Three-dimensional Tensile Force Real-time Monitoring Device Based on Optical Fiber Sensing and Its Working Method

Abstract

The present invention discloses a three-dimensional tensile force real-time monitoring device based on fiber optic sensing and its working method. The device includes an optical fiber demodulator and monitoring units arranged in six directions: up, down, left, right, front, and back. The monitoring unit includes a cantilever, a force-receiving plate, a telescopic rod, a pulling rope, a strain sensing optical cable, and a locking member. The optical fiber demodulator is connected to the external strain sensing optical cable of the cantilever of each monitoring unit, and the three-dimensional tensile force is monitored in real time through the strain distribution of each strain sensing optical cable. The structure of the present invention is simple and easy to install, can perform real-time monitoring of three-dimensional tensile force, and avoids external interference.

Description

Technical Field

[0001] The present invention relates to optical fiber sensing monitoring, and particularly to a three-dimensional tensile force real-time monitoring device based on optical fiber sensing and its working method. Background Art

[0002] The sensitivity of the deformation monitoring device based on spring tension is low. Monitoring information can only be obtained when the deformation is significant, and it is difficult to accurately characterize the evolution characteristics during the deformation process. Optical fibers are very sensitive to changes in external environments such as temperature, strain, and vibration. Although the problem of low sensitivity is overcome and it can be widely used in the monitoring field, in order to ensure its smooth completion of the monitoring work, its structure is generally complex and cumbersome. If three-dimensional deformation needs to be monitored, the complexity increases exponentially, and it is also relatively vulnerable to external interference. Summary of the Invention

[0003] The purpose of the present invention is to provide a three-dimensional tensile force real-time monitoring device based on optical fiber sensing and its working method. The structure of the present invention is simple and easy to install, can perform three-dimensional tensile force real-time monitoring, and avoids external interference.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A three-dimensional tensile force real-time monitoring device based on optical fiber sensing includes an optical fiber demodulator and monitoring units arranged in six directions of up, down, left, right, front, and back; the monitoring unit includes a cantilever, a force-bearing plate, a telescopic rod, a pulling rope, a strain sensing optical cable, and a locking member. The inside of the cantilever is hollow with one end closed and the other end open. The force-bearing plate is located at the open end of the cantilever. The telescopic rod is located inside the cantilever and parallel to the cantilever. The telescopic rod adopts a telescopic structure with both ends fixedly connected to the inner side surface of the force-bearing plate and the inner end surface of the cantilever respectively. The pulling rope passes through the cantilever with its inner end connected to the telescopic rod and its outer end being the operating end. When the operating end of the pulling rope is pulled, it can drive the telescopic rod to contract so that the force-bearing plate abuts against and closes the open end of the cantilever. The strain sensing optical cable passes through the cantilever and is divided into two parts inside and outside the cantilever. The locking members are distributed on the inner side surface of the force-bearing plate, the inner end surface of the cantilever, and the outer wall of the cantilever. The locking members on the inner side surface of the force-bearing plate and the inner end surface of the cantilever are used to lock two points of the strain sensing optical cable inside the cantilever to form a pre-tensioned section parallel to the cantilever. The locking member on the outer wall of the cantilever is used to lock the pulling rope after it is pulled in place. An operating opening that can be opened and closed is provided on the cantilever. When the operating opening is opened, the locking members inside the cantilever can be operated; the optical fiber demodulator is connected to the strain sensing optical cable outside the cantilever of each monitoring unit, and the three-dimensional tensile force is monitored in real time through the strain distribution of each strain sensing optical cable.

[0006] Preferably, the telescopic rod is composed of two sections, one section is a cylinder and the other section is a rod. The cylinder and the rod are sleeved together in a sliding fit.

[0007] Further, the inner end face of the cylinder body is fixedly connected to the cantilever, the inner side face of the force-bearing plate is fixedly connected to the rod body, a pulley is arranged inside the cylinder body, one end of the pulling rope is located inside the cylinder body and is connected to the rod body, and the other end bypasses the pulley and first extends out of the side part of the cylinder body and then extends out of the side part of the cantilever.

[0008] Further, lubricating oil is provided between the cylinder body and the rod body.

[0009] Preferably, the locking member includes a stud, a pressing block and a threaded cap. The stud is fixed, the pressing block is sleeved on the smooth rod section of the stud, and the threaded cap is in threaded fit with the threaded section of the stud and is provided with a handle for tightening. When the threaded cap is tightened, the pressing block can be driven to press tightly.

[0010] Preferably, the cantilevers of each monitoring unit converge at a center and are installed together.

[0011] Preferably, the optical fiber demodulator adopts an OFDR optical fiber demodulator.

[0012] Preferably, the operation port is opened and closed through a cover plate or a hatch.

[0013] The working method of the above three-dimensional tensile force real-time monitoring device based on optical fiber sensing includes the steps:

[0014] S1. First, pull the operation end of the pulling rope to drive the telescopic rod to contract so that the force-bearing plate abuts against and closes the open end of the cantilever, keep the pulling rope in a taut state, and use the locking member on the outer wall of the cantilever to lock the pulling rope after it is pulled in place. Then open the operation port, operate the locking member inside the cantilever, first lock a point of the strain sensing optical cable inside the cantilever, and after applying a certain prestress, lock another point of the strain sensing optical cable inside the cantilever. That is, use the locking members on the inner side face of the force-bearing plate and the inner end face of the cantilever to lock two points of the strain sensing optical cable inside the cantilever to form a pre-tensioned section parallel to the cantilever. Then close the operation port to ensure that the inside of the cantilever is closed;

[0015] S2. Place the device in the monitored environment or make the force-bearing plate closely adhere to the object to be monitored, fix the device, and ensure that the device can be in a stable state during the monitoring process without displacement or tilt;

[0016] S3. Release the locking of the pulling rope by the locking member on the outer wall of the cantilever so that the pulling rope and the telescopic rod can move freely. Connect the outer strain sensing optical cables of the cantilevers of each monitoring unit to the optical fiber demodulator and read the initial strain value;

[0017] S4. During the monitoring process, the optical fiber demodulator continuously obtains the strain information of each strain sensing optical cable and monitors the three-dimensional tensile force in real time through the strain distribution of each strain sensing optical cable. By observing the change in the extension amount of the pulling rope, the change in the tensile displacement amount of the corresponding force-bearing plate can be directly known.

[0018] The beneficial effects of the present invention are:

[0019] The device arranges monitoring units in six directions in three-dimensional space, and uses a fiber optic demodulator to continuously obtain the strain information of the strain sensing optical cable in each monitoring unit. It can perform real-time three-dimensional tension monitoring of the monitoring target with high sensitivity. In the device, the cantilever can provide a closed environment for the pre-stretching section of the strain sensing optical cable, avoiding the interference of the external environment on the pre-stretching section of the strain sensing optical cable. The stress plate can withstand the migration and deformation characteristics of gas, liquid and solid and transmit them to the pre-stretching section of the strain sensing optical cable. The telescopic rod can make the stress plate displace when subjected to tension. The pull rope can not only drive the stress plate to resist and close the open end of the cantilever during installation, but also intuitively display the change in the tensile displacement of the corresponding stress plate during the monitoring process. Therefore, the entire device has a simple structure and is easy to install. It can perform real-time three-dimensional tension monitoring and avoid external interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 Schematic diagram of a three-dimensional tension real-time monitoring device based on optical fiber sensing in an embodiment of the present invention.

[0022] Figure 2 It is a schematic longitudinal section diagram of a monitoring unit in an embodiment of the present invention.

[0023] Figure 3 Schematic diagram of a cross section of a monitoring unit in an embodiment of the present invention.

[0024] In the figure: 1-stress plate; 2-cantilever; 3-strain sensing optical cable; 4-optical fiber demodulator; 5-locking piece; 501-stud; 502-pressure block; 503-threaded cover; 6-pull rope; 7-lubricating oil; 8-telescopic rod; 9-pulley; 10-inner end surface. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0026] Accordingly, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application.

[0027] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0028] In the description of the present application, it should also be noted that unless otherwise clearly defined and limited, the terms "arranged", "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0029] The features and performance of the present application will be further described in detail below in conjunction with embodiments.

[0030] Embodiment 1

[0031] This embodiment discloses a three-dimensional tensile force real-time monitoring device based on fiber optic sensing, including a monitoring unit and a fiber optic demodulator 4, as shown in Figure 1 ; the monitoring unit is arranged in six directions: up, down, left, right, front, and back, as shown in Figure 1 ; the fiber optic demodulator 4 is connected to the strain sensing optical cables 3 of each monitoring unit, and the three-dimensional tensile force is monitored in real time through the strain distribution of each strain sensing optical cable 3, as shown in Figure 1 and Figure 2 . As shown in Figures 1 to 3 , the monitoring unit includes a cantilever 2, a force-bearing plate 1, a telescopic rod 8, a pull rope 6, a strain sensing optical cable 3, and a locking member 5, where: the inside of the cantilever 2 is hollow and one end is closed and the other end is open, as shown in Figure 2 ; the force-bearing plate 1 is located at the open end of the cantilever 2, as shown in Figure 2 ; the telescopic rod 8 is located inside the cantilever 2 and is parallel to the cantilever 2. The telescopic rod 8 adopts a telescopic structure and its two ends are respectively fixedly connected to the inner side surface of the force-bearing plate 1 and the inner end surface 10 of the cantilever 2, as shown in Figure 2 and Figure 3 ; the pull rope 6 passes through the cantilever 2 and its inner end is connected to the telescopic rod 8, and the outer end is an operating end. When the operating end of the pull rope 6 is pulled, the telescopic rod 8 can be driven to contract so that the force-bearing plate 1 abuts against and closes the open end of the cantilever 2, as shown in Figure 2 ; the strain sensing optical cable 3 passes through the cantilever 2 and is divided into two parts inside and outside the cantilever 2, as shown in Figure 2; The locking members 5 are distributed on the inner side surface of the force-bearing plate 1, the inner end surface 10 of the cantilever 2, and the outer wall of the cantilever 2. The locking members 5 on the inner side surface of the force-bearing plate 1 and the inner end surface 10 of the cantilever 2 are used to lock two points of the strain sensing optical cable 3 inside the cantilever 2 to form a pre-tensioned section parallel to the cantilever 2, and the locking members 5 on the outer wall of the cantilever 2 are used to lock the draw rope 6 after it is pulled in place. See Figure 2 ; An operable opening that can be opened and closed is provided on the cantilever 2. When the operable opening is opened, the locking members 5 inside the cantilever 2 can be operated.

[0032] Regarding the installation of each monitoring unit, in this embodiment, preferably: as Figure 1 shown, the cantilevers 2 of each monitoring unit converge at a center and are installed together. This setting facilitates the overall placement in the monitored environment or makes the force-bearing plate 1 closely adhere to the object to be monitored.

[0033] Regarding the installation structure of the telescopic rod 8 and the draw rope 6, in this embodiment, preferably: as Figure 2 shown, the telescopic rod 8 is composed of two sections, one is a cylinder and the other is a rod. The cylinder and the rod are sleeved together in a sliding fit. The telescopic rod 8 adopts a two-section structure instead of a multi-section structure to ensure stability and avoid excessive deflection; as Figure 2 shown, the cylinder is fixedly connected to the inner end surface 10 of the cantilever 2, the rod is fixedly connected to the inner side surface of the force-bearing plate 1. A pulley 9 is provided inside the cylinder. One end of the draw rope 6 is located inside the cylinder and is connected to the rod, and the other end bypasses the pulley 9 and then extends out of the side of the cylinder and then out of the side of the cantilever 2. The pulley 9 has a smooth steering function to prevent the draw rope 6 from jamming; as Figure 2 shown, a lubricating oil 7 is provided between the cylinder and the rod to ensure smooth telescoping.

[0034] Regarding the structure of the locking member 5, in this embodiment, preferably: as Figure 2 shown, the locking member 5 includes a stud 501, a pressure block 502, and a threaded cover 503. The stud 501 is fixed, the pressure block 502 is sleeved on the smooth rod section of the stud 501, and the threaded cover 503 is in threaded fit with the threaded section of the stud 501 and is provided with a handle for tightening. When the threaded cover 503 is tightened, it can drive the pressure block 502 to press tightly. The structure of this locking member 5 is relatively simple. Locking is achieved by pressing with the pressure block 502. Only by loosening the threaded cover 503 can it be unlocked, and the operation is simple.

[0035] In this embodiment, the optical fiber demodulator 4 preferably adopts an OFDR optical fiber demodulator 4, which has the advantages of high precision and high resolution.

[0036] In this embodiment, the operable opening can be opened and closed through structures such as a cover plate and a hatch door, which are relatively conventional structures, so they are not shown in the figure.

[0037] Embodiment Two

[0038] This embodiment discloses the working method of the above-mentioned three-dimensional tensile force real-time monitoring device based on optical fiber sensing:

[0039] S1. First, pull the operating end of the pull rope 6 to drive the telescopic rod 8 to contract, so that the force-bearing plate 1 abuts against and closes the open end of the cantilever 2, keep the pull rope 6 in a taut state, and use the locking member 5 on the outer wall of the cantilever 2 to lock the pull rope 6 after being pulled in place. Then, open the operation port, operate the locking member 5 inside the cantilever 2, first lock a point of the strain sensing optical cable 3 inside the cantilever 2, and after applying a certain prestress, lock another point of the strain sensing optical cable 3 inside the cantilever 2, that is, use the locking members 5 on the inner side surface of the force-bearing plate 1 and the inner end surface 10 of the cantilever 2 to lock two points of the strain sensing optical cable 3 inside the cantilever 2 to form a pre-tensioned section parallel to the cantilever 2. Then, close the operation port to ensure that the inside of the cantilever 2 is closed; this step ensures that the pre-tensioned section of the strain sensing optical cable 3 is in a closed environment, and ensures that the force-bearing plate 1 can withstand the migration and deformation characteristics of gas, liquid and solid and conduct them to the pre-tensioned section of the strain sensing optical cable 3.

[0040] S2. Place the device in the monitored environment or make the force-bearing plate 1 closely adhere to the object to be monitored, fix the device, and ensure that the device can be in a stable state during the monitoring process without displacement or tilt; this step ensures that the monitoring directions of the strain sensing optical cables 3 in each monitoring unit do not deviate.

[0041] S3. Release the locking of the pull rope 6 by the locking member 5 on the outer wall of the cantilever 2, so that the pull rope 6 and the telescopic rod 8 can move freely, connect the strain sensing optical cable 3 outside the cantilever 2 of each monitoring unit to the optical fiber demodulator 4, and read the initial strain value; this step ensures that the device can work normally and record.

[0042] S4. During the monitoring process, the optical fiber demodulator 4 continuously obtains the strain information of each strain sensing optical cable 3 and real-time monitors the three-dimensional tensile force through the strain distribution of each strain sensing optical cable 3. By observing the change in the extension amount of the pull rope 6, the change in the tensile displacement amount of the corresponding force-bearing plate 1 can be directly known; in this step, the optical fiber demodulator 4 can monitor microscopic deformation, and the pull rope 6 can display macroscopic deformation.

[0043] This device is equipped with monitoring units arranged in six directions in three-dimensional space. By continuously obtaining the strain information of the strain sensing optical cable 3 in each monitoring unit using the optical fiber demodulator 4, it can perform real-time three-dimensional tensile monitoring on the monitoring target with high sensitivity. In this device, the cantilever 2 can provide a closed environment for the pre-tensioned section of the strain sensing optical cable 3, avoiding interference from the external environment to the pre-tensioned section of the strain sensing optical cable 3. The force-bearing plate 1 can withstand the migration and deformation characteristics of gases, liquids, and solids and conduct them to the pre-tensioned section of the strain sensing optical cable 3. The telescopic rod 8 can cause the force-bearing plate 1 to displace when subjected to tension. The pull rope 6 can not only drive the force-bearing plate 1 to abut against and close the open end of the cantilever 2 during installation but also intuitively display the change in the tensile displacement amount of the corresponding force-bearing plate 1 during the monitoring process. Therefore, the entire device has a simple structure, is easy to install, can perform real-time three-dimensional tensile monitoring, and avoids external interference.

[0044] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of this application that is claimed, but merely represents selected embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without making creative efforts fall within the scope of protection of this application.

Claims

1. A three-dimensional tension real-time monitoring device based on optical fiber sensing, characterized in that: It includes an optical fiber demodulator and monitoring units arranged in six directions: up, down, left, right, front and back; the monitoring unit includes a cantilever, a force plate, a telescopic rod, a pull rope, a strain sensing optical cable and a locking piece. The cantilever is hollow inside and one end is closed and the other end is open. The force plate is located at the open end of the cantilever, the telescopic rod is located inside the cantilever and is parallel to the cantilever. The telescopic rod adopts a telescopic structure and the two ends are respectively fixedly connected to the inner side of the force plate and the inner end surface of the cantilever. The pull rope passes through the cantilever and the inner end is connected to the telescopic rod, and the outer end is the operating end. When the operating end of the pull rope is pulled, the telescopic rod can be driven to contract so that the force plate resists and closes the open end of the cantilever. The strain sensing optical cable passes through the cantilever and is divided into two parts, inside and outside the cantilever. The locking parts are distributed on the inner side surface of the force-bearing plate, the inner end surface of the cantilever and the outer wall of the cantilever. The locking parts on the inner side surface of the force-bearing plate and the inner end surface of the cantilever are used to lock the strain sensing optical cable inside the cantilever at two points to form a pre-stretched section parallel to the cantilever. The locking parts on the outer wall of the cantilever are used to lock the pull rope after it is pulled into place. An operating port that can be opened and closed is provided on the cantilever. When the operating port is opened, the locking parts inside the cantilever can be operated; the optical fiber demodulator is connected to the strain sensing optical cable outside the cantilever of each monitoring unit, and the three-dimensional tension is monitored in real time through the strain distribution of each strain sensing optical cable.

2. The three-dimensional tension real-time monitoring device based on optical fiber sensing according to claim 1, characterized in that: The telescopic rod is composed of two sections, one section is a cylinder body and the other section is a rod body, and the cylinder body and the rod body are sleeved together in a sliding manner.

3. The three-dimensional tension real-time monitoring device based on optical fiber sensing according to claim 2, characterized in that: The cylinder is fixedly connected to the inner end surface of the cantilever, and the rod is fixedly connected to the inner side surface of the force plate. A pulley is arranged in the cylinder. One end of the pull rope is located in the cylinder and connected to the rod, and the other end passes around the pulley and extends out of the side of the cylinder first and then the side of the cantilever.

4. The three-dimensional tension real-time monitoring device based on optical fiber sensing according to claim 2, characterized in that: Lubricating oil is provided between the cylinder body and the rod body.

5. The three-dimensional tension real-time monitoring device based on optical fiber sensing according to claim 1, characterized in that: The locking piece includes a stud, a pressure block and a threaded cover. The stud is fixed, the pressure block is hollowly sleeved on the bare rod section of the stud, the threaded cover is threadedly fitted on the threaded section of the stud and has a handle for tightening. When the threaded cover is tightened, the pressure block can be driven to tighten.

6. The three-dimensional tension real-time monitoring device based on optical fiber sensing according to claim 1, characterized in that: The cantilevers of each monitoring unit are gathered in a center and installed together.

7. The three-dimensional tension real-time monitoring device based on optical fiber sensing according to claim 1, characterized in that: The optical fiber interrogator adopts OFDR optical fiber interrogator.

8. The three-dimensional tension real-time monitoring device based on optical fiber sensing according to claim 1, characterized in that: The operating opening is opened and closed by a cover or a hatch.

9. A working method of the three-dimensional tension real-time monitoring device based on optical fiber sensing according to any one of claims 1 to 8, characterized in that: Includes steps: S1. First pull the operating end of the pull rope to drive the telescopic rod to contract so that the force plate contacts and closes the open end of the cantilever, keep the pull rope taut and use the locking piece on the outer wall of the cantilever to lock the pull rope after it is pulled into place, then open the operating port, operate the locking piece in the cantilever, first lock one point of the strain sensing optical cable in the cantilever, and lock another point of the strain sensing optical cable in the cantilever after applying a certain prestress, that is, use the locking pieces on the inner side surface of the force plate and the inner end surface of the cantilever to lock the two points of the strain sensing optical cable in the cantilever to form a pre-stretched section parallel to the cantilever, and then close the operating port to ensure that the inside of the cantilever is closed; S2. Place the device in the monitored environment or make the force-bearing plate close to the monitored object, and fix the device to ensure that the device is in a stable state during the monitoring process without displacement or tilt; S3, release the lock on the pull rope by the locking piece on the outer wall of the cantilever, so that the pull rope and the telescopic rod can move freely, connect the cantilever external strain sensing optical cable of each monitoring unit to the optical fiber demodulator, and read the initial strain value; S4. During the monitoring process, the optical fiber demodulator continuously obtains the strain information of each strain sensing optical cable and monitors the three-dimensional tension in real time through the strain distribution of each strain sensing optical cable. By observing the change in the extension amount of the pull rope, the change in the tensile displacement of the corresponding force-bearing plate can be intuitively known.

Images