CN107796543A - Strain-type micro gap monitoring device and fission calculation method - Google Patents
Strain-type micro gap monitoring device and fission calculation method Download PDFInfo
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Abstract
Invention is related to a kind of strain-type micro gap monitoring device, including gauge length crossbeam, cantilever beam pack, strain pack and built-in integrated signal conditioning unit.Gauge length beam erection the high face such as cantilever beam pack and separates from the both ends of gauge length crossbeam in the cantilever beam pack being arranged in pairs.Strain pack is fixedly connected with the bottom of cantilever beam pack, and strains electric bridge pattern of the pack according to the different fission width permissible value configuration strain pack estimated.Built-in integrated signal conditioning unit is embedded among gauge length crossbeam, is electrically connected with strain pack.The present invention can be on the premise of ensureing that binding structure to be measured is intact, the state of development of fission that is quick, accurate, detecting civil engineering structure exhaustive, avoids large scale structure from the generation of disaster accident such as being broken or collapse.
Description
Technical Field
The invention belongs to the technical field of civil and architectural engineering, and particularly relates to a strain type micro-gap monitoring device and a fission resolving method.
Background
In civil and architectural engineering, fission is the centralized embodiment that the damage inside the structure reaches the dangerous degree, the existence of fission is the primary factor of safety, and the generation and the expansion of fission directly destroy the integrity of the structure, cause the rapid change of the internal stress of the structure and cause the fracture or the collapse of the structure. Therefore, the fission detection is an effective method for evaluating the health condition of the civil construction structure, how to quickly, accurately and leaklessly detect the development condition of the fission is very important, and the occurrence of catastrophic accidents such as large-scale structure fracture or collapse can be avoided.
Most of the traditional fission detection methods are directed at concrete structures and mainly divided into a lossy method and a lossless method. The lossy method comprises the methods of slotting, punching and pressing water or wind, drilling and coring and the like; non-destructive methods include optical methods, ultrasonic detection methods, ballistic elastic wave methods, acoustic emission detection methods, photographic detection methods, fiber optic sensor network monitoring, sensor detection methods, and the like. The method comprises the steps of measuring the width of the existing fission by a light measuring method, a camera shooting method and a fission microscope method in a nondestructive method, measuring the depth of the fission by an ultrasonic velocity method and an impact elastic wave method, and measuring the fission by an acoustic emission method, an optical fiber sensing network and a sensor detection method.
Disclosure of Invention
The invention provides a strain type micro gap monitoring device and a fission calculating method aiming at the defects and problems in the prior art. The gauge length cross beams are erected on the cantilever beam assemblies which are arranged in pairs, and the cantilever beam assemblies are equal in height, opposite to each other and separated from two end parts of the gauge length cross beams. The method can quickly, accurately and leaklessly detect the fission development condition of the civil building structure on the premise of ensuring the integrity and the damage of the to-be-tested connection structure, and avoid the occurrence of disaster accidents such as large-scale structure fracture or collapse.
The technical scheme of the invention is as follows:
according to one aspect, the embodiment of the invention provides a strain type micro gap monitoring device which is characterized by comprising a gauge length beam, a cantilever beam group piece, a strain group piece and a built-in integrated signal conditioning unit; the gauge length cross beams are erected on the cantilever beam assemblies which are arranged in pairs, and the cantilever beam assemblies are equal in height, opposite to each other and separated from two end parts of the gauge length cross beams;
the strain gauge is fixedly connected with the lower end part of the cantilever beam gauge, and the strain gauge is configured with a bridge mode of the strain gauge according to different estimated fission width allowable values; the built-in integrated signal conditioning unit is pre-embedded in the gauge length beam and is electrically connected with the strain gauge.
Further, the bridge pattern of the strain gage elements comprises: full or half bridge or 1/4 bridge.
Preferably, the strain type micro gap monitoring device further comprises a fixing member for fixedly connecting the strain type micro gap monitoring device with the structure to be measured.
Further, little gap monitoring devices of strain gauge and the structure fixed connection that awaits measuring include:
a gauge length beam of the strain type micro-gap monitoring device is fixedly arranged on a vertical bisector of a path where fission of the structure to be detected can occur; or a gauge length beam of the strain type micro-gap monitoring device is fixedly arranged at a key detection position of the structure to be detected;
the structure to be tested comprises a concrete structure, a metal structure or a wood structure which is undergoing fission; or the structure to be tested comprises an existing old fissile concrete structure, a metal structure or a wood structure.
Furthermore, the built-in integrated signal conditioning unit comprises an instrument amplifying circuit, a filter circuit and a voltage stabilizing circuit, wherein the input end of the instrument amplifying circuit is connected with the output end of the strain gauge, and the output end of the instrument amplifying circuit conditions small measurement signals from the strain gauge through the filter circuit and then converts the conditioned small measurement signals into standard voltage signals to be output; the input end of the voltage stabilizing circuit is connected with a power supply, and the output end of the voltage stabilizing circuit is connected with the input end of the strain gauge.
Further, the fixing member includes a mounting flange, a bolt, and/or an epoxy-based adhesive fixing agent.
Preferably, a plurality of the micro gap monitoring devices form a micro gap monitoring array, and are configured on the corresponding plurality of fission possible occurrence paths or key detection positions on the structure to be detected according to different working conditions; and the plurality of micro gap monitoring devices are connected in a wired or wireless mode.
Preferably, a cable sealing plug connected with a cable is further arranged on the gauge length beam, the cable at one end of the cable sealing plug is electrically connected with the built-in integrated signal conditioning unit, and the cable at the other end of the cable sealing plug is connected with a peripheral data acquisition device or a power supply.
The embodiment of the invention further provides a strain type micro gap fission calculating method based on any strain type micro gap monitoring device, which specifically comprises the following steps:
estimating a path where fission is likely to occur or determining a key detection position;
determining the range of the monitoring device, and taking the range as the scale distance L of the sensitive unit;
determining the thickness h of a single cantilever beam piece, the length l of the single cantilever beam piece and the width b of the single cantilever beam piece in the cantilever beam assembly piece;
determining the rigidity of the cantilever beam sheet according to the fission or displacement generated in the gauge length of the sensitive unit;
determining the bending moment of the cantilever beam piece according to the rigidity of the cantilever beam piece;
determining the interface stress component of the surface of the cantilever beam sheet by combining the flexural section modulus of the cantilever beam;
and determining the surface strain of the cantilever beam sheet and the strain in the gauge length.
Wherein,
the cantilever beam piece has a rigidity of
The moment of the cantilever beam is
Flexural section modulus w of cantilever beam is bh2/6；
The interfacial stress component of the surface of the cantilever beam sheet is
Surface strain of cantilever beam sheet
Strain in gauge length epsilonL＝△x/L。
The invention has the technical effects that:
1. the embodiment of the invention provides a strain type micro-gap monitoring device, which is used for rapidly and accurately detecting the ongoing fission of a structure to be detected (such as a bridge and a pier) on the premise of not damaging the integrity of the structure to be detected, namely monitoring the dynamic change of the structure to be detected under the action of load. On the other hand, the existing fission is easier to generate dynamic change under the action of external force relative to the position where the existing fission does not occur, but the monitoring device is sensitive to both long-term slow fission and short-term low-frequency fission, so that the fission of the existing structure can be measured without damage.
The strain type micro-gap monitoring device provided by the embodiment of the invention can flexibly configure the bridge mode and the cantilever beam structure of the strain gauge according to the measurement requirement in the range of the allowable value of the measured position fission width, such as 1/4 bridge, half bridge and full bridge strain gauges.
2. The monitoring detection object of the monitoring device provided by the embodiment of the invention is not limited to a concrete structure, but also can detect a metal structure, a wood structure and the like, and the application range is wider.
3. The monitoring device comprises a gauge length beam, a cantilever beam group piece, a strain group piece and a built-in integrated signal conditioning unit. The design has simple structure, convenient installation and good environmental adaptability, and can work stably and reliably for a long time in all-weather and full-temperature range.
The compact construction brings about a good technical effect of easy maintenance in the later period, thus bringing about considerable economic benefits.
4. The detection object of the monitoring device provided by the embodiment of the invention is not limited to a concrete structure, but also can detect a metal structure, a wood structure and the like, and the application range is wider.
5. The embodiment of the invention can be flexibly combined and configured aiming at different application scenes, namely, each monitoring device is used as a sensitive unit under the background of working condition detection requirements, and a plurality of sensitive units can be configured at a plurality of key parts on a structure to be detected, thereby improving the efficiency of crack problem investigation and providing powerful technical support for quickly positioning problems.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a schematic view illustrating an exemplary structure of a strain type micro gap monitoring device according to an embodiment of the present invention.
FIG. 2 is a schematic view of a partial structure of a strain type micro gap monitoring device according to an embodiment of the present invention.
The wheatstone bridge strain gage connection mode in the embodiment of fig. 3 is schematically illustrated.
Fig. 4 is a schematic diagram of an internal structure and an operating principle of a signal conditioning unit according to an embodiment of the present invention.
FIG. 5 is a flow chart of a strain type micro gap fission solution method of the invention.
FIG. 6 is a schematic diagram of a strain-type micro-gap fission solution model of the invention.
Description of reference numerals:
1-gauge length beam, 2-cantilever beam assembly, 3-mounting flange, 4-first strain gauge,
5-built-in integrated signal conditioning unit; 6-cable sealing plug, 7-cable, 8-mounting hole,
9-the second strain gauge, 10-the third strain gauge, and 11-the fourth strain gauge.
Detailed Description
In civil and architectural engineering, fission is the centralized embodiment of the damage of the structure to the dangerous degree and is the primary factor influencing safety, and the generation and the expansion of fission directly damage the integrity of the structure, cause the rapid change of the internal stress of the structure and cause the fracture or the collapse of the structure.
The inventors have found that, although methods of assessing the health of civil structures exist today, most are directed to the detection of some fission that is occurring or is about to occur. How to detect the development condition of fission quickly, accurately and without leakage is very important, and the occurrence of disaster accidents such as large-scale structure fracture or collapse can be avoided.
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative only and should not be construed as limiting the invention.
Fig. 1 is a schematic view illustrating an exemplary structure of a strain type micro gap monitoring device according to an embodiment of the present invention. As shown in fig. 1, the strain type micro gap monitoring device provided in the embodiment of the present invention includes a gauge length beam 1, a cantilever beam assembly 2, a strain assembly, and a built-in integrated signal conditioning unit 5. The cantilever beam assembly pieces 2 can contain different numbers of cantilever beam pieces according to different measurement requirements. The strain gauge may include a different number of strain gauges according to the detection requirement, and the example in fig. 1 is a strain type micro gap monitoring device including four strain gauges. The first strain gauge 4, the second strain gauge 9, the third strain gauge 10 and the fourth strain gauge 11 are fixed on the front and back corresponding sides of the two cantilever beams in an adhering mode and connected into a Wheatstone bridge mode. Examples of strain gauges in fig. 1 are four metal strain gauges R1, R2, R3, R4.
The gauge length crossbeam 1 is erected on the cantilever beam group pieces 2 arranged in pairs, and the cantilever beam group pieces 2 are equal in height, opposite to each other and separated from two end parts of the gauge length crossbeam 1. The strain gauge is fixedly connected with the lower end part of the cantilever beam gauge, and the strain gauge configures the bridge mode of the strain gauge according to the estimated different allowable values of the fission width; the built-in integrated signal conditioning unit 5 is pre-embedded in the gauge length beam 1 and is electrically connected with the strain gauge.
The bridge pattern of the strain gage comprises: full or half bridge or 1/4 bridge. The strain type micro gap monitoring device further comprises a fixing component which is used for fixedly connecting the strain type micro gap monitoring device with a structure to be detected. The structure to be tested referred to herein includes a concrete structure, a metal structure or a wood structure in which fission is occurring; or comprises an existing fissile concrete structure, a metal structure or a wood structure. A gauge length beam of the strain type micro-gap monitoring device is fixedly arranged on a vertical bisector of a path where fission of the structure to be detected is possible to occur; or the gauge length beam of the strain type micro-gap monitoring device is fixedly arranged at the key detection position of the structure to be detected.
Specific examples of the method for fixedly connecting the strain type micro-gap monitoring device with the structure to be measured include:
the installation of the single-dimensional strain type micro-gap monitoring device (also called a sensitive unit) can be divided into two types, namely a damaged installation and a nondestructive installation. The installation process mainly comprises the following steps:
1) the critical detection locations and the fission likely path are determined.
2) For nondestructive installation, the mounting flange is fixed through the special epoxy adhesive, and the fixing principle is that the gauge length cross beam and the fission path are vertical and centered or the mounting flange is fixed through the special epoxy adhesive to fixedly install the strain type micro gap monitoring device at a key detection position.
3) For destructive installation, the mounting flange is fixed by penetrating a bolt through a mounting hole, and the principle of fixing is that the gauge length cross beam and a path where fission is likely to occur are perpendicular and centered or the mounting flange is fixed by using an epoxy special adhesive to fixedly install the strain type micro gap monitoring device at a key detection position. The critical detection location is a location identified by data estimation or industry experience that is necessary to be monitored and/or monitored.
When the key detection position of the structure to be detected (such as a bridge pier and a bridge) is more than one position, or a plurality of key detection positions needing to be monitored exist, a plurality of micro gap monitoring devices can be utilized to form a micro gap monitoring array, and a plurality of corresponding fission possible occurrence paths or key detection positions configured on the structure to be detected according to different working conditions. The plurality of micro gap monitoring devices are connected in a wired or wireless mode.
After the structure of the monitoring device in fig. 1 is fixed, and the surface of the structure to be measured does not have fission or transverse strain, the resistance value of the strain gauge is kept unchanged, and the output voltage of the bridge is unchanged. When the surface of the structure in the scale distance range is cracked or transversely expanded to cause the two cantilever beams to simultaneously displace outwards, tensile strain resistance values generated by the strain gauges R2 and R3 are increased, compressive strain resistance values generated by the strain gauges R1 and R4 are reduced, and the output voltage of the bridge is increased; when the surface of the structure shrinks in the scale distance range, the two cantilever beams simultaneously displace inwards, the compression strain resistance generated by the strain gauges R2 and R3 is reduced, the tension strain resistance generated by the strain gauges R1 and R4 is increased, and the output voltage of the bridge is reduced.
In addition, when the structure to be measured is impacted or vibrated, the cantilever beam pieces move inwards and outwards at the same time, so that the stress conditions of R1 and R3 are the same as the resistance value change trend, the stress conditions of R2 and R4 are the same as the resistance value change trend, the output of the bridge is kept unchanged, namely the structural design of the sensitive unit can eliminate the interference of the structure to be measured by environmental factors such as impact, vibration and the like, and the coupling measurement is only carried out on the transverse stress of the surface of the structure in a gauge length range. The content of the gauge length related in the embodiment of the invention is the maximum sensitive range of the sensitive unit, and can also be understood as the range of the sensitive unit. A strain gauge micro-gap monitoring device can be understood as a sensitive unit.
Under special conditions, when the structure to be measured (which is equal to the structure to be measured) generates impact or vibration, the cantilever beam pieces displace inwards and outwards at the same time, so that the stress conditions of R1 and R3 are the same as the resistance value change trend, the stress conditions of R2 and R4 are the same as the resistance value change trend, the output of the bridge is kept unchanged, namely the structural design of the sensitive unit can eliminate the interference of the structure to be measured by environmental factors such as impact, vibration and the like, and only the lateral stress of the surface of the structure in a gauge length range is subjected to coupling measurement.
FIG. 2 is a schematic view of a partial structure of a strain type micro gap monitoring device according to an embodiment of the present invention. Fig. 2 shows that a cable sealing plug 6 connected with a cable 7 is further arranged on the gauge length beam 1, the cable 7 at one end of the cable sealing plug is electrically connected with the built-in integrated signal conditioning unit 5, and the cable 7 at the other end of the cable sealing plug is connected with a peripheral data acquisition device or a power supply.
The wheatstone bridge strain gage connection mode in the embodiment of fig. 3 is schematically illustrated. In fig. 3 the bridge excitation voltage is Vin and the bridge output voltage is Vout. Fig. 3 illustrates only one bridge connection. Under the condition that the connection mode of the bridge is determined, the type and the resistance value of the strain gauge can be flexibly configured according to the material of the tested object, the fission width allowable value of the position of the tested point and other factors, the type of the strain gauge depends on the material of the tested object, and the resistance value of the strain gauge is selectable from 100 omega to 1000 omega.
Fig. 4 is a schematic diagram of an internal structure and an operating principle of a signal conditioning unit according to an embodiment of the present invention. Fig. 4 lists circuit function modules of the strain type micro gap monitoring device, including an instrument amplifying circuit, a filter circuit and a voltage stabilizing circuit. The input end of the instrument amplifying circuit is connected with the output end of the strain gauge, and the output end of the instrument amplifying circuit is used for conditioning the small measurement signal from the strain gauge and converting the conditioned small measurement signal into a standard voltage signal for outputting through the filter circuit. The input end of the voltage stabilizing circuit is connected with a power supply, and the output end of the voltage stabilizing circuit is connected with the input end of the strain gauge.
The signal conditioning unit is a built-in integrated signal conditioning unit and is responsible for providing an excitation power supply for a Wheatstone bridge consisting of strain gauges and converting a small signal output by the bridge into a standard voltage signal. Meanwhile, a signal conversion module is embedded according to user requirements, and the final output interface is in a voltage/current/232/485/CAN selectable form. For outdoor mobile portable application, a +12V power supply (common standard battery voltage) is adopted by a strain type micro-gap monitoring device (also called a sensitive unit) to supply power. An external +12V power supply is input and then converted into +5V power through a precise voltage stabilizing circuit to supply power to a Wheatstone bridge formed by a strain gauge, and a small measurement signal output by the bridge is converted into a standard voltage signal after being conditioned through an instrument amplifying circuit and a filter circuit in a signal conditioning unit.
FIG. 5 is a flow chart of a strain type micro gap fission solution method of the invention. Fig. 5 shows a calculation method for strain type micro gap fission, which is based on the strain type micro gap monitoring device and specifically includes the following steps:
s501, estimating a path where fission is likely to occur or determining a key detection position.
And S502, determining the range of the monitoring device, and taking the range as the scale distance L of the sensitive unit.
And S503, determining the thickness h of a single cantilever beam piece, the length l of the single cantilever beam piece and the width b of the single cantilever beam piece in the cantilever beam assembly piece.
S504, the rigidity of the cantilever beam sheet is determined according to the fission or displacement generated in the scale distance of the sensitive unit.
And S505, determining the bending moment of the cantilever beam piece according to the rigidity of the cantilever beam piece.
And S506, determining the interface stress component of the surface of the cantilever beam piece by combining the flexural section modulus of the cantilever beam.
And S507, determining the surface strain of the cantilever beam piece and the strain in the gauge length.
FIG. 6 is a schematic diagram of a strain-type micro-gap fission solution model of the invention. A single-dimensional strain type micro gap sensitive unit calculation model is shown in FIG. 6, the scale distance of a sensitive unit is L, and the thickness h, the length L and the width b of a cantilever beam sheet are shown.
After a path where fission is possible is estimated or a key detection position is determined, the range of the monitoring device is determined and is used as a sensitive unit gauge length L.
And determining the thickness h of a single cantilever beam piece, the length l of the single cantilever beam piece and the width b of the single cantilever beam piece in the cantilever beam assembly piece.
When △ x fission or displacement is generated in the scale distance, the two cantilever beams respectively generate △ x/2 displacement outwards, and the rigidity of the cantilever beams can be expressed as that the rigidity of the cantilever beams is equal to that of the cantilever beamsp is the internal stress of the cantilever beam on the gauge cross beam, E is the internal stress of the cantilever beamModulus of elasticity. Flexural section modulus w of cantilever beam is bh2/6。
Determining the bending moment of the cantilever beam piece according to the rigidity of the cantilever beam piece; the moment of the cantilever beam is
Determining the interface stress component of the surface of the cantilever beam sheet by combining the flexural section modulus of the cantilever beam, wherein the interface stress component of the surface of the cantilever beam sheet is
And determining the surface strain of the cantilever beam sheet and the strain in the gauge length. Surface strain of cantilever beam sheet
Strain in gauge length epsilonL＝△x/L。
Examples are:
if the maximum stretching degree of the strain gauge of the sensitive unit is more than 20000u epsilon, the strain gauge is subjected to strain gauge strainFormula εL△ x/L, assuming the technical requirements of the full-scale displacement △ x to be measured being 0.5mm and the minimum resolution △ x being 0.01mm, the key parameter of the sensing unit to be selected is the thickness h of the cantilever piece being 6mm, the length L of the cantilever piece being 40mm, the width b of the cantilever piece being 28mm, and the scale distance L of the sensing unit being 120 mm.
The related technical index examples of the strain type micro-gap monitoring device and the fission calculating method related to the embodiment of the invention are as follows:
1) the strain type micro-gap monitoring device can monitor the micro-gap within the range of 0.5mm-3mm, and is called as the micro-gap. Namely sensitive fission: can be configured at 0.5mm-3 mm.
2) And (3) sensitive precision: the thickness of the film is 0.01mm-0.05 mm;
3) linearity: is better than or equal to 2 percent;
4) a power supply: the 18V-36V is optional.
The embodiment of the invention realizes the rapid and accurate nondestructive examination of the ongoing fission of the structure to be detected (such as a bridge and a pier) and the nondestructive measurement of the fission of the existing structure on the premise of not damaging the integrity of the structure to be detected. Good technical effect and economic benefit are obtained.
As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or wirelessly coupled. As used herein, the term "and/or" includes all or any element and all combinations of one or more of the associated listed items.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
It will be understood by those within the art that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions. Those skilled in the art will appreciate that the computer program instructions may be implemented by a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, implement the features specified in the block or blocks of the block diagrams and/or flowchart illustrations of the present disclosure.
Those of skill in the art will appreciate that various operations, methods, steps in the processes, acts, or solutions discussed in the present application may be alternated, modified, combined, or deleted. Further, various operations, methods, steps in the flows, which have been discussed in the present application, may be interchanged, modified, rearranged, decomposed, combined, or eliminated. Further, steps, measures, schemes in the various operations, methods, procedures disclosed in the prior art and the present invention can also be alternated, changed, rearranged, decomposed, combined, or deleted.
The foregoing is only a partial embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A strain type micro gap monitoring device is characterized by comprising a gauge length beam, a cantilever beam assembly piece, a strain assembly piece and a built-in integrated signal conditioning unit; the gauge length cross beams are erected on the cantilever beam assemblies which are arranged in pairs, and the cantilever beam assemblies are equal in height, opposite to each other and separated from two end parts of the gauge length cross beams;
the strain gauge is fixedly connected with the lower end part of the cantilever beam gauge, and the strain gauge is configured with a bridge mode of the strain gauge according to different estimated fission width allowable values; the built-in integrated signal conditioning unit is pre-embedded in the gauge length beam and is electrically connected with the strain gauge.
2. The strain gage micro gap monitoring device of claim 1, wherein the bridge pattern of the strain gage elements comprises: full or half bridge or 1/4 bridge.
3. The strain type micro gap monitoring device according to claim 1, further comprising a fixing member for fixedly connecting the strain type micro gap monitoring device with a structure to be measured.
4. The strain type micro gap monitoring device as claimed in claim 3, wherein the strain type micro gap monitoring device is fixedly connected with a structure to be tested, and comprises:
a gauge length beam of the strain type micro-gap monitoring device is fixedly arranged on a vertical bisector of a path where fission of the structure to be detected can occur; or a gauge length beam of the strain type micro-gap monitoring device is fixedly arranged at a key detection position of the structure to be detected;
the structure to be tested comprises a concrete structure, a metal structure or a wood structure which is undergoing fission; or the structure to be tested comprises an existing old fissile concrete structure, a metal structure or a wood structure.
5. The strain type micro gap monitoring device according to claim 1, wherein the built-in integrated signal conditioning unit comprises an instrument amplifying circuit, a filter circuit and a voltage stabilizing circuit, wherein the input end of the instrument amplifying circuit is connected with the output end of the strain gauge, and the output end of the instrument amplifying circuit conditions a small measurement signal from the strain gauge and converts the small measurement signal into a standard voltage signal for output through the filter circuit; the input end of the voltage stabilizing circuit is connected with a power supply, and the output end of the voltage stabilizing circuit is connected with the input end of the strain gauge.
6. The strain gage micro gap monitoring device according to claim 3 or 4, wherein the fixing member comprises a mounting flange, a bolt and/or an epoxy adhesive fixing agent.
7. The strain type micro-gap monitoring device according to claim 4, wherein a plurality of micro-gap monitoring devices form a micro-gap monitoring array, and are configured on the structure to be tested according to different working conditions at a plurality of corresponding fission possible occurrence paths or key detection positions; and the plurality of micro gap monitoring devices are connected in a wired or wireless mode.
8. The strain type micro gap monitoring device as claimed in claim 1, wherein a cable sealing plug connected with a cable is further arranged on the gauge length beam, the cable at one end of the cable sealing plug is electrically connected with the built-in integrated signal conditioning unit, and the cable at the other end of the cable sealing plug is connected with a peripheral data acquisition device or a power supply.
9. A method for resolving strain type micro-gap fission is characterized in that the method is based on a strain type micro-gap monitoring device according to any one of claims 1 to 8, and specifically comprises the following steps:
estimating a path where fission is likely to occur or determining a key detection position;
determining the range of the monitoring device, and taking the range as the scale distance L of the sensitive unit;
determining the thickness h of a single cantilever beam piece, the length l of the single cantilever beam piece and the width b of the single cantilever beam piece in the cantilever beam assembly piece;
determining the rigidity of the cantilever beam sheet according to the fission or displacement generated in the gauge length of the sensitive unit;
determining the bending moment of the cantilever beam piece according to the rigidity of the cantilever beam piece;
determining the interface stress component of the surface of the cantilever beam sheet by combining the flexural section modulus of the cantilever beam;
and determining the surface strain of the cantilever beam sheet and the strain in the gauge length.
10. The strain type micro slit fission solution method according to claim 9, wherein,
the cantilever beam piece has a rigidity of
The moment of the cantilever beam is
Flexural section modulus w of cantilever beam is bh2/6；
The interfacial stress component of the surface of the cantilever beam sheet is
Surface strain of cantilever beam sheet
Strain in gauge length epsilonL＝Δx/L。
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