arranged on perpendicular diameters of the cell 10.
• the cells 10 have a substantially circular or polygonal section, the interior volume of which is entirely occupied by the rigid resonator 12 which is encapsulated and integral with the wall of the cell. It follows that, under stress, the wall of cells 10 undergoes little or no deformation, unlike bridges 11.
• the metamaterial of the invention is produced by means of a modular element 1 in a loop ( Figure IA) with four cells 10, or in the form of a plate P formed of the union of several modular elements 1 (FIG. 2A) extending in the same plane.
• the metamaterial of the invention can be used to manufacture insulating parts having all profiles and all geometries on condition that the modular elements 1 are used periodically in a closed loop.
• FIG. 2B The state of deformation of the plate P in insulating metamaterial as it results from compression is illustrated in FIG. 2B (with 5% deformation) while FIG. 3 represents the stiffness curve of the plate P of material (obtained by numerical simulation).
• the areas of greatest stress are located here at the level of the lateral intercellular bridges.
• the curve in Figure 3 shows two main trends: on the one hand, an initial quasi-linear slope and, on the other hand, a plateau where the stiffness is close to zero. Such a stiffness value makes it possible to treat vibrations optimally and to isolate the components to be protected.
• FIG. 4A represents approximately the dimensions of the forbidden bands as a function of the radius of the resonator inserts 12 and of the frequencies f, for a compression ratio of 20%.
• FIG. 4B represents the influence of the compression deformation on these forbidden bands as a function of the frequencies f, for resonator inserts 12 of radius 2mm.
• the auxetic metamaterial according to the invention is used to produce insulating parts by extrusion in two dimensions, that is to say in the form of a block or of a plate having a constant section in the third direction (perpendicular to the plane of figures).
• This variant which is illustrated in particular by FIGS. 2A and 2B, makes it possible to have resonators of significant mass and a different stiffness in this third direction, which may prove useful depending on the applications.
• the envisaged manufacturing process uses a 3D printed mold to perform the molding of the plate P with an elastomeric material of the silicone type.
• the cells 10 and the resonator inserts 12 are then no longer cylinders, but spheres, which reduces their mass and therefore their potential effect but which allows to have forbidden bands for vibrations in all directions.
• the spherical cells then carry six bridges 11 for connection with the adjacent cells 10 and the manufacturing process will use either a lost mold in negative, or a suitable 3D printing.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• Multimedia (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Vibration Prevention Devices (AREA)
• Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
• Filtering Materials (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=67956944

Family Applications (1)

Country Status (3)

Families Citing this family (8)

Family Cites Families (4)

• 2019
  • 2019-04-10 FR FR1903816A patent/FR3095023B1/fr active Active
• 2020
  • 2020-03-09 WO PCT/FR2020/050479 patent/WO2020208323A1/fr unknown
  • 2020-03-09 EP EP20725860.9A patent/EP3953603A1/de active Pending

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