High-sensitivity tension-compression type fiber grating sensor

Abstract

The utility model discloses a high-sensitivity tension-compression type fiber grating sensor, and relates to the technical field of fiber grating sensors, in particular to a high-sensitivity tension-compression type fiber grating sensor, which comprises an armor optical cable, and a grating is carved on the exposed part of the end part of the armor optical cable; the elastic elements are arranged on the outer side wall of the grating in a segmented mode, the hoop parts of the elastic elements make contact with the grating, the stress strip parts of the elastic elements are scattered and fixedly connected with the inner side wall of the shell, the stress sensing range of the grating is expanded, meanwhile, the stress strip parts are made of glass fiber filaments, and the stress sensing sensitivity is improved; after the shell is pressed, stress acts on the grating through one or more stress strip parts, and the wavelength of the grating is changed; the drawing wire is fixedly connected with each stress strip part, after the drawing wire is pulled, the stress acts on the grating through the stress strip parts, and the wavelength of the grating is changed, so that the purpose that the fiber grating sensor senses the stress in a high-sensitivity and tension-compression manner is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of optical fiber grating sensors, in particular to a high-sensitivity tension-compression optical fiber grating sensor. Background Art

[0002] At present, fiber Bragg grating surface mounted sensors are in various forms, and several key issues determine their quality, including the following: First, how to improve the sensitivity of the sensor as much as possible from the structural point of view; second, a practical and effective temperature self-compensation mechanism; third, how to expand the strain range as much as possible; for the first problem, one part is to directly stick the grating on the surface of the elastomer. Due to the limitation of the spatial structure, the elastomer has not been subjected to any structural treatment. A small number of them increase the sensitivity by increasing the gauge length of the sensor; for the third problem, the current advanced technology is metallized fiber Bragg grating, and then the grating is laser spot welded on the surface of the metal elastomer. This technology abandons the adhesive and has a good strain transfer effect, but the process is complicated and the price is relatively expensive. It is not widely used in actual projects. Most non-metallized adhesive sensors are prone to creep because the inherent elastic range of the adhesive itself is smaller than that of the metal surface. In this way, the strain elastic range is small and does not meet the force measurement requirements of the measuring point with large strain; therefore, it is of practical significance to study a highly sensitive, tensile and compressive fiber Bragg grating sensor.

[0003] In the published Chinese patent application, publication number: CN210561624U, patent name: a fiber grating sensor, although, the prior art uses an elastic member to connect the first fixing seat and the second fixing seat, so that the elastic member is located between the first fixing seat and the second fixing seat, and the fiber grating passes through the first fixing seat and the second fixing seat and connects with the elastic member, the force of the deformation of the flexible road surface is transmitted to the elastic member, and the elastic member then transmits the force to the fiber grating, and the fiber grating is used to detect the deformation of the elastic member. However, the prior art uses a spring as an elastic member, and uses the spring to vibrate after being subjected to external force, so as to sense the stress change, and then transmits the stress to the grating through the strain gauge. Since the grating sheet area and thickness are relatively large, the grating sheet reduces the stress during stress transmission, weakens the strength of the direct contact between the grating and the stress, limits the accuracy of the grating sensing stress, and causes the sensitivity of the fiber grating sensor to decrease during measurement.

[0004] In summary, in order to solve the problem of low measurement accuracy and sensitivity of the fiber Bragg grating sensor in the prior art, this case is proposed to solve it. Utility Model Content

[0005] 1. Technical issues to be resolved

[0006] In view of the deficiencies of the prior art, the utility model provides a high-sensitivity tension-compression fiber Bragg grating sensor, which solves the problems raised in the above-mentioned background technology.

[0007] (II) Technical solution

[0008] To achieve the above objectives, the utility model is implemented through the following technical solutions: a high-sensitivity tension-compression fiber grating sensor, including an armored optical cable, a grating is engraved on the exposed end portion of the armored optical cable, and also includes a shell, a pulling assembly, and a plurality of elastic elements. The armored optical cable passes through the shell and is fixedly installed thereon, and the grating is located inside the shell; each of the elastic elements is respectively mounted on the outer side wall of the grating, and each of the elastic elements is fixedly connected to the grating; the elastic element is composed of a hoop portion and three stress bar portions, each of the stress bar portions is evenly distributed on the outer side wall of the hoop portion, and one end of the stress bar portion away from the hoop portion abuts against the inner side wall of the shell; the pulling assembly includes a drawing wire, and the drawing wire is fixedly connected to the stress bar portion of each elastic element in turn.

[0009] Optionally, the shell is cylindrical in shape as a whole, and a first plug and a second plug are fixedly installed at both ends of the shell respectively. The armored optical cable passes through the first plug, and the armored optical cable is fixedly installed with the first plug through a press-fit head.

[0010] Optionally, a fixing cylinder is fixedly installed on the second plug and passes through the second plug, and a pull rod and a spring are slidably arranged in the fixing cylinder, one end of the spring is fixedly connected to one end of the pull rod, and the other end of the spring is fixedly connected to the wire drawing.

[0011] Optionally, a first support member and a second support member are fixedly connected to the inner side wall of the shell and located at both ends of the grating, and the two ends of the grating are fixedly connected to the first support member and the second support member, respectively.

[0012] Optionally, a protective layer is adhered to the outer wall of the grating.

[0013] Optionally, the protective layer is made of graphite film.

[0014] (III) Beneficial effects

[0015] The utility model provides a high-sensitivity tension-compression fiber Bragg grating sensor, which has the following beneficial effects:

[0016] The high-sensitivity tension-compression fiber Bragg grating sensor has the effects of high-sensitivity stress perception and compression-tension stress perception through the coordinated arrangement of multiple elastic elements and wire drawing. The elastic elements are arranged in sections on the outer wall of the grating, the hoop parts of the elastic elements are in contact with the grating, and the stress strips of the elastic elements are dispersed and fixedly connected to the inner wall of the shell, thereby expanding the stress perception range of the grating. At the same time, the stress perception sensitivity is improved by using glass fiber yarns for the stress strips. After the shell is compressed, the stress acts on the grating through one or more stress strips, and the grating wavelength changes. The wire drawing is fixedly connected to each stress strip, and after the wire drawing is subjected to tension, the stress acts on the grating through the stress strip, and the grating wavelength changes, thereby achieving the purpose of making the fiber Bragg grating sensor highly sensitive and capable of tension-compression stress perception. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0018] Figure 1 This is a front view structural diagram of the high-sensitivity tension-compression fiber Bragg grating sensor of the utility model;

[0019] Figure 2 It is a cross-sectional structural schematic diagram of the high-sensitivity tension-compression fiber Bragg grating sensor of the utility model;

[0020] Figure 3 for Figure 2 The enlarged structural diagram at A in the middle;

[0021] Figure 4 for Figure 2 The enlarged structural diagram at B in the middle;

[0022] Figure 5 It is a three-dimensional structural schematic diagram of the elastic element in the high-sensitivity tension-compression fiber grating sensor of the utility model.

[0023] In the figure: 1, shell; 2, press-fit head; 3, armored optical cable; 4, first plug; 5, second plug; 6, fixing tube; 7, first support member; 8, elastic element; 801, hoop portion; 802, stress bar portion; 9, grating; 10, protective layer; 11, wire drawing; 12, pull rod; 13, spring; 14, second support member. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indications or implications.

[0025] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments.

[0026] See also Figures 1 to 5 The utility model provides a technical solution: a high-sensitivity tension-compression fiber Bragg grating sensor, including an armored optical cable 3, a grating 9 is engraved on the exposed end portion of the armored optical cable 3, and the high-sensitivity tension-compression fiber Bragg grating sensor also includes a shell 1, a pulling component, and multiple elastic elements 8. The armored optical cable 3 passes through the shell 1 and is fixedly installed therewith, and the grating 9 is located inside the shell 1.

[0027] Each elastic element 8 is respectively mounted on the outer side wall of the grating 9, and each elastic element 8 is fixedly connected to the grating 9. The elastic element 8 is composed of a hoop portion 801 and three stress strip portions 802. Each stress strip portion 802 is evenly distributed on the outer side wall of the hoop portion 801, and one end of the stress strip portion 802 away from the hoop portion 801 abuts against the inner side wall of the housing 1. The stress strip portion 802 is made of glass fiber.

[0028] Among them, by arranging each elastic element 8 in sections on the outer side wall of the grating 9, the hoop portion 801 of each elastic element 8 contacts the grating 9, and the stress bar portion 802 of each elastic element 8 is fixedly connected to multiple points on the inner side wall of the housing 1 in a dispersed state, the stress sensing range of the grating 9 is expanded, and at the same time, the stress sensing sensitivity is improved by using glass fiber yarn for the stress bar portion 802, and the stress reduction is reduced by using glass fiber yarn for the stress bar portion 802. After the housing 1 is compressed, the stress acts on the grating 9 through one or more stress bar portions 802, and the wavelength of the grating 9 changes, thereby realizing high-sensitivity detection of compressive stress.

[0029] The pulling assembly includes a drawing wire 11 , which is fixedly connected to the stress bar portion 802 of each elastic element 8 in sequence.

[0030] By fixedly connecting the wire drawing 11 to each stress bar portion 802 , the wire drawing 11 exerts stress on the grating 9 through the stress bar portion 802 after being subjected to tension, and the wavelength of the grating 9 changes, thereby achieving high-sensitivity detection of tensile stress.

[0031] Specifically, the shell 1 is cylindrical in shape as a whole, and a first plug 4 and a second plug 5 are fixedly installed at both ends of the shell 1 respectively. The armored optical cable 3 passes through the first plug 4, and the armored optical cable 3 is fixedly installed with the first plug 4 through the pressing head 2.

[0032] The housing 1, the first plug 4 and the second plug 5 together form a fiber optic grating sensor housing, which is used to provide outer protection for the grating 9. The pressing head 2 is used to fix the armored optical cable 3 and the first plug 4 together.

[0033] Specifically, a fixed tube 6 is fixedly installed on the second plug 5 and passes through it. A pull rod 12 and a spring 13 are slidably arranged in the fixed tube 6. One end of the spring 13 is fixedly connected to one end of the pull rod 12, and the other end of the spring 13 is fixedly connected to the wire 11.

[0034] Among them, the fixed cylinder 6, the pull rod 12, and the spring 13 are also part of the pulling assembly. The pulling assembly is used to sense the pulling force of the external object to be detected. The pull rod 12 slides to generate displacement after being subjected to the pulling force. The displacement of the pull rod 12 pulls the spring 13. The elastic force of the spring 13 deviates and exerts stress on the stress bar portion 802 of the elastic element 8 through the wire drawing 11. The stress bar portion 802 exerts stress on the grating 9, thereby changing the wavelength of the grating 9.

[0035] Specifically, the first support member 7 and the second support member 14 are fixedly connected to the inner wall of the housing 1 and at both ends of the grating 9 , and the two ends of the grating 9 are fixedly connected to the first support member 7 and the second support member 14 , respectively.

[0036] The first support member 7 and the second support member 14 are used to support and fix the two ends of the grating 9 so that the grating 9 is in a straight state. The grating 9 passes through the first support member 7 and is fixedly connected to the first support member 7. The wire drawing 11 passes through the second support member 14, and the wire drawing 11 does not directly contact the second support member 14.

[0037] Specifically, a protective layer 10 is adhered on the outer wall of the grating 9. The protective layer 10 is made of graphite film.

[0038] The protective layer 10 is used to prevent the hoop portion 801 of the elastic element 8 from directly contacting the grating 9, so as to prevent the elastic element 8 from damaging the grating 9. The hoop portion 801 is made of a metal sheet.

[0039] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A high-sensitivity tension-compression fiber grating sensor, comprising an armored optical cable (3), wherein a grating (9) is engraved on the exposed end portion of the armored optical cable (3), characterized in that: It also comprises a housing (1), a pulling assembly, and a plurality of elastic elements (8); the armored optical cable (3) passes through the housing (1) and is fixedly mounted thereto; and the grating (9) is located inside the housing (1); Each of the elastic elements (8) is respectively mounted on the outer wall of the grating (9), and each of the elastic elements (8) is fixedly connected to the grating (9); The elastic element (8) is composed of a hoop portion (801) and three stress strip portions (802), each of the stress strip portions (802) being evenly distributed on the outer wall of the hoop portion (801), and one end of the stress strip portion (802) away from the hoop portion (801) abuts against the inner wall of the shell (1); the stress strip portion (802) is made of glass fiber; The pulling assembly comprises a drawing wire (11), and the drawing wire (11) is fixedly connected to the stress bar portion (802) of each elastic element (8) in sequence.

2. The high-sensitivity tension-compression fiber Bragg grating sensor according to claim 1, characterized in that: The shell (1) is cylindrical in shape as a whole, and a first plug (4) and a second plug (5) are fixedly mounted on both ends of the shell (1), respectively; the armored optical cable (3) passes through the first plug (4), and the armored optical cable (3) is fixedly mounted on the first plug (4) via a press-fit head (2).

3. The high-sensitivity tension-compression fiber Bragg grating sensor according to claim 2, characterized in that: The second plug (5) is fixedly mounted with a fixed tube (6) passing through it, and a pull rod (12) and a spring (13) are slidably arranged in the fixed tube (6), one end of the spring (13) is fixedly connected to one end of the pull rod (12), and the other end of the spring (13) is fixedly connected to the wire drawing (11).

4. The high-sensitivity tension-compression fiber Bragg grating sensor according to claim 1, characterized in that: A first support member (7) and a second support member (14) are fixedly connected on the inner side wall of the housing (1) and at both ends of the grating (9), and the two ends of the grating (9) are fixedly connected to the first support member (7) and the second support member (14).

5. The high-sensitivity tension-compression fiber Bragg grating sensor according to claim 1, characterized in that: A protective layer (10) is adhered to the outer wall of the grating (9).

6. The high-sensitivity tension-compression fiber Bragg grating sensor according to claim 5, characterized in that: The protective layer (10) is made of graphite film.

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