A temperature and humidity self-sensing bridge main cable intelligent cable fiber sensor design and manufacturing method

Abstract

The application provides a temperature and humidity self-sensing bridge main cable intelligent cable fiber sensor design and manufacturing method. The fiber sensor comprises a fiber grating array, a humidity sensitization sleeve, an adhesive, a spiral sleeve and a stainless steel sleeve; the manufacturing method comprises the following steps: first, arranging the fiber grating array; second, installing the humidity sensing grating sensitization sleeve and the stress isolation sleeve; third, installing the spiral sleeve; fourth, installing the stainless steel sleeve; fifth, positioning and punching the grating; sixth, implanting the intelligent cable into the cable strand; and seventh, connecting the fiber to the anchor head for testing. The fiber sensor provided by the application solves the problem of temperature and humidity self-sensing monitoring of the bridge main cable, has the advantages of high survival rate, long distance, many measuring points, high production efficiency, good durability effect and the like, provides key data information for the maintenance of the bridge main cable, and effectively improves the intelligent level of bridge health monitoring.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of bridge structure health monitoring, and particularly relates to a design and manufacturing method of a temperature and humidity self-sensing bridge main cable intelligent cable optical fiber sensor. BACKGROUND

[0002] The durability of a bridge cable is closely related to the temperature and humidity environment of the internal cable in the long-term service process. Therefore, grasping the temperature and humidity data of the internal cable of the bridge cable is of great value for the structural health monitoring of the cable, especially the durability evaluation. However, the internal temperature and humidity monitoring technology of the bridge cable is difficult, and requires a long measurement distance, a large number of measurement points, a small volume, high durability, and good engineering survival ability. Generally, the sensor is implanted and survives during the manufacturing process of the cable. Domestic and foreign engineering and technical personnel mainly complete the development of bridge cable monitoring technology represented by cable force and strain sensors, but there is no mature scheme for the internal temperature and humidity monitoring of the cable. Therefore, it is urgent to develop a sensor suitable for implanting in the internal cable of the bridge cable for temperature and humidity measurement, and to improve the self-sensing and intelligent level of the bridge cable. SUMMARY

[0003] The application aims to meet the demand of bridge cable structural health monitoring, solve the problem of internal temperature and humidity data measurement of the cable, and proposes a design and manufacturing method of a temperature and humidity self-sensing bridge main cable intelligent cable optical fiber sensor.

[0004] The application is achieved by the following technical scheme. The application proposes a design and manufacturing method of a temperature and humidity self-sensing bridge main cable intelligent cable optical fiber sensor. The optical fiber sensor includes an optical fiber grating array 1, a humidity sensitive sleeve 2, an adhesive 3, a spiral sleeve 4, and a stainless steel sleeve 5. The manufacturing method includes the following steps:

[0005] Firstly, the optical fiber grating array 1 is arranged in pairs of two adjacent gratings, one for humidity measurement and one for temperature measurement.

[0006] Secondly, the humidity sensitive sleeve 2 is sleeved outside the grating for humidity measurement, the gap between the humidity sensitive sleeve 2 and the grating is filled with the adhesive 3, the hole stainless steel sleeve is sleeved outside the humidity sensitive sleeve 2 for stress isolation, and the non-hole stainless steel sleeve is sleeved outside the grating for temperature measurement for stress isolation.

[0007] Thirdly, the optical fiber grating array 1 is coiled on an optical cable machine, the optical fiber is automatically pushed, the stainless steel belt is spirally wound into the spiral sleeve 4, and the spiral sleeve 4 is synchronously sleeved outside the optical fiber grating array 1 to form a spiral sleeve optical cable containing the optical fiber grating array 1.

[0008] Fourthly, the spiral jacketed cable is coiled on the cable machine, and the stainless steel belt is made into a stainless steel jacket 5 in the form of continuous welding and is synchronously sleeved outside the spiral jacket 4 to form the stainless steel jacketed cable;

[0009] Fifthly, the position of the optical fiber grating in the stainless steel jacket 5 is determined by using the heating positioning mode, and a hole is punched at the position of the humidity grating;

[0010] Sixthly, the stainless steel jacketed cable is coiled and installed on the cable production line and is bundled into a main cable strand.

[0011] Seventhly, the stainless steel jacketed cable near the anchor head is led out in advance during the high-temperature anchor filling process of the strand to prevent the high temperature from damaging the optical fiber, and the optical fiber grating array 1 is connected to the testing equipment to collect data.

[0012] Further, the diameter of the optical fiber grating array 1 is not greater than 0.25 mm, the grating pitch of the grating is 3-10 mm, the grating type is a Bragg grating, the grating manufacturing process is lossless writing, and the grating coating layer is damage-free.

[0013] Further, the outer diameter of the humidity sensitive jacket 2 is not greater than 0.6 mm, the inner diameter is not less than 0.26 mm, the length is 20-50 mm, and the material is polyimide.

[0014] Further, the adhesive 3 is made of polyimide solution, the curing method is heating curing, the curing temperature is 140-160℃, and the curing time is 10-30 min.

[0015] Further, the spiral jacket 4 is made of stainless steel, the diameter is 4-5 mm, the wall thickness is 0.1-0.4 mm, the manufacturing process is that the stainless steel belt is wound into a spiral form, and the spiral gap is 0.05-0.2 mm.

[0016] Further, the diameter of the stainless steel jacket 5 is 5-7 mm, the wall thickness is 0.7-1.1 mm, and the manufacturing process is that the stainless steel belt is formed into a circular tube shape in the form of continuous laser welding.

[0017] Further, the arrangement method of the optical fiber grating array 1 in the first step is that firstly, the wavelengths of the gratings are arranged in ascending order, the wavelength range of the gratings is 1510-1610 nm, the wavelength interval between adjacent gratings is not less than 1.5 nm, secondly, the spatial positions of the gratings are distributed in pairs, two gratings form a pair with a spacing of 100-200 mm, the smaller wavelength grating in the pair is determined as a temperature sensing grating, and the larger wavelength grating is determined as a humidity sensing grating, and finally, the wavelength and spatial position information of the grating array are recorded in a registration table.

[0018] Further, the method of filling the gap between the humidity sensing sleeve 2 and the fiber grating array 1 with the adhesive 3 is as follows: first, immerse the humidity sensing sleeve 2 in the adhesive 3 solution; second, use vacuum negative pressure to remove the gas in the solution, so that the adhesive 3 solution fills the gap between the humidity sensing sleeve 2 and the fiber grating array 1; and finally, take out the humidity sensing sleeve 2 and the fiber grating array 1 together and place them in a 140-160°C constant temperature oven for 10-30 minutes for curing.

[0019] Further, the second step of stress isolation is as follows: first, use a stainless steel sleeve with a diameter of 2.5-3.5 mm, a wall thickness of 0.2-0.6 mm, a length of 30-60 mm, and a hole diameter of 0.5-1.2 mm; second, place the stainless steel sleeve outside the humidity sensing sleeve 2 and push the fiber from both ends of the stainless steel sleeve to the center, with the length of the fiber pushed into the stainless steel sleeve being not less than 1% of the length of the stainless steel sleeve; third, inject sealant at both ends of the stainless steel sleeve to bond and fix the sleeve and the fiber, with the bonding length being not less than 3 mm; and finally, after the sealant is cured, the stress isolation of the humidity sensing grating is completed.

[0020] Further, the fifth step positioning and punching method is that, first, the stainless steel sheath armored optical cable is coiled and installed on the pay-off rack, the tail end of the optical cable is connected to the optical fiber demodulator, the wavelength data of all the fiber grating arrays 1 is measured and displayed; second, the head end of the optical cable is connected to the traction device automatic pay-off, the pay-off rate is 5-10 m / min, a hot air gun is arranged at a fixed position, the air temperature is 120-200 DEG C, the passing optical cable is heated, the dynamic change of the grating wavelength data is observed, when the grating wavelength data continuously increases and the change value is greater than 50 pm, the pay-off is paused, the position 0.5 m before and after the hot air gun is determined as the grating coarse positioning area; third, the electric heating wire with a diameter not greater than 1 mm is used for heating, the electric heating wire is in contact with the stainless steel sheath armored optical cable in the grating coarse positioning area, the electric heating wire continuously scans from the starting point to the ending point of the grating coarse positioning area, the position where the wavelength data peak value appears is marked as the grating accurate positioning position, and the corresponding wavelength value is recorded; fourth, the grating array wavelength and spatial position information registration table is consulted, the humidity sensing grating matching the accurate positioning grating wavelength value in the registration table is found, and the accurate positioning of the humidity sensing grating is completed; finally, holes with a diameter of 1-2 mm, a number not less than 3 and a hole depth penetrating the stainless steel sheath wall are punched at the accurate positioning point of the humidity sensing grating.

[0021] The beneficial effects of the present application are:

[0022] 1. Rich sensing parameters, the intelligent cable fiber sensor provided by the present application has both temperature and humidity sensing parameters.

[0023] 2. Good engineering applicability, the intelligent cable fiber sensor provided by the present application has a stainless steel outer protective sleeve, the sleeve diameter is similar to that of the bridge main cable, can not affect the original cable production line, and is implanted into the cable in the original position by the replacement mode, so the engineering applicability is good.

[0024] 3. High degree of automation in manufacturing, the manufacturing method of the intelligent cable fiber sensor provided by the present application reasonably utilizes the automatic manufacturing process, and can adopt the automatic manufacturing mode for the kilometer-level long-distance sensor manufacturing, so the production efficiency is high and the industrial production is easy. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0026] Figure 1 It is a structural schematic diagram of the temperature and humidity self-sensing bridge main cable intelligent cable fiber sensor.

[0027] Figure 2 A temperature and humidity self-sensing bridge main cable intelligent cable fiber sensor design and manufacturing method flowchart is provided in the present application.

[0028] Figure 3 A temperature and humidity self-sensing bridge main cable intelligent cable fiber sensor design and manufacturing method flowchart is provided in the present application.

[0029] In the figure: 1-fiber grating array, 2-humidity sensing sleeve, 3-adhesive, 4-helical sleeve, 5-stainless steel sleeve, 11-humidity sensing grating, 12-temperature sensing grating. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0031] In combination Figures 1-3 , the present application provides a temperature and humidity self-sensing bridge main cable intelligent cable fiber sensor design and manufacturing method, the fiber sensor includes a fiber grating array 1, a humidity sensing sleeve 2, an adhesive 3, a helical sleeve 4, and a stainless steel sleeve 5; the manufacturing method includes:

[0032] Firstly, the fiber grating array 1 is arranged in a way that two adjacent gratings form a pair, one grating is used for humidity measurement, and one grating is used for temperature measurement;

[0033] Secondly, the humidity sensing sleeve 2 is sleeved outside the grating for humidity measurement, the gap between the humidity sensing sleeve 2 and the grating is filled with the adhesive 3, the perforated stainless steel sleeve is sleeved outside the humidity sensing sleeve 2 for stress isolation, and the non-perforated stainless steel sleeve is sleeved outside the grating for temperature measurement for stress isolation;

[0034] Thirdly, the fiber grating array 1 is coiled on the optical cable machine, the stainless steel belt is wound into a helical sleeve 4 in a spiral form while the optical fiber is automatically pushed, and the helical sleeve 4 is synchronously sleeved outside the fiber grating array 1 to form a helical sleeve optical cable containing the fiber grating array 1;

[0035] Fourthly, the helical sleeve optical cable is coiled on the optical cable machine, the stainless steel belt is made into a stainless steel sleeve 5 in a continuous welding form while the helical sleeve optical cable is pushed, and the stainless steel sleeve 5 is synchronously sleeved outside the helical sleeve 4 to form a stainless steel sleeve armored optical cable;

[0036] The fifth step is to determine the position of the grating in the stainless steel sleeve 5 by heating positioning method, and to punch a hole at the humidity grating position;

[0037] The sixth step is to coil the stainless steel sleeve armored optical cable, install it in the cable production line, and bundle it into the main cable strand.

[0038] The seventh step is to lead out the stainless steel sleeve armored optical cable near the anchor head in advance during the high-temperature anchor filling process to prevent high-temperature damage to the optical fiber, connect the fiber grating array 1 with the test equipment to collect data.

[0039] The fiber grating array 1 has a diameter not greater than 0.25mm, a grating pitch of 3mm-10mm, a Bragg grating type, and a non-destructive writing grating manufacturing process.

[0040] The humidity sensitive sleeve 2 has an outer diameter not greater than 0.6mm, an inner diameter not less than 0.26mm, a length of 20mm-50mm, and a polyimide material.

[0041] The adhesive 3 is made of polyimide solution, and the curing method is heating curing, the curing temperature is 140℃-160℃, and the curing time is 10min-30min.

[0042] The spiral sleeve 4 is made of stainless steel, with a diameter of 4mm-5mm and a wall thickness of 0.1-0.4mm, and the manufacturing process is to wind the stainless steel strip into a spiral form.

[0043] The stainless steel sleeve 5 has a diameter of 5-7mm and a wall thickness of 0.7-1.1mm, and the manufacturing process is to form a circular tube shape by continuous laser welding of the stainless steel strip.

[0044] The first step of the fiber grating array 1 is to arrange the wavelength of the grating in order from small to large, with a wavelength range of 1510nm-1610nm and a wavelength interval of not less than 1.5nm between adjacent gratings, and then the spatial position of the grating is distributed in pairs, with a pair of two gratings spaced 100mm-200mm apart, the smaller wavelength grating in the pair is determined as the temperature sensing grating, and the larger wavelength grating is determined as the humidity sensing grating, and finally the wavelength and spatial position information of the grating array is recorded.

[0045] The method of filling the gap between the humidity sensitive sleeve 2 and the fiber grating array 1 with the adhesive 3 is as follows: first, the humidity sensitive sleeve 2 is sleeved outside the humidity sensing grating and immersed in the adhesive 3 solution; second, the gas in the solution is removed by vacuum negative pressure pumping, so that the adhesive 3 solution densely fills the gap between the humidity sensitive sleeve 2 and the fiber grating array 1; finally, the humidity sensitive sleeve 2 and the fiber grating array 1 are taken out together and placed in a 140℃-160℃ constant temperature oven for 10-30min for curing.

[0046] The second step of the grating stress isolation method is as follows: first, a stainless steel sleeve with holes is used, with a diameter of 2.5-3.5mm, a wall thickness of 0.2mm-0.6mm, a length of 30mm-60mm, and a hole diameter of 0.5-1.2mm; second, the stainless steel sleeve with holes is sleeved outside the humidity sensitive sleeve 2, and the optical fiber is pushed from both ends of the stainless steel sleeve with holes to the center of the inside, and the length of the optical fiber pushed into the stainless steel sleeve with holes is not less than 1% of the length of the stainless steel sleeve with holes; third, sealant is injected at both ends of the stainless steel sleeve with holes to bond and fix the sleeve and the optical fiber, and the bonding length is not less than 3mm; after the sealant is cured, the stress isolation of the humidity sensing grating is completed; fourth, a stainless steel sleeve without holes is used, with a diameter of 2.5-3.5mm, a wall thickness of 0.2mm-0.6mm, and a length of 30mm-60mm; fifth, the stainless steel sleeve without holes is sleeved outside the temperature sensing grating, and the optical fiber is pushed from both ends of the stainless steel sleeve to the center of the inside, and the length of the optical fiber pushed into the stainless steel sleeve is not less than 1% of the length of the stainless steel sleeve; sixth, sealant is injected at both ends of the stainless steel sleeve to bond and fix the sleeve and the optical fiber, and the bonding length is not less than 3mm; after the sealant is cured, the stress isolation of the temperature sensing grating is completed.

[0047] The fifth positioning and punching method is: first, coil the stainless steel sheathed optical cable on the pay-off rack, connect the tail end of the optical cable to the optical fiber demodulator, measure and display the wavelength data of all fiber grating arrays 1; second, connect the head end of the optical cable to the traction device automatic pay-off, the pay-off rate is 5-10 m / min, set a hot air gun at a fixed position, the air temperature is 120-200℃, heat the passing optical cable, observe the dynamic change of the grating wavelength data, when the grating wavelength data continuously increases and the change value is greater than 50pm, pause the pay-off, determine the 0.5m range before and after the position of the hot air gun as the coarse positioning area of the grating; third, use an electric heating wire with a diameter not greater than 1mm to contact the stainless steel sheathed optical cable in the coarse positioning area of the grating, continuously scan the electric heating wire from the starting point to the end point of the coarse positioning area, mark the position with the peak wavelength data as the precise positioning position of the grating and record the corresponding wavelength value; fourth, refer to the grating array wavelength and spatial position information registration table to find the humidity sensing grating matching the precisely positioned grating wavelength value, complete the precise positioning of the humidity sensing grating; finally, punch holes at the precise positioning point of the humidity sensing grating, the hole diameter is 1-2mm, the number is not less than 3, and the hole depth must penetrate the stainless steel sheath wall.

[0048] The application provides a temperature and humidity self-sensing bridge main cable intelligent cable optical fiber sensor design and manufacturing method, and belongs to the field of bridge structure health monitoring. The optical fiber sensor comprises a fiber grating array, a humidity sensitization sleeve, an adhesive, a spiral sleeve and a stainless steel sleeve. The manufacturing method comprises the following steps: in the first step, the fiber grating array is arranged in the mode that two gratings form a pair, one grating is used for humidity measurement, and one grating is used for temperature measurement; in the second step, the humidity sensitization sleeve is sleeved outside the grating used for humidity measurement, and the gap between the sleeve and the grating is filled with the adhesive; in the third step, the fiber grating array is coiled on an optical cable machine, the stainless steel belt is sleeved outside the fiber grating in the form of a spiral while the fiber is automatically pushed, and the spiral sleeve optical cable containing the fiber grating array is formed; in the fourth step, the screw sleeve optical cable is coiled on the optical cable machine, the stainless steel belt is sleeved outside the spiral sleeve optical cable in the form of continuous wrapping while the spiral sleeve optical cable is pushed, and the stainless steel sleeve armored optical cable is formed; in the fifth step, the position of the grating in the stainless steel sleeve is determined by using the heating positioning mode, and a hole is punched at the position of the humidity grating; in the sixth step, the stainless steel sleeve armored optical cable is coiled and installed on the cable production line, and is bundled into a main cable strand; and in the seventh step, the stainless steel sleeve optical cable near the anchor head is led out in advance during the high-temperature anchor filling process of the strand, the optical fiber is prevented from being damaged by high temperature, the optical fiber is connected with the test equipment to collect data. The optical fiber sensor provided by the application solves the problem of temperature and humidity self-sensing monitoring of the bridge main cable, has the advantages of survival rate, long distance, many measuring points, high production efficiency, good durability effect and the like, provides key data information for the maintenance of the bridge main cable, and effectively improves the intelligent level of bridge health monitoring.

[0049] Embodiment

[0050] The technical solutions of the application will be further described below in combination with specific implementation cases. As shown in Figure 3 , a temperature and humidity monitoring sensor is installed in a certain bridge main cable, a temperature and humidity self-sensing bridge main cable intelligent cable optical fiber sensor design and manufacturing method is used, a sensor structure is used according to Figure 1 , and the sensor is manufactured according to the steps shown in Figure 2 .

[0051] First, the fiber grating array is arranged in pairs of two adjacent gratings, one for humidity measurement and one for temperature measurement. The diameter of the fiber grating array is 0.25 mm, the grating pitch is 5 mm, the grating type is Bragg grating, the grating manufacturing process is lossless writing, and the grating coating layer is undamaged. The grating wavelengths are arranged in ascending order, with a wavelength range of 1529 nm-1569 nm and a wavelength interval of 2 nm between adjacent gratings. The smaller wavelength grating in the pair is designated as the temperature sensing grating, and the larger wavelength grating is designated as the humidity sensing grating. The two gratings are spaced 200 mm apart. The total length of the fiber grating array is 1500 m, with one pair of temperature and humidity gratings spaced 150 m apart, a total of 10 pairs of gratings. The grating array wavelength and spatial position information are recorded to form a registration table.

[0052] Second, a humidity-sensitive sleeve is wrapped around the humidity measurement grating, and the gap between the sleeve and the grating is filled with adhesive. The humidity-sensitive sleeve is made of polyimide, with an outer diameter of 0.5 mm, an inner diameter of 0.3 mm, and a length of 30 mm. The adhesive is a polyimide solution. The humidity-sensitive sleeve and humidity sensing grating are immersed in the adhesive solution, and a vacuum negative pressure is used to remove the gas in the solution. Then, the assembly is placed in a 150℃ constant temperature oven for 10 minutes to solidify the adhesive. A perforated stainless steel sleeve is wrapped around the humidity-sensitive sleeve to isolate the stress. The perforated stainless steel sleeve has a diameter of 3 mm, a wall thickness of 0.3 mm, a length of 50 mm, and a hole diameter of 0.6 mm with a 4 mm spacing. The fiber is pushed from both ends of the perforated stainless steel sleeve to the center, and the length of the fiber pushed into the perforated stainless steel sleeve is 1 mm. Sealant is injected into both ends of the perforated stainless steel sleeve to bond the sleeve and the fiber, with a bonding length of 3 mm. A non-perforated stainless steel sleeve is wrapped around the temperature measurement grating to isolate the stress. The non-perforated stainless steel sleeve has a diameter of 3 mm, a wall thickness of 0.3 mm, and a length of 50 mm. The fiber is pushed from both ends of the non-perforated stainless steel sleeve to the center, and the length of the fiber pushed into the non-perforated stainless steel sleeve is 1 mm. Sealant is injected into both ends of the non-perforated stainless steel sleeve to bond the sleeve and the fiber, with a bonding length of 3 mm.

[0053] Third, the fiber grating array is coiled on a cable machine, and a stainless steel belt is wound into a spiral sleeve in a spiral form while the fiber is automatically pushed, and the spiral sleeve is wrapped around the fiber grating array to form a spiral sleeve cable containing the fiber grating array. The spiral sleeve has a diameter of 4.5 mm, a wall thickness of 0.2 mm, and a spiral gap of 0.05 mm.

[0054] Fourthly, the screw sleeve cable is coiled on the optical cable machine, while the stainless steel belt is made into a stainless steel sleeve in the form of continuous laser welding and is synchronously sleeved outside the screw sleeve to form a stainless steel sleeve armored optical cable. The stainless steel sleeve has a diameter of 6.5 mm and a wall thickness of 0.8 mm.

[0055] Fifthly, the position of the optical grating inside the stainless steel sleeve is determined by using a heating positioning method, and a hole is punched at the position of the humidity grating.

[0056] Sixthly, the stainless steel sleeve armored optical cable is coiled and installed on a cable production line and is bundled into a main cable strand.

[0057] Seventhly, during the high-temperature anchor filling process of the strand, the stainless steel sleeve armored optical cable near the anchor head is led out in advance to prevent high-temperature damage to the optical fiber, the optical fiber grating array is connected to a test device to collect data.

[0058] The above describes in detail the design and manufacturing method of the temperature and humidity self-sensing bridge main cable intelligent strand optical fiber sensor, and the principles and implementation modes of the present application are described by using specific examples. The above description of the examples is only used to help understand the method of the present application and its core idea. Meanwhile, for those skilled in the art, the specific implementation modes and application ranges will be changed according to the idea of the present application. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A design and manufacturing method for a temperature and humidity self-sensing bridge main cable intelligent fiber optic sensor, characterized in that: The intelligent cable fiber sensor is implanted into the cable by an in-situ replacement method; the fiber sensor comprises a fiber grating array (1), a humidity-sensitizing sleeve (2), an adhesive (3), a spiral sleeve (4) and a stainless steel sleeve (5); the manufacturing method comprises: In the first step, the fiber Bragg grating array (1) is arranged in a manner that two gratings are adjacent to each other to form a pair, wherein one grating is used for humidity measurement and the other grating is used for temperature measurement; The second step is to put a humidity-sensitizing sleeve (2) on the outside of the grating used for humidity measurement, fill the gap between the humidity-sensitizing sleeve (2) and the grating with an adhesive (3), put a stainless steel sleeve with holes on the outside of the humidity-sensitizing sleeve (2) for stress isolation, and put a stainless steel sleeve without holes on the outside of the grating used for temperature measurement for stress isolation; The third step is to coil the fiber grating array (1) on the optical cable machine, and while the optical fiber is automatically pushed, the stainless steel belt is wound into a spiral sleeve (4) in a spiral form, and is synchronously wrapped around the outer side of the fiber grating array (1), forming a spiral sleeve optical cable containing the fiber grating array (1); The fourth step is to coil the spiral sleeve optical cable on the optical cable machine, and while pushing the spiral sleeve optical cable, the stainless steel strip is continuously welded to form a stainless steel sleeve (5), and is simultaneously wrapped around the outside of the spiral sleeve (4) to form a stainless steel sleeve armored optical cable; The fifth step is to use a heating positioning method to determine the grating position in the stainless steel casing (5) and to drill holes at the humidity grating position; Step 6: The stainless steel sheathed armored cable is coiled and installed on the cable production line and bundled into main cable strands; Step 7: During the high-temperature anchoring process of the cable strands, the stainless steel sheathed armored optical cable near the anchor head is led out in advance to prevent the high temperature from damaging the optical fiber, and the fiber grating array (1) is connected to the test equipment to collect data.

2. The method according to claim 1, characterized in that The fiber grating array (1) has a diameter of no more than 0.25 mm, a grating pitch of 3 mm to 10 mm, a Bragg grating type, a grating manufacturing process of non-destructive writing, and a grating coating layer without damage.

3. The method according to claim 1, characterized in that The humidity-sensitizing sleeve (2) has an outer diameter of no more than 0.6 mm, an inner diameter of no less than 0.26 mm, a length of 20 mm to 50 mm, and is made of polyimide.

4. The method according to claim 1, wherein The adhesive (3) is made of polyimide solution and is cured by heating. The curing temperature is 140°C-160°C and the curing time is 10 min-30 min.

5. The method according to claim 1, wherein The spiral sleeve (4) is made of stainless steel, has a diameter of 4 mm to 5 mm, a wall thickness of 0.1 mm to 0.4 mm, and is manufactured by winding a stainless steel strip in a spiral form, with a spiral gap of 0.05 mm to 0.2 mm.

6. The method according to claim 1, characterized in that The stainless steel sleeve (5) has a diameter of 5-7 mm and a wall thickness of 0.7-1.1 mm, and is manufactured by continuously laser welding a stainless steel strip into a round tube shape.

7. The method according to claim 1, characterized in that The arrangement method of the fiber grating array (1) in the first step is that, first, the wavelengths of the gratings are arranged in ascending order, the grating wavelength range is 1510nm-1610nm, and the wavelength interval of adjacent gratings is not less than 1.5nm; second, the spatial positions of the gratings are distributed in pairs, two gratings form a pair, and the interval is 100mm-200mm. The grating with the smaller wavelength in the two gratings in the pair is determined as the temperature sensing grating, and the grating with the larger wavelength is determined as the humidity sensing grating; finally, the grating array wavelength and spatial position information registration table is recorded.

8. The method according to claim 1, characterized in that The method for filling the gap between the humidity-sensitizing sleeve (2) and the fiber grating array (1) with the adhesive (3) in the second step is as follows: first, the humidity-sensitizing sleeve (2) is placed on the outside of the humidity sensing grating and immersed in the adhesive (3) solution; second, the gas in the solution is removed by vacuum negative pressure extraction, so that the adhesive (3) solution densely fills the gap between the humidity-sensitizing sleeve (2) and the fiber grating array (1); finally, the humidity-sensitizing sleeve (2) and the fiber grating array (1) are taken out together and placed in a constant temperature box at 140°C-160°C for curing for 10min-30min.

9. The method according to claim 1, characterized in that The second step of the grating stress isolation method is as follows: first, a stainless steel sleeve with a diameter of 2.5-3.5 mm, a wall thickness of 0.2 mm-0.6 mm, a length of 30 mm-60 mm, a wall opening of 0.5-1.2 mm, and an opening interval of no more than 5 mm is used; second, the stainless steel sleeve with a hole is placed on the outside of the humidity-sensitizing sleeve (2), and the optical fiber is pushed from both ends of the stainless steel sleeve with a hole toward the inner center, and the length of the optical fiber pushed into the stainless steel sleeve with a hole is no less than 1% of the length of the stainless steel sleeve with a hole; Third, inject sealant into both ends of the perforated stainless steel cannula and bond the cannula to the optical fiber, with a bonding length of at least 3 mm. After the sealant solidifies, the stress isolation of the humidity sensing grating is completed. Fourth, use a non-porous stainless steel cannula with a diameter of 2.5-3.5 mm, a wall thickness of 0.2 mm-0.6 mm, and a length of 30 mm-60 mm. Fifth, place the non-porous stainless steel cannula over the outside of the temperature sensing grating and push the optical fiber from both ends of the stainless steel cannula toward the inner center. The length of the optical fiber pushed into the stainless steel cannula must be at least 1% of the length of the stainless steel cannula. Sixth, inject sealant into both ends of the stainless steel sleeve, bond the sleeve to the optical fiber, and the bonding length should be no less than 3mm. After the sealant is cured, the stress isolation of the temperature sensing grating is completed.

10. The method according to claim 7, characterized in that The fifth step of positioning and drilling is as follows: first, the stainless steel sleeve armored optical cable is coiled and installed on a pay-out frame, and the tail end of the optical cable is connected to an optical fiber demodulator to measure and display the wavelength data of all fiber grating arrays (1); Secondly, connect the head end of the optical cable to the traction device for automatic pay-off, with a pay-off rate of 5-10m / min, and set a hot air gun at a fixed position with an air outlet temperature of 120℃-200℃ to heat the passing optical cable and observe the dynamic changes of the grating wavelength data. When the grating wavelength data continues to increase and the change value is greater than 50pm, stop paying out and determine the grating coarse positioning area within 0.5m before and after the position of the hot air gun; thirdly, use electric heating wire for heating, with a diameter of no more than 1mm, and align the electric heating wire with the grating coarse positioning area. The stainless steel sheath is in contact with the armored optical cable, and the heating wire is continuously scanned from the starting point to the end point of the grating coarse positioning area. The position where the wavelength data peak appears is marked as the grating precise positioning position, and the corresponding wavelength value is recorded; fourth, the grating array wavelength and spatial position information registration table is consulted, and the humidity sensing grating that matches the precisely positioned grating wavelength value in the registration table is found to complete the precise positioning of the humidity sensing grating; finally, holes are punched at the precise positioning points of the humidity sensing grating, with a diameter of 1-2 mm and a number of not less than 3. The hole depth must penetrate the stainless steel sheath wall.

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