IT201900002195A1 - ISOLATOR DEVICE, SUCH AS A SEISMIC ISOLATOR OR A SUPPORT ELEMENT FOR CONSTRUCTIONS, INTEGRATED WITH SENSORS - Google Patents

Description

Description of Italian Patent of Industrial Invention entitled:

"ISOLATOR DEVICE, SUCH AS A SEISMIC ISOLATOR OR A SUPPORT ELEMENT FOR CONSTRUCTIONS, INTEGRATED WITH SENSORS"

TECHNICAL FIELD OF THE INVENTION

The present invention refers to an isolating device, such as a seismic isolator or to a support element for constructions, such as for example buildings, bridges, large structures, infrastructures in general equipped with an overlying structure. By constructions we can also mean non-structural works such as pedestals for artistic works, such as statues or similar, for furniture, for industrial machinery, etc., also equipped with an overlying structure.

This isolating device is applied to such constructions to isolate or separate or distance the overlying structure of said construction and a part of said construction integral with the foundations or with the ground in order to dissipate and / or absorb the forces or energy generated by an earthquake or a dynamic stress to which said construction is subjected.

In particular, the present invention refers to an isolating device, such as a seismic isolator or to a support element, in which said isolating device comprises at least one constituent material whose mechanical behavior, including its deformation, varies according to the type of stress or, in any case, as a function of the forces or energy generated by an earthquake or by a dynamic stress to which said construction and therefore the isolator device itself is subjected.

STATE OF THE PRIOR ART

It is known that "seismic isolators" are those devices that serve to isolate the supporting structure of a building or building from the ground in order to reduce or eliminate the destructive effects of an earthquake.

For the same purpose, support devices have also been used in recent years, usually made of elastomer and steel or steel-Teflon, or hydraulic devices, in order to dissipate the energy released by the seismic event and absorb its forces.

In particular, the seismic isolators are positioned between the foundations of a building and the respective structure (developed in height) and thus allow to avoid the creation of resonance phenomena, as these phenomena are the main responsible for the damage caused by a earthquake.

To obtain this result, the seismic isolator or support device must be designed ad hoc for the specific structure under which it must be positioned and allows the latter to act, during the earthquake, almost like a rigid body that tends to remain firm with respect to the vibrations of the ground. At the same time, in the case of new buildings, even the study of the buildings or infrastructures themselves must be modified due not only to the conformation of the land, but also to the presence of such insulators within their construction.

Seismic isolators of the known type, in addition to the reduction of the horizontal forces (and therefore of the stresses internal to the structure), if they have high relative damping values, may also be able to produce a further reduction of the forces in action.

The currently used insulators generally have a structure of rubber or elastomer layers (with low or high damping) alternating with metallic layers, usually of steel.

The purpose of the present invention, therefore, is to provide an isolating device, such as a seismic isolator or a support element, which is improved with respect to those described above and more efficient from a safety point of view of the work itself. The isolator device according to the present invention allows to overcome the drawbacks of the known art.

AIMS OF THE INVENTION

An object of the present invention is to improve the state of the prior art.

A further object of the present invention is to provide an isolating device, such as a seismic isolator or a support element, integrated with one or more chromatic deformation polymeric sensors, for any type of construction, such as a building, a bridge, a infrastructure, etc. By constructions we can also mean non-structural works such as pedestals for artistic works, such as statues or similar, for furniture, for industrial machinery, etc.

A further object of the present invention is to provide an isolating device, such as a seismic isolator or a support element, integrated with one or more polymeric chromatic deformation sensors, which allows:

- to efficiently dissipate the forces and energy developed by an earthquake and / or by the wind and / or by particular atmospheric conditions that generate oscillations or dynamic stresses and / or that can be added to the other dynamic actions to which the building above can be submitted;

- to provide qualitative and / or quantitative information on the extent and direction of the deformation suffered by the device following a seismic event thanks to the variation in the wavelength of the light reflected by the (deformed) sensors.

A further object of the present invention is to provide an isolating device, such as a seismic isolator or a support element, integrated with a chromatic deformation polymeric sensor, which is able - in addition to what is indicated above - to modify its own mechanical behavior in depending on the type and / or intensity of the forces or stress energy to which it is subjected.

According to an aspect of the present invention, an isolating device is provided, such as a seismic isolator or a support element, according to claim 1.

The dependent claims refer to preferred and advantageous forms of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS.

The characteristics of the invention will be better understood by every technician in the art from the following description and the attached drawing tables, given as a non-limiting example, in which:

Figure 1 illustrates a perspective view of an isolator device such as a seismic isolator according to the present invention, partially sectioned so as to view its internal part,

Figure 2 illustrates a perspective view of the seismic isolator referred to in Figure 1, in a version in which it is inserted and fixed to a structure of a building,

Figure 3 illustrates a view corresponding to Figure 2,

Figure 4 illustrates a sectional view taken along the plane of trace IV-IV of Figure 5 of a seismic isolator according to the present invention,

Figure 5 illustrates a top view of the seismic isolator referred to in Figure 4,

Figure 6 illustrates a perspective view of an isolator device such as a support element according to the present invention, in which the external component is partially sectioned so as to view its internal part,

figure 7 illustrates a side view of the support element in figure 6, without its external component,

figure 8 illustrates a sectional view of the support element taken along the plane of trace VIII-VIII of figure 7,

Figure 9 illustrates a version of a component of the isolator device such as the seismic isolator or the support element according to the present invention,

Figure 10 illustrates an external view of an isolating device, such as a seismic isolator (as in Figure 1 but not sectioned), on the surface of which chromatic deformation sensors according to the present invention are applied in a vertical position (with respect to the base of the device) ,

Figure 11 illustrates an external view of an isolating device, such as a seismic isolator (as in Figure 1 but not sectioned), on the surface of which chromatic deformation sensors according to the present invention are applied in a horizontal position (with respect to the base of the device) ,

Figure 12 illustrates an external view of an isolating device, such as a seismic isolator (as in Figure 1 but not sectioned), on the surface of which a chromatic deformation sensor according to the present invention is applied in a vertical position (with respect to the base of the device) (fig.12A) and deformed by an external shear force F (fig.12B): in the case of the figure, the direction of application of the external force (and therefore the direction of the shear displacement of the isolator device) is perpendicular to the surface of the chromatic sensor,

Figure 13 illustrates a version of the Bragg and Snell law formula,

figure 14 shows a simplified and schematic view of figure 12: the isolator device is idealized as a two-dimensional parallelepiped, on the right vertical side of which a one-dimensional strip of length M and height L representing the chromatic deformation sensor is applied (fig.14A) and following deformation (fig.14B),

Figure 15 illustrates a further version of the present invention.

FORMS OF IMPLEMENTATION OF THE INVENTION

The present invention refers to an isolating device, such as a seismic isolator or to a support element, globally indicated with the reference number 1, for constructions, such as for example buildings, bridges, large structures, infrastructures in general, etc. By constructions we can also mean non-structural works such as pedestals for artistic works, such as statues or similar, for furniture, for industrial machinery, etc.

Furthermore, the isolator device 1 can also be used with prefabricated structures, such as for example industrial sheds. In this case, they can be positioned between the plinth and the structure itself, as it avoids placing a concrete element on another concrete element.

The isolator device 1 according to the present invention, such as a seismic isolator or a support element, is integrated with one or more sensors 50. The at least one sensor 50 is capable of providing qualitative and / or quantitative information regarding the characteristics of the deformations suffered by the isolator device 1.

Such at least one sensor 50 is for example a deformation sensor, such as a polymeric chromatic deformation sensor.

The latter acts thanks to the variation in the wavelength of the light reflected by the sensor 50 (when deformed) and provides fundamental information regarding the diagnostics and / or safety of works or constructions. The isolator device 1 is a device capable of isolating or separating or spacing the overlying structure of a building and the part of the same integral with the foundations or with the ground in order to dissipate and / or absorb the forces or energy generated by certain dynamic stresses, such as those caused by an earthquake and / or by the wind and / or by particular atmospheric conditions that generate oscillations and / or which can be added to the other dynamic actions to which the building above can be subjected. In this way, the isolator device 1 according to the present invention is capable of reducing or eliminating the destructive effects of an earthquake or of such dynamic events or stresses. The isolator device 1 is positioned under a structure of a building or work.

In particular, the isolator device 1 can be a seismic isolator 1A, which is positioned, in use, between the foundations F of a building or work and the structure S placed above them (i.e. the superstructure, or structure that develops in height outside the ground). Thanks to this positioning of the seismic isolator 1A, it prevents the creation of resonance phenomena (in the ground or in the structure) of the forces and / or vibrations generated by dynamic stresses (for example caused by the earthquake and / or wind and / or from particular atmospheric conditions that generate oscillations and / or that can be added to the other dynamic actions to which the building above can be subjected, as these phenomena are the main culprits of the damage caused to the building itself).

In a further version, the isolator device 1 can be a support element 1B, which is instead usually positioned under a structure of a building or work, even without being interposed between foundations F and the structure itself, for example between the pylons and spans or trusses of a bridge, viaduct, flyover or similar construction.

The support element 1B can be substantially similar to the support elements of type A, B, C, D, E or F or any additional classes or subclasses.

Usually the isolator device 1 according to the present invention, in its version as a seismic isolator 1A, is positioned in particularly seismic areas while, in its version as a support element 1B - possibly lower than a seismic isolator - it is positioned in order to dampen oscillations or stresses of the structure. However, these functions can also be reversed.

In both cases, as a result of external stresses, the isolator device 1 undergoes deformations (shear, torsion, traction, compression, bending, etc.) usually proportional to the intensity of the stresses themselves.

The present invention improves the prior art by providing qualitative and / or quantitative information regarding the extent and direction of the deformations undergone by the isolator device following a seismic event thanks to the presence of the at least one deformation sensor 50, or for example thanks to to the variation of the wavelength (and therefore of the color) of the light reflected by the sensor 50 (deformed by the earthquake). It therefore represents a new diagnostic technique for assessing the condition of isolating devices and structures.

The isolator device 1 according to the present invention consists of a main body 2 having a substantially geometric solid shape, such as for example a prism or a cylinder, on the external surface of which one or more deformation sensors 50 are applied, such as one or more sensors deformation polymeric chromatics (of any size and shape). The present invention is therefore conceived as composed of two elements intrinsically and inextricably coupled to each other: the isolator device 1 and the at least one deformation sensor 50.

The attached figures 10 and 11 illustrate, by way of example, three deformation sensors 50, such as three polymeric deformation sensors.

The technique of isolator device 1 will be described below.

The main body 2 has two bases 3, 4, substantially parallel to each other and having a polygonal or circular shape.

The bases 3, 4 of the main body 3 are substantially parallel to the ground or perpendicular to a vertical direction along which the height of the superstructure of the building extends.

In particular, in use, the base 3 is the upper base of the main body 2, facing towards the superstructure of the building, while the base 4 is the lower one, facing in use towards the foundations F or the lower part of the structure of the building.

The main body 2 then has a lateral surface 5, given by a tubular surface or by a series of lateral faces thereof.

The distance between the bases 3,4 corresponds substantially to the height H of the side surface 5, considering for height a measurement taken along a direction parallel to the vertical direction of the construction.

The main body 2 comprises a series of first layers 6, parallel to each other and to the bases 3, 4.

In one version of the invention, the first layers 6 are or can be equidistant from each other.

The first layers 6 are interspersed with a plurality of second layers 7.

Therefore, as a whole, the main body 2 of the isolator device is a multilayer. This multilayer, formed by the plurality of first and second layers 6, 7, extends for the height H of the main body 2.

The first layers 6 are in the form of plates or discs having a certain thickness w.

The second layers 7 have a thickness of W.

The choice of thicknesses w and W depends on the design conditions and therefore they can vary from case to case.

In one version of the invention, the thickness w is less than or equal to the thickness W of the second layers 7.

In a further version, the thickness w is greater than the thickness W of the second layers 7.

According to the present invention, the second layers 7 consist of a material whose mechanical behavior, including its deformation, varies according to the type of forces or energy generated by the stress to which the construction is subjected and, therefore, the isolator device 1.

Therefore, the second layers 7 comprise (at least in one version of the invention) a non-Newtonian material, of the pseudoplastic "independent time" type (such as a solution of a polymer, a liquid dispersion of synthetic gum arabic such as tragacanth, gum arabic, sodium alginate, methylcellulose and colloidal dispersions), or of the "independent time" type having an expanding nature (elastomers, viscous silicone liquids such as silicone marketed under the name "Silly Putty" or polymeric matrix foam materials).

The non-Newtonian material of the second layers 7 in a further version of the invention is of the type having a "time dependent" behavior, both of a thixotropic and rheopectic nature.

The non-Newtonian material can entirely constitute the second layers 7 (as a single component) or it can be present as a dopant within a matrix (of a polymeric or non-polymeric nature).

For example, in one version of the invention, this polymeric matrix comprises at least one polymer such as, for example, a natural or synthetic elastomer and / or a mixture of natural and / or synthetic elastomers, or rubber.

As stated above, the isolator device 1 comprises first layers 6.

The first layers 6 have properties of high stiffness and compressive strength. In one version of the invention, the first layers 6 are made of a metal material, for example steel, or of a composite material or a polymeric material.

In the version in which the first 6 layers are made of steel, this - on the basis of the specific legislation in this regard - is S235 steel (corresponding to Fe360). S235 steel has a tensile strength of around 360 Mpa and an elastic modulus of around 200 Gpa. The type of steel usually used, however, can be chosen by the designer and can also be S375 or S355.

In the version in which the first layers 6 are made of a composite material, the latter comprises a composite material formed by a matrix, such as a polymeric matrix, and a plurality of reinforcing elements (e.g. fibers). The presence of reinforcing elements, such as carbon fibers, in the composite material guarantees performance and stiffness superior to other types of fibers or to a material without them.

In a still further version, the composite material that constitutes the first layers 6, may comprise fabrics in natural fibers, such as linen and / or hemp, embedded within a matrix. Such fabrics are lighter for example than glass fibers and therefore, without weighing down the structure, are able to dissipate and / or absorb the vibrations or dynamic stresses to which the isolator device 1 is subjected.

The polymer matrix comprises a material consisting of one or more polymers, such as elastomers, plastics, thermoplastic materials or polymers (such as, for example, Nylon or ABS), or thermosetting polymers, such as, for example, an epoxy resin or a polyester or a phenolic resin , etc..

The polymeric matrix can therefore be constituted by a single polymer or by a mixture of several polymers.

The presence of epoxy resins in the matrix is preferable, in some versions of the invention, as they determine high mechanical and / or cryogenic performance.

By polymeric matrix material we mean a material whose constituent element (which gives the main mechanical, thermal and chemical-physical properties to the material itself) is a polymeric matrix. This polymeric matrix can be doped with any chemical / physical process agent or necessary to give certain properties to the material (e.g. cross-linking agents, antioxidants, antiozonants, accelerators, activators, inert fillers, active fillers, photosensitive materials, thermosensitive, adhesion, flame retardant agents, etc ..).

In one version of the invention, this composite material comprises, as reinforcing elements, carbon fibers, glass fibers or ceramic fibers or aramid fibers, such as for example Kevlar fibers or a mixture of two or more of the following: carbon fibers , glass fibers, ceramic fibers, aramid fibers.

The composite material - comprising reinforcing elements or carbon fibers - comprises, in one version of the invention, a plate of the matrix material (preferably polymeric) obtained by incorporating, within the matrix itself, a fabric or a plurality of fabrics in multilayer of carbon fiber reinforcing elements. The trend of the fibers that make up a layer or at least one layer of the fabric determines the value of the tensile strength of the first layer 6. For example, if the trend of the fibers or layers is perpendicular to each other, there will be a tensile strength greater than when the fibers and / or the different layers of fabric have a parallel trend.

Furthermore, if the fiber is unidirectional, there will be tensile strength only along that direction, as an alternative to resistance in multiple directions when the fibers have orientations along different directions in the fabric or in the first layer 6.

The first layers 6 comprising a composite material, therefore, at least with respect to similar metal layers, have a low specific weight, a low coefficient of thermal expansion, a high mechanical resistance to torsion, a high tensile strength and a high mechanical stiffness.

In a further version, the first layers 6 therefore do not include steel.

In an alternative version of the invention, the first layers 6 are made of a polymeric or matrix material, such as for example a polymeric, as indicated above but without the presence of reinforcing elements.

Consequently, at least in one version of the invention, it is possible to design the product ad hoc, depending on the technical requirements of the application.

The function of the first layers 6, in the multilayer main body 2, is above all structural; these first layers 6, in fact, must resist vertical loads (such as the weight of the building or its structure), distributing the weight and supporting the material that forms the second layers 7.

According to some illustrative and non-limiting examples of the present invention, the isolator device 1 can comprise a multilayer formed by:

i) First layers 6 in steel and second layers 7 comprising a non-Newtonian material, or

ii) First layers 6 in composite material and second layers 7 comprising a non-Newtonian material, or

iii) First layers 6 in polymeric material and second layers 7 comprising a non-Newtonian material, or

iv) First layers 6 of steel and second layers 7 comprising a composite material (such as the one described above for the first layers 6) to which a non-Newtonian material is added, or

v) First layers 6 comprising a composite material and second layers 7 comprising a composite material (such as the one described above for the first layers 6) to which a non-Newtonian material is added.

The isolator device 1 can also comprise an external casing 8, capable of housing the plurality of first and second layers 6, 7.

In one version of the invention, the material that makes up the outer shell 8 is a polymeric matrix comprising at least one polymer such as, for example, a natural or synthetic elastomer and / or a mixture of natural and / or synthetic elastomers.

The external envelope 8 constitutes the external surface of the main body 2 and encloses or houses the multilayer formed by the first layers 6 and the second layers 7.

According to an embodiment example, the external envelope 8 extends for at least 5 mm or for at least 10 mm around the multilayer and / or externally to the first layers 6 and to the second layers 6.

The outer casing 8 protects the isolator device 1 and / or its main body 2 from oxidation that can occur due to the environment in which these devices are positioned.

For this reason, the material that constitutes the external envelope 8 may include an anti-oxidant agent and / or an antiozonating agent and / or an anti-flame agent and / or a dielectric material. The latter, in particular, allows the material of the external casing 8 to be electrically isolated from the surrounding environment. The isolator device 1 according to the present invention is able to perform, at least in one of its versions, its function in a range of temperatures ranging from -40 ° C to 40 ° C. In fact, the material that constitutes the first layers 6 and the second layers 7 alters its characteristics to a limited extent (with variations within the regulatory limits) within this temperature range. In this way, the insulating devices 1 according to the present invention are extremely versatile, as regards the climate in which they can operate and therefore the type of buildings for which they are used. In one version of the invention, the main body comprises a number of first layers 6 ranging from 5 to 50 or preferably from 10 to 40 or even more preferably from 20 to 30.

Similarly, the number of second layers 7 ranges from 5 to 50 or preferably from 10 to 40 or even more preferably from 20 to 30.

However, the number of layers, as well as their thickness, can vary from case to case and is a parameter that is usually established by the designer based on the type of construction with which the seismic isolator 1A or the support element 1B according to the present invention it is used.

The number of layers also varies according to the type of project being carried out and the type of area in which the isolator device 1 is to be used. Therefore, in general, if the number of the first layers 6 is X, the number of the second layers 7 is X 1.

In a further version of the invention, illustrated in Figure 9, the seismic isolator or the support element 1 comprises first layers 16, which can have a sandwich structure, in order to increase their rigidity and strength and at the same time , to implement these properties in the seismic isolator or in the support element 1 according to the present invention.

This version of the first layers 16 provides that each of them comprises a core 18 enclosed by two surfaces, called skins 17, in correspondence with the major surfaces of the first layer 16 or parallel to the bases 3, 4 of the seismic isolator or element of support 1.

These surfaces 17 can be made of a composite material comprising reinforcing elements or fibers, for example of glass or carbon or Kevlar or ceramic or aramid. In this way, this composite material has a high Young's modulus and therefore opposes high resistance to tensile and compressive stresses. This material therefore behaves as if it were inextensible and incompressible.

The first layer 16 according to this version has its surfaces, or skins 17, in which the fibers are formed in stratified.

The material that makes up the internal core 18 of the sandwich is also a material capable of being considered incompressible. In this way, the first layer 16 has a structure with a rigidity far superior to that of a laminate having a thickness equal to the sum of the two hides 17 of the sandwich.

In addition, the material that makes up the core 18 is light.

The core can be made with one of the following materials: a foam material, a foam material such as a thermosetting cross-linked polymer produced in the presence of a blowing agent, the polyurethane foam, or a honeycomb material, such as for example a metal or plastic material having a honeycomb structure (cells), such as alveolar aluminum, alveolar polycarbonate, alveolar polypropylene, etc.

The foam material has a compressive strength which is determined by the density: a high density corresponds to a greater compressive strength.

The core 18 has a thickness Z, given by the distance between the two surfaces or skins 17. The greater the thickness Z, the greater the moment of inertia and therefore the stiffer the structure of the first layer 16 becomes and, consequently, of the seismic isolator or support element 1.

As the thickness Z decreases, it is useful to use a core 18 having a higher density since, if subjected to bending, the core 18 is progressively more compressed.

Also in the case of the first layers 16, they are interspersed with a plurality of second layers 7.

The adhesion between first layers 6, 16 and second layers 7 or between the skins 17 and the core 18 of the first layers 16 and, subsequently, with the second layers 7 takes place through the use of adhesive means.

Such adhesive means may comprise, in one version of the invention, binder layers composed of solvent-based or water-based or diluent-free adhesives or paints. In this way, excellent sealing results are obtained, while using materials that are also able to respect the environment.

According to an embodiment, a first layer 16 can be made from a sandwich having an overall thickness of 17 mm, for a length of the plate or of the layer equal to 1.5 m. In this case, the sandwich has the following characteristics: weight equal to 4.3 Kg / m <2> and, if subjected to a load equal to 1000N / m2, it presents a deflection of 30 mm (possibly with a safety factor equal to 5.7).

Comparing a similar situation (load equal to 1000 N / m <2>), a traditional steel plate, having a thickness of 5 mm, has a weight equal to 39 Kg / m <2>, a deflection of 30 mm and a safety factor equal to 3.

It can thus be seen that the present invention performs much more efficient and effective performances than known solutions. Furthermore, since the type of response is not linked to the particular structure (understood as the number or size of the layers) of the isolator device 1, but varies according to the type of dynamic stress (thanks to the presence inside the device of a material in able to vary its mechanical behavior according to the force to which it is subjected), the use of the present invention is much safer for the constructions or structures to which the isolator device 1 is installed. At the bases 3,4, the isolator device 1 and / or the seismic isolator 1A can comprise plates 20. These plates 20 have a greater thickness than that of a first layer 6, 16 or of a second layer 7. These plates are made of composite material or steel. These plates 20 have holes for fixing the isolator device 1 and / or the seismic isolator 1A to the intermediate supports 21, placed between the plate 20 and the foundations F and / or the superstructure S of the building.

The fixing between plates 20 and intermediate supports 21 can take place by means of suitable screws. These intermediate supports 21, in a version of the invention illustrated for example in Figure 3, may have a recessed footprint for housing the plates 20 and / or the seismic isolator 1A.

In a still further version of the invention, for example illustrated in Figures 4 and 5, the isolator device 1 and / or the seismic isolator 1A can comprise at least one hole 22 which can remain empty for the entire life of the work or, times, be filled with lead to increase the damping capabilities of the system.

The at least one hole 22 can have a cylindrical shape and extend from the base 3 towards the inside of the isolator device 1 and / or of the seismic isolator 1A.

Furthermore, at the base 3, closing means 22b may be present, to close the access to the hole 22.

A possible method for manufacturing the isolator device 1 comprises the following steps:

preparation of a first layer 6, 16,

application on a surface of the first layer 6, 16 of an adhesive medium,

drying of the adhesive medium,

repetition of the above steps for each first layer 6, 16,

molding of this plurality of first layers 6, 16 with the material constituting the second layers 7, obtaining the multilayer structure.

Furthermore, following or in a contextual manner, a molding phase of the external envelope 8 may be envisaged.

The aforementioned molding step includes the vulcanization of the material that makes up the second layers 7 and / or of the outer casing 8, this vulcanization being able to couple the structure of the main body 2.

A further step that can be included in the aforementioned method includes a cleaning step of the first layers 6, 16, through the use of special solvents, before the application step of the adhesive medium.

Further steps may include the application of one or more plates 20 and their attachment to at least one intermediate support 21.

Finally, the isolator device 1, possibly equipped with a plate 20 and / or with an intermediate support 21, is applied to the construction in question, for example interposed between the foundations F and the superstructure S.

As said, according to the present invention there is at least one deformation sensor 50.

An example of a deformation sensor 50, such as a polymeric chromatic deformation sensor, will be described below.

In one version of the invention, the chromatic deformation sensor is of the photonic crystal type (PCs) or containing PCs. In this type of sensor, the optical properties of the sensor are governed by the periodicity of the refractive index. PCs are composed of dielectric or semidielectric nano structures that influence the propagation of electromagnetic waves, possessing photonic bands accessible for some frequencies and forbidden for others.

According to the law of Bragg and Snell (Fig. 13), the wavelength of the light reflected by the PC (and therefore the color of the PC) also depends on the interplanar distance D of the diffraction grating of the PC. By changing the interplanar distance of the PC diffraction grating, the wavelength of the light reflected by the PC and therefore its color changes.

Therefore, by applying the sensor 50 on the external lateral surface 5 of the isolator device 1, a deformation of the latter involves a deformation of the sensor (proportional to it), which assumes a color whose wavelength depends on the deformation reached by the sensor itself . According to the present invention, the color of the at least one sensor 50 applied to the deformed isolator device provides information about the extent and / or direction of the deformations undergone by the device 1. This characteristic makes the PCs ideal for monitoring, in a reversible or permanent way. , the deformations undergone by structural elements and / or constructions.

According to the present invention, depending on the nature of the colorimetric sensor and following the deformation of the isolator device 1 to which it is applied, the deformation colorimetric sensor can undergo:

- permanent and irreversible deformation (in this version of the invention, the sensor is suitable for permanent monitoring of structural elements subject to "fatigue" damage). In this case, the sensor 50 remains permanently deformed (and therefore of a different color) after the isolating device has recovered its original shape;

- a reversible deformation that can be recovered (in this version of the invention, the sensor 50 is suitable both for monitoring elements subject to cyclic deformations, and for detecting any non-permanent deformations of the device - after the cessation of the external deformation force ). In this case, in fact, if the device recovers its initial shape without maintaining residual deformations, the sensor 50 also recovers its original shape (and therefore the initial color) - after the isolator device has recovered its original shape - and therefore demonstrates the absence of residual deformations of the device (after the end of the earthquake, for example). Conversely, the “irreversible” sensor would remain deformed and colored (at the maximum deformation reached) even if the device recovered its initial shape (and therefore could not give evidence of any residual permanent deformations of the device).

In one version of the invention, PCs belong to the type of solid materials consisting of colloidal crystals inserted inside polymeric matrices, however the invention thus conceived includes all materials that change color with their deformation (not only PC), synthesized, constructed, produced, printed, etc. in any way and with any manufacturing technology (for example vertical deposition, sol gel, electrostatic repulsion, self-assembly by capillary force, lithography and nanocasting, sputtering, chemical and physical vapor deposition, etc ...) and subsequently applied on the surface of an isolator device 1. In this case the manufacturing techniques can be various, the important thing is that the deformation of the sensor 50 is integral and can quantify that of the device 1.

In a version of the invention, the PCs to be applied to the isolator device are of the thin film type deposited on a flexible elastomeric support (e.g. fluoroelastomer) using spheres of the silica or polystyrene type (with a diameter from 100 nm to 1000 nm) inserted into the interior of an elastomeric matrix of the polydimethylsiloxane (PDMS) type (for example by infiltrating the spheres with a PDMS solution, subsequently cross-linked by heat or UV rays).

In another version of the invention, the PCs to be applied to the isolator device are of the particle type consisting of a rigid core, of the polystyrene-poly (methyl methacrylate) type covered by an outer shell composed of a soft matrix of the poly (methyl methacrylate) type. ethyl acrylate).

In another version of the invention, the PCs to be applied to the isolator device are of the high refractive index nano particle type (of the ZrO2 nano particle type) inserted inside an elastic and flexible matrix capable of supporting high deformations (such as “slide ring” elastomers).

In one version of the invention, the strain sensor 50 is a chromic strain sensor applied to the surface of the isolator device and is of the inverse photonic crystal (IOPC) type, in which the dielectric or semidielectric nano structures that influence the propagation of electromagnetic waves are replaced by voids within the polymer matrix. The periodic structure of the voids of the IOPC modulates the propagation of electromagnetic waves within the material, creating photonic bands that are accessible for some frequencies and prohibited for others. According to the law of Bragg and Snell (Fig. 13), the wavelength of the light reflected by the IOPC (and therefore the color) also depends on the interplanar distance D of the diffraction grating of the IOPC. By changing the interplanar distance of the IOPC diffraction grating, the wavelength of the light reflected by the IOPC changes and therefore its color.

In general, IOPCs are made starting from PCs, subsequently removing the nanostructures from the matrix (thus leaving a periodic lattice made up of voids). In one version of the invention, IOPCs are obtained by creating a submicrometric crystalline structure of polymethylmethacrylate (PMMA) spheres within a silicone-type matrix and subsequently dissolving the PMMA-type spheres with a suitable solvent such as acetone.

The strain sensors 50, made with PCs, with IOPC or with any other material that changes color with deformation (and / or synthesized, constructed, produced, printed, etc. in any way and with any technology), can be applied to the isolator device:

- in any shape and size;

- in any number;

- in any position in the device (horizontal, vertical, oblique, center, etc.).

The possible methods for applying the deformation sensors 50 on the isolator device are:

- The co-vulcanization and / or hot co-crosslinking of the color sensors together with the isolator device during the molding of the device (using any adhesion agent),

- The vulcanization and / or hot crosslinking of the color sensors on the surface of the isolator device after the molding of the device (using any adhesion agent),

- The adhesiveness and / or cold crosslinking of the color sensors on the surface of the isolator device after molding the device (using any adhesion agent),

- The physical, chemical and / or mechanical anchoring of the sensors 50 on the surface of the isolator device after molding the device (using any anchoring technique),

In this way, a deformation (dimensional variation) of the isolator device 1 entails a deformation (dimensional variation) of the sensor 50 proportional to the first, with a consequent variation of the wavelength of the light reflected by the sensor 50 (which can therefore be correlated to the deformation of the isolator device 1). The wavelength variation can fall both in the visible spectrum, and in the infrared or ultraviolet spectrum.

A simplified and demonstrative example of the technique envisaged by the present invention will be set forth below, for example relating to chromatic deformation sensors.

Consider the situation described in Figure 12 (isolating device on the surface of which a deformation sensor 50 is applied in a vertical position, such as a chromatic deformation sensor and which is deformed by an external shear force F perpendicular to the surface of the chromatic sensor): for simplicity of calculation, the isolator device will be idealized as a parallelepiped of height L on the vertical (right) side of which the chromatic deformation sensor is applied in the form of a one-dimensional strip of length M (Figure 14).

From trigonometry it appears that:

Knowing the length M of the chromatic deformation sensor (hereinafter abbreviated with the abbreviation SC), the height L of the parallelepiped (idealized device) and the lateral displacement x of the parallelepiped itself, it is possible to obtain the length M 'of the deformed strip of SC (directly proportional to x): the SC strip therefore takes on a specific color (of wavelength λE) when the insulator reaches a specific shear deformation γE, thus acting as a chromatic deformation sensor. Recalling that L is the total height of the device (given by the sum of the total height of layers 6, 7), it results:

This means that a shear deformation of the device equal to γE corresponds to one

tensile strain on the SC strip equal to

According to the available literature data, the current SC technology allows

obtain chromatic variations for much lower X deformations Suppose then that the chromatic sensor strip of length M is actually (as visible in figure 15) made up of two co-vulcanized polymeric materials: the first (visible in the left part of figure 15) consisting of the SC with length M1, thickness d, width w and elastic modulus of traction E1 (which assumes a color of wavelength λE at ∆M <1> = X); the other (visible in the right part of figure 15), from a matrix of length M2, thickness d, width w and elastic tensile modulus E2 (which does not undergo chromatic transition).

The two strips have the same section A (= w x d) and the system can be modeled <as two rubber bands in series, from which it results that:>

The tensile strain of the sensor (SC matrix) corresponds to a shear strain of the device equal to γE. By hypothesis the strip of SC assumes a color of wavelength λE at the deformation X.

From Eq. 2) it appears that:

From Eq. 4) it appears that:

Therefore:

The elastic modules E1 and E2 are therefore linked by a constant of proportionality C as a function of the shear deformation of the device (a), of the initial dimensions of the strips of SC and matrix (M1 and M2) and of the elongation at which the strip of SC undergoes chromatic variation (X).

By designing the materials so that the elastic modulus of the SC strip is C times that of the matrix, it is possible to obtain a sensor that undergoes a chromatic variation (assuming a color of wavelength λE) when the device has reached a deformation of cut equal to γE.

Example

Consider an insulator 1 with an external diameter of 500 mm, L = 226 mm, T = 126 mm and H = 100 mm and apply a polymeric sensor 50 to the surface of the device, in a vertical position with respect to its base. two-component chromatic compound consisting of the SC with length M1 = 40 mm and elastic modulus E1 and the matrix with length M2 = 35 mm and elastic modulus E2 = 0.4 MPa (M = 75 mm, i.e. about 1 / 3L). The sensor is applied along the vertical axis of the device (as in Fig. 12 and 14), so that the shear deformation of the device corresponds to a tensile deformation of the sensor. Also suppose that the sensor assumes a color of wavelength λ <E> when γ <E> = 2. So:

Based on the available literature data, assume that the SC undergoes a chromatic variation at the wavelength λE when ∆M1 = X = 0.2 (ie at 20% of <deformation). So:>

Therefore, by designing the materials so that the elastic modulus of the strip SC of length M1 is about 1.7 MPa and that of the matrix of length M2 is 0.4 MPa, it is possible to obtain a sensor that undergoes a chromatic variation (assuming a color of wavelength λE) when the device 1 has reached a shear deformation equal to γE = 2.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept.

Furthermore, the features described for an embodiment of the invention may also be present in other embodiments described here, without thereby departing from the scope of protection conferred by the present invention.

Furthermore, all the details can be replaced by other technically equivalent elements. In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements without thereby departing from the scope of the protection of the following claims.

Claims (14)

CLAIMS 1. Isolating device (1), such as for example a seismic isolator (1A) or a support element (1B) for constructions, for example buildings, bridges, large structures, infrastructures, etc. o non-structural works, for example pedestals for artistic works, for example statues or similar, for furniture, for industrial machinery, etc., equipped with an overlying structure, to isolate or separate or distance the overlying structure of said building and a part of said construction integral with the foundations or with the ground in order to dissipate and / or absorb the forces or energy generated by an earthquake or by a dynamic stress to which said construction is subjected, in which said isolating device (1) comprises a plurality of first layers (6, 16) and a plurality of second layers (7), in which said first layers (6, 16) and said second layers (7) are interposed or interposed with respect to each other, characterized by the fact that said second layers (7) comprise a material having a mechanical behavior which varies according to the type and / or intensity of the forces or energy generated by an earthquake or by a dynamic stress to which the device is olator (1) is subjected to and by the fact that said isolator device (1) comprises at least one deformation sensor (50) capable of providing qualitative and / or quantitative information relating to the characteristics of said earthquake or said dynamic stress to which said construction is subjected and / or said isolator device (1). Isolator device (1) according to claim 1, wherein said at least one deformation sensor (50) comprises one or more chromatic deformation polymeric sensors, such as for example one or more deformation colorimetric sensors containing photonic crystals (PCs) and / or inverse photonic crystals (IOPC) and / or solid materials consisting of colloidal crystals inserted inside a polymeric matrix, and / or one or more sensors of the thin film type deposited on a flexible elastomeric support, such as for example fluoroelastomer, and / or for example with spheres of the silica or polystyrene type inserted inside an elastomeric matrix of the polydimethylsiloxane (PDMS) type, and / or one or more colorimetric deformation sensors of the particle type consisting of a rigid core, of the polystyrene type - poly (methyl methacrylate) coated by an outer shell composed of a soft matrix of the poly (ethyl acrylate) type, and / or of the high refractive index nano particle type (de l type of nano particles of ZrO2) inserted inside an elastic matrix capable of withstanding high deformations, for example of the "slide ring" elastomer type, and / or one or more deformation colorimetric sensors composed of two polymeric materials vulcanized, adhesive or bonded, for example a sensor SC and another sensor with polymeric matrix) such that the sensor SC comprises an elastic modulus C times greater than the elastic modulus of the other polymeric matrix sensor, for example so as to obtain a sensor (50) capable of undergoing a chromatic variation of wavelength λE when the device has reached a shear deformation equal to γE and / or one or more polymeric chromatic deformation sensors, such as for example one or more colorimetric sensors of deformation containing inverse photonic crystals (IOPC), such as for example those comprising micrometric spheres of the type comprising polymethylmethacrylate (PMMA) within a matrix of the si icon, in which said PMMA-type spheres are subsequently dissolved with a suitable solvent, and / or at least a material capable of changing color following their deformation and / or in which said at least one deformation sensor (50) is applied to an external lateral surface (5) of said isolator device (1). 3. Isolator device (1) according to claim 2, wherein said one or more chromatic deformation polymeric sensors are capable of being deformed by modifying the color and / or wavelength of the light reflected by them in a permanent and irreversible manner or reversibly. 4. Isolator device (1) according to any one of the preceding claims, in which said deformation colorimetric sensors are synthesized, constructed, produced, printed, etc. in any way and with any technology, such as vertical deposition, sol gel, electrostatic repulsion, self-assembly by capillary force, lithography and nanocasting, sputtering, chemical and physical vapor deposition, etc. 5. Isolating device (1) according to claim 1, wherein said second layers (7) comprise a non-Newtonian material or fluid, wherein said material having a mechanical behavior which varies according to the type and / or intensity of the forces or the energy generated by an earthquake or by a dynamic stress to which the isolator device (1) is subjected is called a non-Newtonian material or fluid and / or in which said non-Newtonian material or fluid is of the type having a "time independent ", Comprising a material having a pseudoplastic nature (in which case the shear strength decreases as the shear strain rate increases), such as a solution of a polymer, such as a solution of a polymer and / or a colloidal dispersion, or a material having dilating nature and / or a liquid dispersion of synthetic gum arabic such as tragacanth, gum arabic, sodium alginate, methylcellulose or in which said non-Newtonian material or fluid is of the type having a "time dependent" behavior, comprising a material having a thixotropic nature or a rheopectic or dilating material, such as an elastomer, a viscous silicone liquid, silicone marketed under the name "Silly Putty" or a matrix foam material polymer. 6. Isolator device (1) according to any one of the preceding claims, wherein said second layers (7) are made entirely of said non-Newtonian material or fluid or wherein said second layers (7) comprise said non-Newtonian material or fluid as a dopant within a matrix of a polymeric nature, comprising at least one polymer such as a natural or synthetic elastomer and / or a mixture of natural and / or synthetic elastomers, or rubber, or within a matrix of a non-polymeric nature. 7. Isolator device (1) according to any one of the preceding claims, in which said first layers (6, 16) are made of a metallic material, such as steel, or of a composite material or of a polymeric material, and / or in which said composite material comprises a matrix and a plurality of reinforcing elements or fibers, carbon fibers, glass fibers, ceramic fibers, aramid fibers or kevlar fibers or natural fibers, for example flax and / or hemp fibers, and / or wherein said plurality of reinforcing elements is free or embedded in the matrix or is in the form of a sheet or fabric or a plurality of multilayer fabrics, and / or in which said matrix or said polymeric material comprises a polymeric material, an elastomer or a plastic material or a thermoplastic polymer, Nylon or ABS, or a thermosetting polymer, an epoxy resin or a polyester or a phenolic resin or a mixture thereof and / or in which said matrix comprises a chemical / physical agent of process or necessary to confer certain properties to the material, a cross-linking agent, antioxidant, antiozonant, accelerator, activator, or inert fillers, active fillers, photosensitive, heat-sensitive materials, adhesion promoters, flame-retardant agents, etc., or a mixture thereof . 8. Isolator device (1) according to any one of the preceding claims, comprising said first means (6) made of a composite material or a polymeric material and said second layers (7), in which said second layers (7) are made in the same composite or polymeric material of said first layers (6), with the addition of the non-Newtonian material or fluid or comprising first layers (16), which have a sandwich structure comprising a core (18) enclosed by two surfaces or hides or skins (17), parallel to the bases (3, 4), wherein said surfaces or skins (17) comprise a composite material comprising a matrix and a plurality of reinforcing elements or fibers, for example glass fibers or carbon or kevlar or ceramic or aramid and / or in which said core (18) is made of a foam material, a thermosetting cross-linked polymer produced in the presence of a blowing agent, the polyurethane foam, or a honeycomb material (a honeycomb), for example a metal or plastic material having a honeycomb structure (cells), in alveolar aluminum, alveolar polycarbonate, alveolar polypropylene, etc ... 9. Isolator device (1) according to any one of the preceding claims, consisting of a main body (2) of a substantially geometric solid or prism or cylinder shape, comprising two bases (3, 4), substantially parallel to each other and having a polygonal shape or cylindrical, and a lateral surface (5), having a tubular conformation or comprising a series of lateral faces, in which said first layers (6, 16) and said second layers (7) are substantially parallel to each other and to said bases (3, 4). 10. Isolator device (1) according to any one of the preceding claims, comprising an outer casing (8) made of natural or synthetic elastomer material and / or of a mixture of natural and / or synthetic elastomers or of a material such as rubber and / or comprising adhesive means, for example an adhesive or a layer or a water-based paint, placed or applied between said first layers (6, 16) and said second layers (7) or between said surfaces or skins (17) and said core (18) and said second layers (7) and / or comprising at least one plate (20), placed in correspondence with at least one of said bases (3, 4) and / or at least one intermediate support (21). Method for manufacturing an isolating device (1), such as a seismic isolator (1A) or a support element (1B) according to any one of claims 1 to 15, comprising the following steps: preparation of a first layer (6, 16), application on at least one surface of the first layer (6, 16) of an adhesive medium, drying of the adhesive medium, repetition of the aforementioned steps for each first layer (6, 16), preparation of a plurality of second layers (7), in which said second layers (7) comprise a material having a mechanical behavior which varies according to the type and / or intensity of the forces or energy generated by an earthquake or dynamic stress to which the isolator device (1) is subjected, alternate a first layer (6, 16) with a second layer (7), molding of a plurality of first layers (6, 16) with the material of said plurality of second layers (7) interposed or spaced between said first layers (6, 16) and / or so as to obtain an external envelope (8), providing at least one deformation sensor (50) and applying said at least one deformation sensor (50) on an external lateral surface (5) of said isolator device (1). Method according to claim 11, wherein said molding step comprises a vulcanization step of the material which composes said second layers (7) and / or said outer casing (8). 13. Method according to claim 11, wherein said step of preparing said first layers (6, 16) comprises a preliminary step of cleaning said first layers (6, 16) by using suitable solvents, and / or comprising a step of applying one or more plates (20) and / or fixing them to at least one intermediate support (21). Method according to claims 11, wherein said application of said at least one deformation sensor (50) takes place by: hot co-vulcanization and / or co-crosslinking of said at least one sensor (50) with said isolator device (1) during molding of said isolator device (1) by means of an adhesion agent, or hot vulcanization and / or crosslinking of said at least one sensor (50) after molding of said isolator device (1) by means of an adhesion agent, or cold bonding or crosslinking of said at least one sensor (50) after molding of said isolator device (1) by means of an adhesion agent, or physical, chemical and / or mechanical anchoring of said at least one sensor (50) after molding of said isolator device (1) by means of an adhesion agent.