Bi-directional strain intelligent aggregate based on patch antenna, monitoring and sensing system and method

Abstract

The present invention relates to a two-way strain intelligent aggregate, a monitoring and sensing system and method based on a patch antenna. The overall structure of the intelligent aggregate is encapsulated by a cement-based protective layer, and further includes a radiation patch component, a movable radiation patch component, a coupled radiation patch component, a transmission rod, and a radio frequency identification chip carrying the intelligent aggregate coding and position information; the radiation patch component is closely attached to the movable radiation patch component, and the upper and lower ones overlap to form a short circuit with mutual dislocation; an elastomer is filled between the radiation patch component and the coupled radiation patch component; one end of the transmission rod is fixed to the movable radiation patch component, and the other end extends out of the protective layer and is fixed to the cement-based protective layer; the radio frequency identification chip is connected to the radiation patch component through a provided microstrip feeder line, and is used to activate the resonance of the radiation patch in two planar directions and the coupled resonance in the vertical direction. Compared with the prior art, the present invention can realize passive wireless monitoring of the two-way strain and temperature inside the concrete.

Description

Technical Field

[0001] The present invention relates to the field of structural health monitoring, and in particular to a two-way strain intelligent aggregate, a monitoring and sensing system and method based on a patch antenna. Background Art

[0002] As an important building material, concrete has been widely used in the field of civil engineering. Concrete itself is a building material with good durability. However, during long-term use, due to the effects of external environments and loads and other factors, the concrete material will deteriorate, posing a potential hazard to the safe and reliable operation of the structure. Therefore, during the entire life cycle of a concrete structure, it is necessary to sense the deformation state of the concrete structure and environmental factors affecting durability, so as to timely detect potential structural safety hazards and take necessary measures to ensure the safe and reliable use of the structure.

[0003] In recent years, concrete intelligent aggregates with advantages of locality and distribution have been gradually applied to the monitoring of internal damage of concrete. An intelligent aggregate refers to encapsulating a sensing unit used for concrete monitoring to make it an intelligent component that can be implanted into concrete, which not only has the functions of ordinary aggregates but also can realize the perception of internal information of concrete.

[0004] However, current intelligent aggregates still require continuous power supply and cables for signal transmission, and it is difficult to achieve synchronous sensing of multiple parameters inside concrete, which limits their application in actual engineering.

[0005] Therefore, it is necessary to design a passive wireless intelligent aggregate suitable for multi-directional strain and multi-parameter sensing inside concrete to overcome its dependence on cables and power supplies and realize wireless monitoring of multiple parameters inside concrete. Summary of the Invention

[0006] The purpose of the present invention is to provide a two-way strain intelligent aggregate, a monitoring and sensing system and method based on a patch antenna to achieve passive wireless monitoring of two-way strain and temperature inside concrete, thereby overcoming the defects of the existing technologies described above.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] According to a first aspect of the present invention, there is provided a two-way strain intelligent aggregate based on a patch antenna, the overall structure of which is encapsulated with a cement-based protective layer. The intelligent aggregate further includes a radiation patch assembly, a movable radiation patch assembly, a coupled radiation patch assembly, a transmission rod, and a radio frequency identification chip carrying the intelligent aggregate code and position information.

[0009] The radiation patch component is closely attached to the movable radiation patch component, and partially overlaps to form a short circuit with mutual dislocation; an elastomer is filled between the radiation patch component and the coupled radiation patch component, which is used to be compressed or stretched when the intelligent aggregate generates vertical deformation to change the distance between the radiation patch component and the coupled radiation patch component, so as to change the corresponding resonant frequency for vertical strain monitoring; wherein, the vertical direction is perpendicular to the plane where the radiation patch component is located;

[0010] The radiation patch component, the movable radiation patch component, the coupled radiation patch component and the radio frequency identification chip are wrapped with a protective layer; one end of the transmission rod is fixed to the movable radiation patch component, and the other end extends out of the protective layer and is fixed to the cement-based protective layer, which is used to transfer the horizontal stress caused by the compression deformation at both ends when the intelligent aggregate is horizontally stressed to cause mutual dislocation between the movable radiation patch and the radiation patch; wherein, the horizontal direction is parallel to the transmission rod;

[0011] The radio frequency identification chip is connected to the radiation patch component through a microstrip feeder line, which is used to activate the resonance in two directions of the radiation patch plane and the vertical coupling resonance.

[0012] Preferably, the radiation patch component includes a substrate and a radiation patch, the movable radiation patch component includes a movable radiation patch and a movable substrate, the coupled radiation patch component includes a coupled radiation patch and a coupled substrate, and the substrate, the radiation patch, the movable radiation patch, the movable substrate, the coupled radiation patch, and the coupled substrate are placed in sequence as follows:

[0013] The radio frequency identification chip is welded on the upper surface of the substrate and is connected to the radiation patch through a microstrip feeder line; the lower surface of the substrate is electroplated with a completely covered copper layer, and the upper surface of the substrate is electroplated and attached to the radiation patch; the lower surface of the movable substrate is electroplated and attached to the movable radiation patch, the upper surface of the movable radiation patch is closely attached to the radiation patch, and the upper and lower overlaps form a short circuit with mutual dislocation; the lower surface of the coupled substrate is electroplated and attached to the coupled radiation patch, the upper surface of the coupled substrate is fixed to the lower surface of the protective layer, and an elastomer is filled between the coupled radiation patch and the radiation patch, which is used to be compressed or stretched when the intelligent aggregate generates vertical deformation to change the distance between the coupled radiation patch and the radiation patch;

[0014] One end of the transmission rod is fixed to the movable substrate, and the other end extends out of the protective layer and is fixed to the cement-based protective layer, which is used to transfer the compression deformation at both ends when the intelligent aggregate is horizontally stressed to cause mutual dislocation between the movable radiation patch and the radiation patch.

[0015] Preferably, the microstrip feeder is arranged at a set distance away from the center line of the radiation patch to activate the resonance modes of the radiation patch in two planar directions and the coupled resonance mode of the coupled radiation patch.

[0016] Preferably, filling particles are filled between the middle of the transmission rod and the cement-based protective layer to bear part of the vertical force and enable the transmission rod to move horizontally.

[0017] Preferably, the intelligent aggregate is also provided with a waterproof coating, which is arranged on the inner wall of the cement-based protective layer.

[0018] Preferably, the radiation patch, the movable radiation patch, the coupled radiation patch and the microstrip feeder are all made of copper.

[0019] Preferably, the substrate, the movable substrate and the coupled substrate are all RT5880 dielectric plates.

[0020] According to the second aspect of the present invention, a two-way strain intelligent aggregate sensing system based on a patch antenna is provided. The system includes intelligent aggregates buried inside a concrete structure and a reader for reading information from the radio frequency identification chips in the intelligent aggregates and performing data processing; the intelligent aggregates are the two-way strain intelligent aggregates based on a patch antenna according to any one of the above.

[0021] The reader includes:

[0022] A wireless transceiver module for receiving the multi-order resonance frequency offset signals sent by the intelligent aggregates;

[0023] A modulation and demodulation module for demodulating the signals received by the wireless transceiver module;

[0024] A digital processing module for decoupling and calculating the horizontal and vertical strains and temperature changes of the structure at the buried positions of the intelligent aggregates inside the concrete structure according to the corresponding relationship;

[0025] A control module for transmitting modulated electromagnetic wave signals of different frequencies to the intelligent aggregates buried inside the concrete structure to activate the radio frequency identification chips in the intelligent aggregates.

[0026] According to the third aspect of the present invention, a monitoring method for the intelligent aggregate sensing system is provided. The method includes the following steps:

[0027] 1) The control module transmits modulated electromagnetic wave signals of different frequencies to the intelligent aggregates buried inside the concrete structure; when the signal power received by the intelligent aggregates reaches the set threshold, the radio frequency identification chips are activated;

[0028] 2) After the RFID chip is activated, the antenna of the coupling patch generates an electric current and emits an electromagnetic wave signal carrying the tag number and measuring point position information. After being received by the wireless transceiver module and processed by the modulation and demodulation module, the tag number and position information corresponding to the intelligent aggregate are obtained;

[0029] 3) The digital processing module determines the resonant frequencies of each order of the coupling patch antenna by finding the emission frequencies of the electromagnetic waves of the reader when the signal emission power reaches the minimum values of each order during the activation of the RFID chip;

[0030] 4) When the intelligent aggregate buried inside the concrete generates horizontal strain, vertical strain, and environmental temperature changes, the size of the radiation patch and the dielectric constant of the substrate inside the intelligent aggregate change, the distance between the radiation patches changes, and the resonant frequencies of each order of the intelligent aggregate shift; by calculating the shift amounts of the resonant frequencies of each order of the intelligent aggregate, the bidirectional strain amounts and temperature change amounts of the concrete where the intelligent aggregate is buried are decoupled, realizing the synchronous monitoring of the bidirectional strain and temperature inside the concrete.

[0031] Preferably, in step 4), when the intelligent aggregate buried inside the concrete generates horizontal strain, vertical strain, and environmental temperature changes, the size of the radiation patch and the dielectric constant of the substrate inside the intelligent aggregate change, the distance between the radiation patches changes, and the resonant frequencies of each order of the intelligent aggregate shift, specifically:

[0032] When the intelligent aggregate generates horizontal deformation, a relative displacement occurs between the moving radiation patch and the radiation patch, which in turn causes a change in the longitudinal length of the combined radiation patch, resulting in a change in its longitudinal resonant frequency;

[0033] When the temperature inside the concrete changes, the dielectric constants of the substrate and the moving substrate change, and the length and width of the radiation patch and the moving radiation patch change, thus causing changes in both the transverse and longitudinal resonant frequencies of the combined radiation patch;

[0034] When the intelligent aggregate undergoes vertical deformation, the elastomer undergoes corresponding deformation, which in turn causes a change in the distance between the coupled radiation patch and the radiation patch, resulting in a corresponding change in the resonant frequency of the coupled radiation patch.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] 1) The radio frequency identification sensing technology with the advantages of passive wireless is combined with the embedding form of concrete sensors of intelligent aggregates. The coupled patch antenna sensing unit is encapsulated into a passive wireless intelligent element that can be embedded in concrete for monitoring. It does not require energy input through pre-installed batteries or wires, but receives electromagnetic waves from the transmitting and receiving antennas for energy input. By providing energy through electromagnetic waves, no power cord or battery is needed to supply energy to the sensing system. The sensing system is simpler and more flexible in layout, greatly reducing the labor for installing intelligent aggregates and the cost of the sensing system, and is less likely to fail under natural disasters.

[0037] 2) Through the stress transfer of the horizontal transmission rod and the vertical elastic body, based on the change of the resonant frequency among the radiation patch, the moving radiation patch, and the coupled patch, the perception of the two-way strain inside the concrete is realized.

[0038] 3) When two-way strain or temperature change occurs in the concrete structure at the embedding position of the intelligent aggregate, the multi-order resonant frequency of the coupled patch antenna inside the intelligent aggregate changes. According to the influence of the two-way strain inside the concrete and the embedding environment temperature on the multi-order resonant frequency of the coupled antenna, the synchronous monitoring of parameters such as two-way strain and temperature inside the concrete is realized, and the intelligent aggregate sensor has a temperature compensation function.

[0039] 4) Utilizing the resonant characteristics of the coupled patch antenna, microstrip line eccentric feeding is adopted to excite the multi-order resonant frequencies of the radiation patch, the moving radiation patch, and the coupled radiation patch. By measuring and decoupling the multi-order resonant frequencies, the sensing of the horizontal strain, vertical strain, and temperature change inside the concrete can be realized.

[0040] 5) Encapsulation protection structures such as protective layers, waterproof coatings, and cement-based protective layers can effectively protect the sensing antenna inside the intelligent aggregate from being affected by the corrosive environment inside the concrete, etc., and the encapsulation protection structure can endow the intelligent aggregate with good mechanical properties.

[0041] 6) A polymer elastic material with a certain elastic modulus is used as a support between the radiation patch and the coupled radiation patch, which can change the distance between the radiation patch and the coupled radiation patch when the intelligent aggregate is stressed, thereby changing its coupled resonant frequency.

[0042] 7) The radio frequency identification chip stores information such as the intelligent aggregate number and the embedding position inside the concrete. This information can be captured by the reader, thereby realizing the rapid positioning of the intelligent aggregate.

[0043] 8) Based on the corresponding relationship between the offset of the multi-order resonant frequency of the coupled patch antenna and multiple monitored variables within a fixed range, the monitoring of multiple different variables inside the concrete by a single sensing unit can be realized, especially suitable for the monitoring of strains in different directions inside the concrete, and has strong applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 FIG. is a schematic diagram of a two-way strain intelligent aggregate structure based on a patch antenna according to the present invention;

[0045] Figure 2 FIG. is a schematic diagram of a radiation patch feeding method;

[0046] Figure 3 FIG. is a schematic diagram of a two-way strain intelligent aggregate monitoring and sensing system structure based on a patch antenna according to the present invention;

[0047] Reference numerals: 1 - substrate, 2 - radiation patch, 3 - movable radiation patch, 4 - movable substrate, 5 - coupling radiation patch, 6 - coupling substrate, 7 - elastomer, 8 - protective layer, 9 - waterproof coating, 10 - cement-based protective layer, 11 - transmission rod, 12 - filling particles, 13 - microstrip feed line, 14 - radio frequency identification chip, 15 - reader, 1501 - wireless transceiver module, 1502 - modulation and demodulation module, 1503 - digital processing module, 1504 - control module. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0049] Embodiment

[0050] As shown in Figure 1 and Figure 2 , this embodiment provides an intelligent aggregate based on two-way strain and temperature perception, including a substrate 1, a radiation patch 2, a movable radiation patch 3, a movable substrate 4, a coupling radiation patch 5, a coupling substrate 6, an elastomer 7, a protective layer 8, a waterproof coating 9, a cement-based protective layer 10, a transmission rod 11, filling particles 12, a microstrip feed line 13, and a radio frequency identification chip 14 carrying the intelligent aggregate coding and position information.

[0051] The lower surface of the substrate 1 is copper-plated and completely covers the lower surface of the substrate 1. The radiation patch 2 is electroplated and attached to the upper surface of the substrate 1. The movable radiation patch 3 is electroplated and attached to the lower surface of the movable substrate 4, and the movable radiation patch 3 is placed on the upper radiation patch 2 so that the movable radiation patch 3 is in close contact with the radiation patch 2, overlapping up and down to form a short circuit, and the movable radiation patch 3 and the radiation patch 2 can move relative to each other.

[0052] The coupled radiation patch 5 is electroplated and attached to the lower surface of the coupling substrate 6, and the upper surface of the coupling substrate 6 is fixed to the lower surface of the protective layer 8. The space between the coupled radiation patch 5 and the radiation patch 2 is filled with a polymer material elastomer 7 having a certain elastic modulus. When the intelligent aggregate deforms vertically, the elastomer 7 can be compressed or stretched, and the distance between the coupled radiation patch 5 and the radiation patch 2 changes.

[0053] The protective layer 8 is made of high-strength carbon fiber material, which plays a role in supporting the force and protecting the internal patch antenna. The waterproof coating 9 uses epoxy resin to avoid the influence of moisture and corrosive media inside the concrete. The cement-based protective layer 10 uses UHPC ultra-high performance concrete material to encapsulate the whole intelligent aggregate, so that it has good mechanical properties when buried inside the concrete.

[0054] One end of the transmission rod 11 is fixed to the moving substrate 4, and the other end is fixed to the cement-based protective layer 10. When the intelligent aggregate deforms horizontally under force, the compressive deformation at both ends will be transmitted through the transmission rod 11, causing relative displacement between the moving radiation patch 3 and the radiation patch 2. Among them, the space between the middle of the transmission rod 11 and the cement-based protective layer 10 is filled with filling particles 12 to bear part of the vertical force and enable the transmission rod 11 to move horizontally.

[0055] The RFID chip 14 is soldered on the upper surface of the substrate 1 and is connected to the radiation patch 2 through the microstrip feeder 13. The microstrip feeder 13 is not at the center line of the radiation patch 2, but deviates by a certain distance to excite the resonant modes of the radiation patch 2 in two planar directions and the coupled resonant mode of the coupled radiation patch 5.

[0056] The transverse direction of the radiation patch 2 corresponds to one resonant mode, and the longitudinal direction corresponds to another resonant mode. The resonant frequencies of the two resonant modes are related to the size of the combined radiation patch and the dielectric constant of the substrate. When the intelligent aggregate deforms horizontally, a relative displacement occurs between the moving radiation patch 3 and the radiation patch 2, which in turn causes a change in the longitudinal length of the combined radiation patch, resulting in a change in its longitudinal resonant frequency.

[0057] When the temperature inside the concrete changes, the dielectric constants of the substrate 1 and the moving substrate 4 will change, and the lengths and widths of the radiation patch 2 and the moving radiation patch 3 will also change, so that the transverse and longitudinal resonant frequencies of the combined radiation patch both change.

[0058] When the intelligent aggregate deforms vertically, the elastomer 7 also undergoes corresponding deformation, which in turn causes a change in the distance between the coupled radiation patch 5 and the radiation patch 2, resulting in a corresponding change in the resonant frequency of the coupled radiation patch 5.

[0059] Through the measurement of the multi-order resonant frequencies of the bidirectional strain intelligent aggregate based on the patch antenna, the synchronous perception and monitoring of the horizontal strain, vertical strain, and temperature parameters inside the concrete can be decoupled and realized, and the intelligent aggregate sensor has a temperature compensation function.

[0060] In this embodiment, the materials of the radiation patch 2, the movable radiation patch 3, the coupled radiation patch 5, and the microstrip feeder 13 are all made of copper, and the substrates 1, the movable substrate 4, and the coupled substrate 6 are made of RT5880 dielectric substrates.

[0061] The intelligent aggregate is buried at the monitoring point inside the concrete structure, and the internal coupled patch antenna is fed in a way that the radio frequency identification chip 14 is connected to the eccentric microstrip feeder 13 to excite the multi-order resonant modes of the coupled patch antenna.

[0062] The encapsulation protection structures such as the protective layer 8, the waterproof coating 9, and the cement-based protective layer 10 of the intelligent aggregate can effectively protect the sensing antenna inside the intelligent aggregate from the influence of the erosive environment inside the concrete, etc., and the encapsulation protection structure can make the intelligent aggregate have good mechanical properties.

[0063] In the horizontal strain monitoring inside the concrete, the transmission rod 11 plays a role in transmitting the strain. When the horizontal deformation occurs at the measuring point, the transmission rod 11 transmits the relative displacement at both ends of the intelligent aggregate to the movable substrate 4 and the movable radiation patch 3, causing relative dislocation between it and the substrate 1 and the radiation patch 2. The movable radiation patch 3 is closely attached to the radiation patch 2 to form a combined patch antenna, and the longitudinal resonant frequency of this combined patch antenna is related to the overlapping length between the two radiation patches.

[0064] In the vertical strain monitoring inside the concrete, the elastomer 7 and the protective layer 8 play a role in transmitting the vertical strain. When the vertical deformation occurs at the measuring point, the intelligent aggregate is vertically stressed, which causes the elastomer 7 to be stretched or compressed, changing the distance between the connected radiation patch 2 and the coupled radiation patch 5, and then causing the change of the high-order resonant frequency of the coupled patch antenna. The change amount of the resonant frequency is related to the vertical strain at the buried position of the intelligent aggregate.

[0065] In the internal environmental temperature monitoring of the concrete, the change of temperature will cause the change of the dielectric constants of the substrate 1, the movable substrate 4, and the coupled substrate 6. And affected by the temperature change, the substrate 1 and the radiation patch 2, the movable substrate 3 and the movable radiation patch 4, and the coupled radiation patch 5 and the coupled substrate 6 will all undergo coordinated deformation, causing the change of the multi-order resonant frequencies of the coupled patch antenna.

[0066] It should be emphasized that the horizontal and vertical directions mentioned in the present invention are respectively the parallel direction of the transmission rod 11 and the vertical direction perpendicular to the transmission rod 11 (i.e., perpendicular to the plane where the vertical radiation patch 2 is located), which are not the traditional horizontal and vertical directions. In the actual monitoring application scenario, the two-way strain intelligent aggregate device of the present invention is buried according to the direction of the force to be monitored and sensed as required.

[0067] Next, a system embodiment of the present invention is given. An intelligent aggregate sensing system, as Figure 3 shown, includes intelligent aggregates buried at the monitoring point positions inside the concrete structure, and a reader 15 for wirelessly measuring the multi-order resonant frequencies of the coupling patch antennas inside the intelligent aggregates. Among them, the reader 15 includes:

[0068] A wireless transceiver module 1501 for receiving the multi-order resonant frequency offset signals sent by the intelligent aggregates;

[0069] A modulation and demodulation module 1502 for demodulating the signals received by the wireless transceiver module 1501;

[0070] A digital processing module 1503 for decoupling and calculating the structural horizontal and vertical strains and temperature changes at the positions where the intelligent aggregates are buried inside the concrete structure according to the corresponding relationship;

[0071] A control module 1504 for transmitting modulated electromagnetic wave signals with different frequencies to the intelligent aggregates buried inside the concrete structure to activate the radio frequency identification chip 14 in the intelligent aggregates.

[0072] Next, a method embodiment of the present invention is given. A monitoring method for the intelligent aggregate monitoring and sensing system, the method includes the following steps:

[0073] 1) The control module 1504 transmits modulated electromagnetic wave signals with different frequencies to the intelligent aggregates buried inside the concrete structure; when the signal power received by the intelligent aggregates reaches the set threshold, the radio frequency identification chip 14 is activated;

[0074] 2) After activating the radio frequency identification chip 14, the antenna of the coupling patch generates current and emits an electromagnetic wave signal with the tag number and the measuring point position information. After this signal is received by the wireless transceiver module 1501 and processed by the modulation and demodulation module (1502), the tag number and position information of the corresponding intelligent aggregate are obtained;

[0075] 3) The digital processing module 1503 determines the multi-order resonant frequencies of the coupling patch antenna by finding the transmission frequencies of the electromagnetic waves of the reader 15 when the signal transmission power reaches the minimum values of each order when activating the radio frequency identification chip 14;

[0076] 4) When the intelligent aggregate buried inside the concrete generates horizontal strain, vertical strain, and environmental temperature changes, the size of the radiation patch and the dielectric constant of the substrate inside the intelligent aggregate change, the distance between the radiation patches changes, and the resonant frequencies of each order of the intelligent aggregate shift; by calculating the shift amounts of the resonant frequencies of each order of the intelligent aggregate, the two-way strain and temperature change amounts of the concrete at the buried position of the intelligent aggregate are decoupled, and the synchronous monitoring of the two-way strain and temperature inside the concrete is carried out.

[0077] Among them, in step 4), when the intelligent aggregate buried inside the concrete generates horizontal strain, vertical strain, and environmental temperature changes, the size of the radiation patch and the dielectric constant of the substrate inside the intelligent aggregate change, the distance between the radiation patches changes, and the resonant frequencies of each order of the intelligent aggregate shift. Specifically:

[0078] When the intelligent aggregate generates horizontal deformation, a relative displacement occurs between the moving radiation patch 3 and the radiation patch 2, which in turn causes a change in the longitudinal length of the combined radiation patch, resulting in a change in its longitudinal resonant frequency.

[0079] When the temperature inside the concrete changes, the dielectric constants of the substrate 1 and the moving substrate 4 change, and the length and width of the radiation patch 2 and the moving radiation patch 3 change, so that the transverse and longitudinal resonant frequencies of the combined radiation patch both change.

[0080] When the intelligent aggregate undergoes vertical deformation, the elastic body 7 undergoes corresponding deformation, which in turn causes a change in the distance between the coupled radiation patch 5 and the radiation patch 2, causing a corresponding change in the resonant frequency of the coupled radiation patch 5.

[0081] The coupled patch antenna inside the intelligent aggregate is fed in a way that the radio frequency identification chip 14 is connected to the eccentric microstrip feeder 13 to excite multiple resonant modes of the coupled patch antenna.

[0082] The reader 15 transmits modulated electromagnetic wave signals to the intelligent aggregate at different frequencies. When the reader 15 transmits signals at a certain resonant frequency of the coupled patch antenna, the transmission power required to activate the radio frequency identification chip 14 will significantly decrease. By finding the electromagnetic wave transmission frequency that makes the threshold transmission power reach the minimum value, the multiple resonant frequencies of the coupled patch antenna inside the intelligent aggregate can be determined.

[0083] According to the multiple resonant frequencies of the coupled patch antenna inside the intelligent aggregate measured by the reader, decoupling can be performed to measure the horizontal and vertical strains of the concrete structure at the buried position of the intelligent aggregate, and the temperature at the monitoring point can be measured synchronously, so as to perform temperature compensation on the measured values of the two-way strain inside the concrete.

[0084] The encoded and location information of the intelligent aggregates carried in the radio frequency identification chip 14 is used to transmit a modulated electromagnetic wave signal to the intelligent aggregates by the reader 15, so as to identify the encoding of the intelligent aggregates and their embedded positions inside the concrete structure. When the reader 15 scans multiple intelligent aggregates embedded within the range of the concrete structure, the reader 15 can mark the bidirectional strain and temperature values at each monitoring point inside the concrete structure according to the encoding of each intelligent aggregate for monitoring.

[0085] Temperature self-compensation principle:

[0086] The intelligent aggregate in the present invention has two resonant modes, namely longitudinal and transverse, and also has a coupled resonant mode of the coupled radiation patch 5. The corresponding resonant frequency formulas are expressed as follows:

[0087]

[0088]

[0089]

[0090] In the formula, ΔT represents the change in the internal temperature of the concrete, and ΔL 水平向应变 , ΔL 竖向应变 respectively represent the relative displacements generated between the moving radiation patch 3 and the radiation patch 2, and between the radiation patch 2 and the coupled radiation patch 5 due to the internal strain of the concrete; and are respectively the coefficients of the longitudinal resonant frequency varying with temperature, the coefficient of the transverse resonant frequency varying with temperature, and the coefficient of the coupled resonant frequency varying with temperature, is the coefficient of the longitudinal resonant frequency varying with the horizontal strain of the concrete, is the coefficient of the coupled resonant frequency varying with the vertical strain of the concrete. All the above coefficients can be obtained by theoretical calculation.

[0091] By measuring the multi-order resonant frequencies (longitudinal resonant frequency, transverse resonant frequency, coupled resonant frequency) of the passive wireless intelligent aggregates, the synchronous perception and monitoring of the horizontal strain, vertical strain, and temperature parameters inside the concrete can be decoupled and realized, and the intelligent aggregate sensor has a temperature compensation function, without the need to additionally attach a temperature sensor to correct the temperature offsets of the longitudinal resonant frequency and the coupled resonant frequency.

[0092] As described above, the above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A two-way strain intelligent aggregate based on a patch antenna, characterized in that, The overall structure is encapsulated with a cement-based protective layer (10). The intelligent aggregate further includes a radiation patch assembly, a movable radiation patch assembly, a coupled radiation patch assembly, a transmission rod (11), and a radio frequency identification chip (14) carrying the intelligent aggregate code and position information; The radiation patch assembly is closely attached to the movable radiation patch assembly, and partially overlaps to form a short circuit with mutual dislocation; an elastomer (7) is filled between the radiation patch assembly and the coupled radiation patch assembly, which is compressed or stretched when the intelligent aggregate generates vertical deformation to change the distance between the radiation patch assembly and the coupled radiation patch assembly, thereby changing the corresponding resonance frequency for vertical strain monitoring; wherein, the vertical direction is perpendicular to the plane where the radiation patch assembly is located; The radiation patch assembly, the movable radiation patch assembly, the coupled radiation patch assembly, and the radio frequency identification chip (14) are wrapped with a protective layer (8); one end of the transmission rod (11) is fixed to the movable radiation patch assembly, and the other end extends out of the protective layer (8) and is fixed to the cement-based protective layer (10), which is used to transfer the compression deformation at both ends when the intelligent aggregate is deformed by horizontal force, causing mutual dislocation between the movable radiation patch (3) and the radiation patch (2); wherein, the horizontal direction is parallel to the transmission rod (11); The radio frequency identification chip (14) is connected to the radiation patch assembly through a microstrip feeder line (13) provided, which is used to activate the resonance in two directions of the radiation patch plane and the vertical coupled resonance.

2. The two-way strain intelligent aggregate based on a patch antenna according to claim 1, characterized in that, The radiation patch assembly includes a substrate (1) and a radiation patch (2), the movable radiation patch assembly includes a movable radiation patch (3) and a movable substrate (4), the coupled radiation patch assembly includes a coupled radiation patch (5) and a coupled substrate (6), and the substrate (1), radiation patch (2), movable radiation patch (3), movable substrate (4), coupled radiation patch (5), and coupled substrate (6) are placed in sequence, where: The radio frequency identification chip (14) is welded on the upper surface of the substrate (1) and is connected to the radiation patch (2) through a microstrip feeder line (13) provided; the lower surface of the substrate (1) is electroplated with a completely covered copper layer, and the upper surface of the substrate (1) is electroplated and attached to the radiation patch (2); the lower surface of the movable substrate (4) is electroplated and attached to the movable radiation patch (3), the upper surface of the movable radiation patch (3) is closely attached to the radiation patch (2), and the upper and lower overlaps form a short circuit with mutual dislocation; the lower surface of the coupled substrate (6) is electroplated and attached to the coupled radiation patch (5), the upper surface of the coupled substrate (6) is fixed to the lower surface of the protective layer (8), and an elastomer (7) is filled between the coupled radiation patch (5) and the radiation patch (2), which is compressed or stretched when the intelligent aggregate generates vertical deformation to change the distance between the coupled radiation patch (5) and the radiation patch (2); One end of the transmission rod (11) is fixed to the moving substrate (4), and the other end extends out of the protective layer (8) and is fixed to the cement-based protective layer (10), which is used to transfer the horizontal stress caused by the horizontal deformation of the intelligent aggregate during stress generation, so as to cause relative displacement between the moving radiation patch (3) and the radiation patch (2).

3. The two-way strain intelligent aggregate based on a patch antenna according to claim 2, characterized in that, The microstrip feeder (13) is set at a distance from the center line of the radiation patch (2) to activate the resonance modes of the radiation patch (2) in two planar directions and the coupled resonance mode of the coupled radiation patch (5).

4. A two-way strain intelligent aggregate based on a patch antenna according to claim 2, characterized in that, Filling particles (12) are filled between the middle part of the transmission rod (11) and the cement-based protective layer (10) to bear part of the vertical force and enable the transmission rod (11) to move horizontally.

5. The two-way strain intelligent aggregate based on a patch antenna according to claim 2, characterized in that, The intelligent aggregate is also provided with a waterproof coating (9) on the inner wall of the cement-based protective layer (10).

6. The bidirectional strain intelligent aggregate based on a patch antenna according to claim 2, wherein The materials of the radiation patch (2), the moving radiation patch (3), the coupled radiation patch (5) and the microstrip feeder (13) are all copper.

7. A two-way strain intelligent aggregate based on a patch antenna according to claim 2, characterized in that, The substrates (1), the moving substrate (4) and the coupled substrate (6) are all RT5880 dielectric substrates.

8. A two-way strain intelligent aggregate monitoring and sensing system based on a patch antenna, characterized in that, The system includes intelligent aggregates buried inside a concrete structure and a reader (15) for reading information from the radio frequency identification chips (14) in the intelligent aggregates and performing data processing; the intelligent aggregates are the patch antenna-based bidirectional strain intelligent aggregates according to any one of claims 1 to 7. The reader (15) includes: A wireless transceiver module (1501) for receiving the multi-order resonance frequency offset signals emitted by the intelligent aggregates; A modulation and demodulation module (1502) for demodulating the signals received by the wireless transceiver module (1501); A digital processing module (1503) for decoupling and calculating the horizontal and vertical strains and temperature changes at the positions where the intelligent aggregates are buried inside the concrete structure according to the corresponding relationship; A control module (1504) for transmitting modulated electromagnetic wave signals with different frequencies to the intelligent aggregates buried inside the concrete structure to activate the radio frequency identification chips (14) in the intelligent aggregates.

9. A method for the two-way strain intelligent aggregate monitoring and sensing system based on a patch antenna as described in claim 8, characterized in that, The method includes the following steps:[[]] 1) The control module (1504) transmits modulated electromagnetic wave signals with different frequencies to the intelligent aggregates buried inside the concrete structure; when the signal power received by the intelligent aggregates reaches the set threshold, the radio frequency identification chip (14) is activated; 2) After the radio frequency identification chip (14) is activated, the antenna of the coupled patch generates current and emits an electromagnetic wave signal carrying the tag number and the measuring point position information. After being received by the wireless transceiver module (1501) and processed by the modulation and demodulation module (1502), the tag number and position information of the corresponding intelligent aggregate are obtained; 3) The digital processing module (1503) determines the resonance frequencies of each order of the coupled patch antenna by finding the transmission frequencies of the electromagnetic waves of the reader (15) when the signal transmission power reaches the minimum values of each order when activating the radio frequency identification chip (14). 4) When the intelligent aggregate buried inside the concrete generates horizontal strain, vertical strain, and environmental temperature changes, the size of the radiation patch and the dielectric constant of the substrate inside the intelligent aggregate change, the distance between the radiation patches changes, and the resonant frequencies of each order of the intelligent aggregate shift; by calculating the shift amounts of the resonant frequencies of each order of the intelligent aggregate, the two-way strain and temperature change amounts of the concrete at the buried position of the intelligent aggregate are decoupled, and the synchronous monitoring of the two-way strain and temperature inside the concrete is carried out.

10. The method according to claim 9, wherein In step 4), when the intelligent aggregate buried inside the concrete generates horizontal strain, vertical strain, and environmental temperature changes, the size of the radiation patch and the dielectric constant of the substrate inside the intelligent aggregate change, the distance between the radiation patches changes, and the resonant frequencies of each order of the intelligent aggregate shift. Specifically: When the intelligent aggregate generates horizontal deformation, a relative displacement occurs between the moving radiation patch (3) and the radiation patch (2), which in turn causes a change in the longitudinal length of the combined radiation patch, resulting in a change in its longitudinal resonant frequency. When the temperature inside the concrete changes, the dielectric constants of the substrate (1) and the moving substrate (4) change, and the radiation patch (2) and the moving radiation patch (3) change in length and width, so that both the transverse and longitudinal resonant frequencies of the combined radiation patch change. When the intelligent aggregate undergoes vertical deformation, the elastomer (7) undergoes corresponding deformation, which in turn causes a change in the distance between the coupled radiation patch (5) and the radiation patch (2), causing a corresponding change in the resonant frequency of the coupled radiation patch (5).

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