A fiber grating-based phosphogypsum concrete product strength detection device and method

Abstract

The present invention discloses a device and method for detecting the strength of phosphogypsum concrete products based on fiber gratings. The device includes a pressure shell and an elastomer connected to the pressure shell, and also includes a first fiber grating. The pressure shell includes a diaphragm, a shell and a sealing cover. After the elastomer is pre-stretched, one end is connected to the top of the shell, and the other end is connected to the middle of the diaphragm. The first fiber grating is bonded to the elastomer after the pre-stretch is applied; a top column is also fixedly connected to the sealing cover, and the top of the top column is connected to the middle of the elastomer; the sealing cover is sealed and glued to the shell. The present invention can detect the strength of phosphogypsum concrete products for a long time, and the detection results are accurate and reliable. It can be used to analyze engineering performance and building safety level during the long-term service of the project, and at the same time provide strong technical support for the next stage of engineering application of phosphogypsum.

Description

Technical Field

[0001] The invention belongs to the technical field of phosphogypsum materials, and in particular relates to a phosphogypsum concrete product strength detection device and method based on optical fiber grating. Background Art

[0002] Phosphogypsum has good environmental performance and has been gradually applied to engineering fields such as phosphogypsum concrete road construction. As a substitute or supplementary material for concrete aggregate, phosphogypsum has the defects of low strength and poor weather resistance. Although this defect can be overcome through process paths, it is still unclear whether the strength of phosphogypsum concrete products can meet the engineering design requirements when they reach a certain service life during the long-term service of the construction project. Therefore, the study of the strength life of phosphogypsum concrete products not only has a monitoring effect on engineering construction, but also has a guiding role in the application of phosphogypsum concrete in the next stage. Summary of the invention

[0003] In view of the technical problems existing in the prior art, the present invention provides a device and method for detecting the strength of phosphogypsum concrete products based on fiber gratings. The present invention can detect the strength of phosphogypsum concrete products for a long time, and the detection result is accurate and reliable. It can be used to analyze the project performance and the safety level of the building during the long-term service of the project, and at the same time provide strong technical support for the next stage of engineering application of phosphogypsum.

[0004] According to a first aspect of the present invention, there is provided a phosphogypsum concrete product strength detection device based on fiber grating, which comprises a pressure shell and an elastomer connected to the pressure shell, and also comprises a first fiber grating. The pressure shell comprises a diaphragm, a shell and a sealing cover. After a pre-stretching amount is applied to the elastomer, one end is connected to the top end of the shell, and the other end is connected to the middle part of the diaphragm. After a pre-stretching amount is applied to the first fiber grating, it is bonded to the elastomer; a top column is also fixedly connected to the sealing cover, and the top end of the top column is connected to the middle part of the elastomer; the sealing cover is sealed and glued to the shell.

[0005] Preferably, the top end of the top column is connected to the back side of the first fiber grating bonded to the elastomer.

[0006] Preferably, it also includes a first metal tube and a second metal tube connected to the outer wall of the pressure shell, the first metal tube and the second metal tube are used for leading out the sensing optical fiber, and the first metal tube and the second metal tube are in the same optical path as the first optical fiber grating.

[0007] Preferably, a groove is provided on the first metal tube or the second metal tube, and the second fiber grating is installed in the groove.

[0008] Preferably, the reflectivity of the first fiber grating is lower than 0.05%.

[0009] Preferably, the wavelength interval between the first fiber grating and the second fiber grating is greater than 4 nm.

[0010] A second aspect of the present invention provides a method for testing the strength of phosphogypsum concrete products, comprising:

[0011] Assemble the sensor, apply pre-stretching to the elastic body, connect one end to the top of the housing, and connect the other end to the middle of the diaphragm, apply pre-stretching to the first fiber Bragg grating and bond it to the elastic body, finally seal the housing, connect the transmission optical fiber to the sensor, and encapsulate and protect the end of the optical fiber;

[0012] Install the sensor, determine the sensor detection position, fix the assembled sensor to the predetermined position, and secure it;

[0013] Making phosphogypsum concrete products;

[0014] Unwrap the optical fiber, connect one end to the light source and the other end to the demodulator;

[0015] The light source is turned on to emit a light source signal, and the demodulator is turned on to demodulate the light source signal. The light signal is processed into an evaluation index reflecting the strength of the phosphogypsum concrete product and recorded according to the time axis.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0017] The present invention can detect the strength of phosphogypsum concrete products over a long period of time, and the detection results are accurate and reliable. It can be used to analyze engineering performance and building safety levels during the long-term service of the project, and at the same time provide strong technical support for the next stage of engineering application of phosphogypsum.

[0018] The present invention does not require energy consumption during use, has a low detection cost, can choose to perform real-time detection, and can also use regular detection. The detection method is flexible and can be selected according to the conditions of different projects and buildings, and has strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention.

[0020] In the above drawings: 1, pressure shell; 11, diaphragm; 12, shell; 13, sealing cover; 14, top column; 15, first metal tube; 16, second metal tube; 17, groove; 18, second fiber Bragg grating; 2, elastomer; 3, first fiber Bragg grating. DETAILED DESCRIPTION

[0021] The following specific embodiments are only used to make the disclosed content more thorough and comprehensive. The embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] This embodiment provides a phosphogypsum concrete product strength detection device based on fiber grating, which includes a pressure shell 1 and an elastic body 2 connected in the pressure shell 1, and also includes a first fiber grating 3. To improve its accuracy, the reflectivity of the first fiber grating 3 is preferably lower than 0.05%. The pressure shell 1 includes a diaphragm 11, a shell 12 and a sealing cover 13. After the elastic body 2 is pre-stretched, one end is connected to the top of the shell 12, and the other end is connected to the middle of the diaphragm 11. The first fiber grating 3 is bonded to the elastic body 2 after the pre-stretching amount is applied; a top column 14 is also fixedly connected to the sealing cover 13, and the top of the top column 14 is connected to the middle of the elastic body 2; the sealing cover 13 is sealed and glued to the shell 12. In this embodiment, a top column 14 is added between the diaphragm 11 and the elastic body 2, so that the longitudinal pressure deformation of the diaphragm 11 can be converted into the lateral deformation of the elastic body 2, thereby increasing the strain value of the first fiber grating 3 and improving the sensitivity of the detection device.

[0023] On the basis of the above-mentioned embodiments, the present embodiment is a phosphogypsum concrete product strength detection device based on fiber grating, wherein the top end of the top column 14 is connected to the back side of the first fiber grating 3 bonded to the elastomer 2, which can further improve the detection accuracy. When the diaphragm 11 is deformed, since the top column 14 is connected to the middle part of the elastomer 2 and is located on the back side of the first fiber grating 3, the first fiber grating 3 can be deformed along with the deformation of the elastomer, thereby improving its sensitivity to the optical path.

[0024] In some preferred embodiments, it also includes a first metal tube 15 and a second metal tube 16 connected to the outer wall of the pressure shell 1, the first metal tube 15 and the second metal tube 16 are used for leading out the sensing optical fiber, and the first metal tube 15 and the second metal tube 16 are in the same optical path as the first optical fiber grating 3.

[0025] In a further preferred embodiment, a groove 17 is provided on the first metal tube 15 or the second metal tube 16, and a second fiber Bragg grating 18 is installed in the groove 17. In this embodiment, the second fiber Bragg grating mainly plays a compensation role. Since the fiber Bragg grating can sense at multiple points, the second fiber Bragg grating 18 with a different wavelength from the first fiber Bragg grating 3 is selected as a temperature compensation grating. The metal tube is used to ensure that the second fiber Bragg grating 18 will not be affected by pressure. The first fiber Bragg grating 3 and the second fiber Bragg grating 18 are in the same environment. When the temperature and pressure change at the same time, the second fiber Bragg grating 17 can be used as a temperature compensation grating to ensure the normal use of the pressure sensor.

[0026] In some other embodiments, the wavelength interval between the first fiber grating and the second fiber grating is greater than 4 nm to improve the accuracy of its optical sensing.

[0027] A method for detecting the strength of phosphogypsum concrete products, using a phosphogypsum concrete product strength detection device based on fiber grating in the above embodiment, comprising:

[0028] Assemble the sensor, apply pre-stretching to the elastic body 2, connect one end to the top of the housing 12, and connect the other end to the middle of the diaphragm 11, apply pre-stretching to the first fiber grating 3 and bond it to the elastic body 2, finally seal and glue the housing 12, connect the transmission optical fiber to the sensor, and encapsulate and protect the end of the optical fiber;

[0029] Install the sensor, determine the sensor detection position, fix the assembled sensor to the predetermined position, and secure it;

[0030] Making phosphogypsum concrete products;

[0031] Unwrap the optical fiber, connect one end to the light source and the other end to the demodulator;

[0032] The light source is turned on to emit a light source signal, and the demodulator is turned on to demodulate the light source signal. The light signal is processed into an evaluation index reflecting the strength of the phosphogypsum concrete product and recorded according to the time axis.

[0033] Taking the strength detection of phosphogypsum concrete test block as an example, during implementation, the first fiber grating 3 is connected to the demodulator through the first metal tube 15 of the pressure shell 1. The central wavelength of the first fiber grating 3 is 1420 nm, and the central wavelength of the second fiber grating is 1220 nm. The road gives pressure to the pressure shell, and the pressure is transmitted to the diaphragm 11. The deformation of the diaphragm 11 is transmitted to the elastomer 2 in contact with it. The elastomer 2 is blocked by the top column 14 in the middle, causing the elastomer 2 to bend and deform. At the same time, the first fiber grating 3 fixed on the elastomer 2 is also deformed, thereby converting the deformation of the concrete road into the deformation of the fiber grating, and achieving the purpose of detecting the strength of the phosphogypsum concrete test block.

[0034] When the demodulator receives the signal, the deformation value of the grating can be converted based on the relationship between the deformation of the grating and the wavelength, and then the height change under the pressure can be reversely converted, and then the value of the external pressure F can be derived based on the relationship between the deformation and the external pressure, and then the strength value can be converted based on the relationship between the pressure and the strength of the concrete test block. The specific derivation formula and calculation process are common knowledge of fiber grating pressure sensors, and are not the content of the invention of the present invention, so this part of the content will not be repeated in the description of the present invention. The significance of this embodiment is that the elastic body 2 is connected to the middle part of the diaphragm 11, and the first fiber grating is connected to the middle part of the elastic body 2, and then the top column 14 is used to ensure that the first fiber grating 3 can be accurately deformed after being compressed, so that a wider range of pressure values ​​can be detected, and the sensitivity of the detection device can be improved.

[0035] The embodiments of the present invention are only examples and preferred technical solutions and should not be regarded as limiting the present invention. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for testing the strength of phosphogypsum concrete products, characterized in that: A phosphogypsum concrete product strength detection device based on optical fiber Bragg grating (FBG) is used, comprising a pressure shell (1) and an elastic body (2) connected to the pressure shell (1), and also comprising a first optical fiber Bragg grating (3). The pressure shell (1) comprises a diaphragm (11), a shell (12) and a sealing cover (13). After a pre-stretching amount is applied to the elastic body (2), one end is connected to the top end of the shell (12), and the other end is connected to the middle part of the diaphragm (11). After a pre-stretching amount is applied to the first optical fiber Bragg grating (3), it is bonded to the elastic body (2); a top column (14) is fixedly connected to the sealing cover (13), and the top end of the top column (14) is connected to the middle part of the elastic body (2); the sealing cover (13) is sealed and glued to the shell (12), and the top end of the top column (14) is connected to the back side of the first optical fiber Bragg grating (3) bonded to the elastic body (2); specifically comprising the following steps: Assembling the sensor, applying a pre-stretch to the elastic body (2), connecting one end to the top of the housing (12), and connecting the other end to the middle of the diaphragm (11), applying a pre-stretch to the first fiber grating (3) and bonding it to the elastic body (2), finally sealing and gluing the housing (12), and connecting the transmission optical fiber to the sensor, encapsulating and protecting the end of the optical fiber; Install the sensor, determine the sensor detection position, fix the assembled sensor to the predetermined position, and secure it; Making phosphogypsum concrete products; Unwrap the optical fiber, connect one end to the light source and the other end to the demodulator; The light source is turned on to emit a light source signal, and the demodulator is turned on to demodulate the light source signal. The light signal is processed into an evaluation index reflecting the strength of the phosphogypsum concrete product and recorded according to a time axis.

2. The method for testing the strength of phosphogypsum concrete products according to claim 1, characterized in that: The detection device further comprises a first metal tube (15) and a second metal tube (16) connected to the outer side wall of the pressure shell (1), wherein the first metal tube (15) and the second metal tube (16) are used for leading out the sensing optical fiber, and the first metal tube (15) and the second metal tube (16) are in the same optical path as the first optical fiber grating (3).

3. The method for testing the strength of phosphogypsum concrete products according to claim 2, characterized in that: A groove (17) is provided on the first metal tube (15) or the second metal tube (16) of the detection device, and a second optical fiber grating (18) is installed in the groove (17).

4. The strength testing method for phosphogypsum concrete products according to claim 1, characterized in that: The reflectivity of the first fiber grating is lower than 0.05%.

5. The method for testing the strength of phosphogypsum concrete products according to claim 3, characterized in that: The wavelength interval between the first fiber grating and the second fiber grating is greater than 4 nm.

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