CN206095169U - Lightweight fiber grating wide range strainometer suitable for microcrack structure - Google Patents

Abstract

The utility model relates to a lightweight fiber grating wide range strainometer suitable for microcrack structure, it includes: the sheetmetal, the sheetmetal has a plurality ofly and the interval sets up, every set up a plurality of through -holes and its surface on the sheetmetal and seted up first recess and a plurality of through -hole, first sleeve pipe, first sleeve pipe setting is adjacent two between the sheetmetal, a plurality of second sleeve pipes, every every is fixed in in the correspondence of second sleeve pipe in the first recess of sheetmetal, fiber grating, fiber grating sets up just pass in the first recess first sleeve pipe with the second sleeve pipe. Directly draw to the grating, the transducing conversion is carried out to no metal section of jurisdiction, promotes fiber grating test stability, its test strain energy reaches 15000 mu epsilon.

Description

A Portable Fiber Bragg Grating Large Range Strain Gauge Suitable for Micro-cracked Structures

technical field

The utility model relates to a strain gauge, in particular to a portable optical fiber grating large-range strain gauge suitable for micro-crack structures.

Background technique

Since the 1970s, fiber optic sensing technology has attracted widespread attention worldwide and has developed rapidly, among which fiber grating sensing technology has developed the most rapidly. Compared with traditional mechanical and electronic sensors, fiber grating sensors have the following advantages: 1. Small size, light weight, 2. Low transmission loss, high bandwidth, 3. Immunity to electromagnetic interference, 4. Corrosion resistance, 5. Long service life , 6. Multiplexing technology can be used for distributed measurement.

Existing fiber grating strain sensors are packaged with elastic transducer structures, and the commonly used packaging methods mainly include substrate type, tube type, and tube-based clamping type at both ends. This type of process has high requirements on the processing accuracy and material type of the package, which leads to complex and costly packaging of fiber grating strain gauges. In the measured structure that pays more attention to the appearance, the traditional packaged strain gauge is particularly abrupt; moreover, the packaged sensor gauge length and range are small, especially in the strain test of heterogeneous media such as soil and concrete, it is easy to be caused by local The development of micro-cracks leads to the failure of the sensor; secondly, the installation of the fiber grating strain gauge produced by this packaging process is very complicated, usually requires drilling and fixing the mounting base, and the sensor is easily damaged during the process of adjusting the tightness. In the case where the structure does not allow drilling, the sensor can only be fixed by sticking. Due to the design of its base and the high-modulus packaged metal tube, the sensor cannot cooperate with the structure to deform, resulting in a large measurement error .

Aiming at the problems caused by the packaging process of the above fiber grating sensor, the Chinese utility model patent with the application number of 201320029537.1 discloses a new type of fiber grating strain gauge, which mainly encapsulates the fiber grating in the steel strand, without metal segments for energy conversion The transformation improves the stability and reliability of the sensor, reduces the packaging cost, and satisfies the deformation measurement of deep rock and soil. However, it is mainly aimed at the strain test inside the rock and soil. For the strain test on the surface of concrete structures, steel structures, wooden structures, etc., the technical solution of steel strand wrapping is not feasible. Therefore, it is necessary to invent a fiber grating strain gauge that has a large test range, is not affected by micro-cracks, does not affect the appearance of the structure, has low packaging cost, is simple and fast in construction, and is suitable for monitoring surface deformation of concrete structures and steel structures.

Contents of the invention

The purpose of the utility model is to provide a portable optical fiber grating large-range strain gauge suitable for micro-crack structures in order to overcome the deficiencies of the prior art.

In order to achieve the above purpose, the technical solution adopted by the utility model is: a portable fiber grating large-range strain gauge suitable for micro-crack structures, which includes:

A metal sheet, the metal sheet has a plurality and is arranged at intervals, each of the metal sheets is provided with a plurality of through holes and its surface is provided with a first groove and a plurality of through holes;

a first sleeve, the first sleeve is fixed between two adjacent metal sheets;

A plurality of second sleeves, each of the second sleeves is correspondingly fixed in the first groove of each of the metal sheets;

A fiber grating, the fiber grating is arranged in the first groove and passes through the first sleeve and the second sleeve.

Preferably, it further includes a connection piece connecting two adjacent metal pieces, and the first sleeve is fixed in the second groove of the connection piece.

Optimally, the first grooves of the plurality of metal sheets are on the same straight line.

Further, there are two rows of through holes on each metal sheet, and they are arranged on both sides of the first groove.

Preferably, the outermost two of the plurality of metal sheets are respectively provided with outlet terminals extending oppositely.

Preferably, the metal sheet is an ultra-thin copper sheet or a stainless steel sheet.

Due to the application of the above technical solutions, the utility model has the following advantages compared with the prior art: the utility model is suitable for a portable optical fiber grating large-range strain gauge with a micro-crack structure, and directly stretches the grating without metal segments. Energy conversion improves the stability of fiber grating testing; its test strain energy reaches 15000με; it is not affected by micro-cracks and meets the surface strain tests of concrete structures, steel structures, wooden structures, etc., and can be pasted by spot welding and epoxy , The method of nail fixing is fixed on the surface of the structure, no need to punch holes, does not damage the structure of the measured object, easy to install, good coupling between the sensor and the structure, and high test sensitivity; quasi-distributed layout measurement, simple layout, does not affect the structure Appearance, the sensor can be covered by painting and other methods, and integrated with the structure; it takes advantage of the technical advantages of fiber grating sensors and reduces its application threshold, so that fiber grating sensors can be widely used.

Description of drawings

Accompanying drawing 1 is the structural representation of the portable fiber grating large range strain gauge that is applicable to micro-crack structure in embodiment 1;

Accompanying drawing 2 is the structural representation of the portable fiber grating large-range strain gauge that is applicable to micro-crack structure in embodiment 2;

Among them, 1. Metal sheet; 11. First groove; 12. Through hole; 13. Outlet terminal; 14. Connecting sheet; 2. Optical fiber grating; 3. First bushing; 4. Second bushing.

detailed description

The utility model will be further described below in conjunction with the embodiment shown in the accompanying drawings.

Example 1

This embodiment provides a portable fiber grating large-range strain gauge suitable for micro-crack structures, as shown in Figure 1, it mainly includes a metal sheet 1, a fiber grating 2, a first sleeve 3 and a second sleeve 4 .

Among them, there are two metal sheets 1 in a sheet-like structure (ultra-thin copper sheet or stainless steel sheet material), which are arranged at intervals; each metal sheet 1 is provided with a plurality of through holes 12 and its surface is provided with first groove 11; through the through hole 12, the metal sheet 1 can be fixed on the surface of the concrete structure, steel structure, wooden structure, etc. for strain testing by means of spot welding, epoxy sticking, or nail fixing, without drilling or destroying The structure of the object to be measured, the installation is simple, and the coupling with the structure is good, which can strengthen the adhesion strength with the object to be measured; in this embodiment, a plurality of through holes 12 form two rows and are arranged on both sides of the first groove 11 . The first grooves 11 of the two metal sheets 1 are on the same straight line, and are used to accommodate the fiber Bragg grating 2, so that the fiber Bragg grating 2 can be stretched directly, and there is no metal segment for energy conversion, which improves the stability of the fiber Bragg grating test. The quantity of the first casing 3 is usually one more than the quantity of the metal sheet 1; like this when there are two metal sheets 1, the number of the first casing 3 is one; its material can be polyurethane elastic material, and the modulus of elasticity is smaller than that of concrete , steel and other materials, can be deformed cooperatively with the structure, and the length can be selected from several centimeters to tens of centimeters according to needs; it is fixed between two metal sheets 1 by bonding glue at the end, which overcomes the micro cracks in the monitoring Impact. The quantity of the second sleeve pipe 4 is consistent with the quantity of metal sheets 1 so that each metal sheet 1 corresponds to a second sleeve pipe 4, so that the second sleeve pipe 4 can be correspondingly fixed in the first groove 11 of the metal sheet 1, and It is arranged at a distance from the first sleeve 3 and is used for leading out the fiber grating 2 . The fiber grating 2 is arranged in the groove 11, which can be sealed and fixed with epoxy resin, and passes through all the first casing 3 and the second casing 4; it can choose a non-destructive high-strength fiber grating, so that the strain The strain energy of the gauge can reach 15000με, and compared with the measurement range of ±1500με of ordinary fiber grating strain gauge, its stretching range is increased by 10 times.

In this embodiment, the edge of the metal sheet 1 extends outward to form the outlet terminal 13, so that the two outlet terminals 13 of the two metal sheets 1 extend oppositely, so that the fiber grating 2 can pass through the second set of higher strength. The tube 4 is led out and sealed and fixed with epoxy resin at the outlet terminal 13, which solves the problem that the optical fiber at the outlet part is easily broken. The width of each segment of the first groove 11 can be set to be different according to actual needs (such as whether the first sleeve 3 or the second sleeve 4 is fixed).

Example 2

As shown in Figure 2, the portable fiber grating large-range strain gauge suitable for micro-crack structures is basically the same in structure as that in Example 1, except that two adjacent metal sheets 1 are connected to each other through connecting sheets 14. Connection (can be a conventional way such as one-piece molding). A second groove (not marked in the figure) on the same line as the first groove 11 is opened on the connecting piece 14, so that the first sleeve 3 can be fixed in the second groove by glue, which can increase the strain gauge High tensile strength, improving the ease of construction.

The above-mentioned embodiments are only to illustrate the technical concept and characteristics of the present utility model, and its purpose is to enable those familiar with this technology to understand the content of the present utility model and implement it accordingly, and not to limit the protection scope of the present utility model. All equivalent changes or modifications made according to the spirit of the utility model shall fall within the protection scope of the utility model.

Claims (6)

1. A portable fiber grating large-range strain gauge suitable for micro-crack structures, characterized in that it comprises: A metal sheet, the metal sheet has a plurality and is arranged at intervals, each of the metal sheets is provided with a plurality of through holes and its surface is provided with a first groove and a plurality of through holes; a first sleeve, the first sleeve is fixed between two adjacent metal sheets; A plurality of second sleeves, each of the second sleeves is correspondingly fixed in the first groove of each of the metal sheets; A fiber grating, the fiber grating is arranged in the first groove and passes through the first sleeve and the second sleeve. 2. The portable fiber grating large-range strain gauge suitable for micro-crack structures according to claim 1, characterized in that: it also includes a connecting piece connecting two adjacent metal sheets, and the first sleeve It is fixed in the second groove of the connecting piece. 3. The portable fiber grating large-range strain gauge suitable for micro-cracked structures according to claim 1, characterized in that: the first grooves of the plurality of metal sheets are on the same straight line. 4. The portable fiber grating large-range strain gauge suitable for micro-crack structures according to claim 3, characterized in that: there are two rows of through-holes on each of the metal sheets, and they are arranged on the first sides of the groove. 5. The portable fiber grating large-range strain gauge suitable for micro-crack structures according to claim 1, characterized in that: the outermost two of the plurality of metal sheets are respectively provided with outgoing terminals extending oppositely . 6. The portable fiber grating large-range strain gauge suitable for micro-cracked structures according to claim 1, wherein the metal sheet is an ultra-thin copper sheet or stainless steel sheet.