Solid rocket engine interface creep optical fiber monitoring method

Abstract

The invention provides a solid rocket engine interface creep optical fiber monitoring method, a monitoring system comprises a sensing optical fiber, a fiber bragg grating demodulator, a data processing module and a display module, and the monitoring method comprises the steps that one end of the sensing optical fiber is connected to the fiber bragg grating demodulator, and the other end of the sensing optical fiber is arranged in a shape like a Chinese character'hui 'along a solid rocket engine interface; forming a fiber grating sensor array; the method comprises the following steps: measuring interface stress information of a solid rocket engine by using a fiber grating demodulator, and sending monitoring data to a data processing module; the data processing module is used for preprocessing and analyzing the interface stress monitoring data of the solid rocket engine and monitoring the interface creep state of the solid rocket engine; according to the solid rocket engine interface creep monitoring method, the sensing optical fiber is directly implanted into the solid rocket engine interface, the interface creep area and creep speed can be accurately positioned, and the solid rocket engine interface creep monitoring method has the advantages of being high in detection precision, wide in application range and capable of achieving full-life real-time monitoring.

Description

Technical Field

[0001] The invention relates to the field of solid rocket intelligent technology, and in particular to a solid rocket engine interface creep optical fiber monitoring method. Background Art

[0002] During the life cycle of solid rocket engines, long-term storage causes interface creep effects, which seriously affects the reliability and life of the engine structure. Therefore, it is of great significance to monitor the interface creep state of solid rocket engines. For the interface creep effect of solid rocket engines, the most widely used method is to establish an interface cohesion model based on finite element tools and identify the evolution law of creep effect through numerical simulation. However, the interface creep failure mechanism and process of solid rocket engines are not yet fully understood, and there is a lack of effective theoretical explanation for the mechanism of interface performance change. The method based on the interface cohesion model is difficult to obtain the true creep state of the solid rocket engine interface. A monitoring method that can achieve long-term and accurate detection of the interface creep state of solid rocket engines is urgently needed.

[0003] There are also existing technologies that use fiber optic sensing technology to detect rocket engines. For example, Chinese patent document CN 115539253A records a fiber grating array for monitoring the combustion surface retreat of solid rocket engines, CN 115560804A records a solid rocket engine structural integrity monitoring simulation demonstration verification system, and CN117489492A records a solid rocket engine test state health monitoring system, but none of the above technologies involve the study and monitoring of interface creep effects. The difficulty of applying fiber optic sensing technology to interface creep effect monitoring lies in the data information analysis method. Fiber optic sensors collect strain information at discrete points, and interface creep effect is deformation information distributed on the regional surface. How to establish an analysis method for fiber optic strain to interface creep deformation is an urgent problem to be solved. The present invention proposes a method for constructing two-dimensional field information from fiber optic strain point information, and then analyzing and judging the interface creep effect. Summary of the invention

[0004] The present invention provides a solid rocket engine interface creep optical fiber monitoring method, which obtains the solid rocket engine interface stress information by implanting a fiber grating sensor array on the solid rocket engine interface, and combines a stress field reconstruction algorithm to invert the solid rocket engine interface stress distribution state and realize interface creep state monitoring.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: A method for monitoring interface creep of a solid rocket engine using an optical fiber. The monitoring system for monitoring interface creep includes a sensing optical fiber, an optical fiber grating demodulator, a data processing module, and a display module, and includes the following steps: S1, connecting one end of the sensing optical fiber to a fiber Bragg grating demodulator, and folding the other end of the sensing optical fiber back and forth in an "S" shape along the edge of the interface of the solid rocket engine, and arranging a plurality of fiber Bragg grating sensors at intervals on the "S" shaped sensing optical fiber (1) to form a fiber Bragg grating sensor array; S2, using a fiber Bragg grating demodulator to measure the interface stress information of the solid rocket engine, and sending the monitoring data to the data processing module; S3, the data processing module pre-processes and analyzes the solid rocket engine interface stress monitoring data to monitor the solid rocket engine interface creep state; S4. The display module displays the creep state information of the solid rocket engine interface.

[0006] In the above S3, the specific steps of the data processing module preprocessing and analyzing the stress monitoring data are as follows: S3.1. Establish the communication connection between the data processing module and the fiber Bragg grating demodulator to obtain the interface stress monitoring data of the solid rocket engine and set it as the reference stress data, expressed as ;in represents the total number of fiber Bragg grating sensors deployed, and Indicates The coordinates of the fiber grating sensors in the solid rocket motor interface, Indicates Stress monitoring data of FBG sensors; S3.2. Calculate the semivariogram function of any two points on the interface of a solid rocket motor ; S3.3. Calculation of the reference stress distribution on the interface of solid rocket motor ; S3.4. Get the current The solid rocket engine interface stress monitoring data at the moment is obtained through the second and third step calculation process Interface stress distribution of solid rocket motor at time ; S3.5. Calculation of the interface creep state of solid rocket motors ,in represents the creep region, Represents the creep velocity in this area.

[0007] The specific steps of S3.2 above are: First, based on the benchmark stress data, the geometric distance between each measuring point is calculated , then calculate the semivariogram function between each measurement point ,get indivual( ) data pairs, and finally ( ) data pairs are fitted with a polynomial, and the polynomial fitting order is set to 2, and the result is and The functional relationship between ; For any two points on the solid rocket motor interface , , first calculate its geometric distance , and then the semivariogram function of these two points can be obtained according to the fitting curve .

[0008] The specific steps of S3.3 above are: First, calculate the stress data at any position on the solid rocket engine interface, and denote the position to be calculated as , indicating that the stress data at any position is the weighted sum of the values ​​of the nearby fiber Bragg grating sensor measuring points, where Represents the weight coefficient; According to the uniformity of spatial attributes, , , ,Will Bring in , which is simplified to , which is one of the constraints of the weight coefficient; the expected calculation formula of the square of the deviation is , transform the optimal estimate into a conditional extreme value problem and construct the Lagrangian function ,make Minimum, the equation is as follows:

[0009] The semivariogram function of any two points calculated in S3.2 is Substituting the above equation, we can obtain the stress data at any position on the solid rocket engine interface, and finally obtain the benchmark stress distribution of the solid rocket engine interface: .

[0010] In the above S3.5, the creep region and creep rate The calculation formula is: The creep area is calculated as: ; The calculation formula of creep velocity is: .

[0011] In the above S4, the display module displays the identified solid rocket engine interface creep area and creep velocity in the stress distribution cloud map.

[0012] The wavelength range of the above-mentioned fiber grating sensor is 1520nm-1570nm; the central wavelengths of the multiple fiber grating sensors are different and the difference is not less than 1nm.

[0013] The present invention provides a solid rocket engine interface creep optical fiber monitoring method, which has the following beneficial effects: 1. High detection accuracy. The sensing optical fiber is directly implanted into the interface of the solid rocket engine, which can detect the precise interface stress distribution state. At the same time, the fiber grating sensor array can accurately locate the creep area of ​​the solid rocket engine interface and calculate the creep velocity.

[0014] 2. Wide range of applications. The sensing optical fiber has the characteristics of small size, long monitoring distance and passivity. It can be flexibly deployed on various solid rocket engine interfaces without the need for customized monitoring solutions.

[0015] 3. Real-time monitoring throughout the entire life cycle. The sensing optical fiber can collect the interface stress data of the solid rocket engine at any time, and rely on the data processing algorithm to quickly perceive the current creep state of the solid rocket engine interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the layout of the sensing optical fiber of the present invention; Figure 2 It is a schematic diagram of the structure of the monitoring system of the present invention; Figure 3 It is a schematic diagram of the monitoring method flow of the present invention; Figure 4 It is a schematic diagram of the data processing module flow of the present invention.

[0017] Among them: sensing optical fiber 1, fiber Bragg grating demodulator 2, data processing module 3, display module 4, fiber Bragg grating sensor 5, solid rocket engine interface 6. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following content will systematically and completely describe the specific technical solutions of the present invention in combination with the drawings provided according to the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0019] Embodiment 1: A method for monitoring interface creep of a solid rocket engine using an optical fiber. The monitoring system for monitoring interface creep includes a sensing optical fiber 1, an optical fiber grating demodulator 2, a data processing module 3, and a display module 4, and includes the following steps: S1, connect one end of the sensing optical fiber 1 to the fiber Bragg grating demodulator 2, and arrange the other end of the sensing optical fiber 1 in an "S" shape along the edge of the solid rocket engine interface 6, and arrange multiple fiber Bragg grating sensors 5 at intervals on the "S" shaped sensing optical fiber 1, [U1] forming a fiber Bragg grating sensor array; S2, using the fiber grating demodulator 2 to measure the interface stress information of the solid rocket engine, and sending the monitoring data to the data processing module 3; S3, data processing module 3 pre-processes and analyzes the solid rocket engine interface stress monitoring data to monitor the solid rocket engine interface creep state; S4. Display module 4 displays the creep state information of the solid rocket engine interface.

[0020] In the above S3, the specific steps of preprocessing and analyzing the stress monitoring data by the data processing module 3 are as follows: S3.1. Establish the communication connection between the data processing module and the fiber Bragg grating demodulator to obtain the interface stress monitoring data of the solid rocket engine and set it as the reference stress data, expressed as ;in represents the total number of fiber Bragg grating sensors deployed, and Indicates The coordinates of the fiber grating sensors in the solid rocket motor interface, Indicates Stress monitoring data of FBG sensors; S3.2. Calculate the semivariogram function of any two points on the interface of a solid rocket motor ; S3.3. Calculation of the reference stress distribution on the interface of solid rocket motor ; S3.4. Get the current The solid rocket engine interface stress monitoring data at the moment is obtained through the second and third step calculation process Interface stress distribution of solid rocket motor at time ; S3.5. Calculation of the interface creep state of solid rocket motors ,in represents the creep region, Represents the creep velocity in this area.

[0021] The specific steps of S3.2 above are: First, based on the benchmark stress data, the geometric distance between each measuring point is calculated , then calculate the semivariogram function between each measurement point ,get indivual( ) data pairs, and finally ( ) data pairs are fitted with a polynomial, and the polynomial fitting order is set to 2, and the result is and The functional relationship between ; For any two points on the solid rocket motor interface , , first calculate its geometric distance , and then the semivariogram function of these two points can be obtained according to the fitting curve .

[0022] The specific steps of S3.3 above are: First, calculate the stress data at any position on the solid rocket engine interface, and denote the position to be calculated as , indicating that the stress data at any position is the weighted sum of the values ​​of the nearby fiber Bragg grating sensor measuring points, where Represents the weight coefficient; According to the uniformity of spatial attributes, , In order to ensure the accuracy of the calculation results, the reference stress data at any position should satisfy the unbiased property, that is, ,Will Bring in , which is simplified to , which is one of the constraints of the weight coefficient; in order to ensure the accuracy of the calculation results, the reference stress data at any position should also satisfy the optimal estimate, that is, the expectation of the square of the deviation is the smallest; the expected calculation formula of the square of the deviation is , then the optimal estimate can be transformed into a conditional extreme value problem and the Lagrangian function can be constructed ,make Minimum, the equation is as follows:

[0023] The semivariogram function of any two points calculated in S3.2 is Substituting the above equation, we can obtain the stress data at any position on the solid rocket engine interface, and finally obtain the benchmark stress distribution of the solid rocket engine interface: .

[0024] In the above S3.5, the creep region and creep rate The calculation formula is: The creep area is calculated as: ; The calculation formula of creep velocity is: .

[0025] In the above S4, the display module 4 displays the identified solid rocket engine interface creep area and creep velocity in the stress distribution cloud map.

[0026] The wavelength range of the above-mentioned fiber grating sensor 5 is 1520nm-1570nm; the central wavelengths of multiple fiber grating sensors 5 are different and the difference is not less than 1nm. Multiple fiber gratings are used in series to form a fiber grating array. The central wavelengths of multiple gratings are spaced apart from each other, and the spectra do not interfere with each other. By scanning with a light source with a bandwidth of 1520nm-1570nm, all wavelengths of the fiber grating array can be demodulated simultaneously.

[0027] Embodiment 2: like Figures 1 to 4 A solid rocket engine interface creep optical fiber monitoring method is shown, the optical fiber monitoring method includes a sensing optical fiber 1, a fiber grating demodulator 2, a data processing module 3 and a display module 4, and the specific steps of the monitoring method are as follows: Step 1, one end of the sensing optical fiber 1 is connected to the fiber grating demodulator 2, and the other end is arranged in a "U" shape along the solid rocket engine interface 6 to form a fiber grating sensor array; Step 2, using the fiber grating demodulator 2 to measure the stress information of the solid rocket engine interface 6, and sending the monitoring data to the data processing module 3; Step 3, the data processing module 3 pre-processes and analyzes the stress monitoring data of the solid rocket engine interface 6 to monitor the creep state of the solid rocket engine interface 6; Step 4, the display module 4 displays the creep state information of the solid rocket engine interface 6.

[0028] In this embodiment, a plurality of fiber grating sensors 5 are engraved on the sensing optical fiber 1; the wavelength range of the plurality of fiber grating sensors 5 is 1520nm-1570nm; the central wavelengths of the plurality of fiber grating sensors 5 are all different and the difference is not less than 1nm; In this embodiment, the workflow of the data processing module 3 is as follows: The first step is to establish a communication connection between the data processing module 3 and the fiber Bragg grating demodulator 2, obtain the stress monitoring data of the solid rocket engine interface 6, set it as the reference stress data, expressed as .in represents the total number of fiber Bragg grating sensors 5 deployed, and Indicates The coordinates of the fiber grating sensor 5 in the solid rocket motor interface, Indicates Stress monitoring data of 5 fiber Bragg grating sensors.

[0029] The second step is to calculate the semivariogram function of any two points on the solid rocket engine interface 6 First, based on the benchmark stress data, the geometric distance between each measuring point is calculated. , then calculate the semivariogram function between each measurement point ,get indivual( ) data pairs, and finally ( ) data pairs are fitted with a polynomial, and the polynomial fitting order is set to 2, and the result is and The functional relationship between Then for any two points on the solid rocket engine interface 6 , , first calculate its geometric distance , and then the semivariogram function of these two points can be obtained according to the fitting curve .

[0030] Step 3: Calculate the reference stress distribution of the solid rocket motor interface 6 First, calculate the stress data of any position on the solid rocket engine interface 6, and record the position to be calculated as , indicating that the stress data at any position is the weighted sum of the values ​​of 5 nearby fiber grating sensors, where represents the weight coefficient. According to the uniformity of spatial attributes, , In order to ensure the accuracy of the calculation results, the reference stress data at any position should satisfy the unbiased property, that is, ,Will Bring in , which is simplified to , which is one of the constraints of the weight coefficient. In order to ensure the accuracy of the calculation results, the reference stress data at any position should also meet the optimal estimation, that is, the expectation of the square of the deviation is the smallest. The expected calculation formula for the square of the deviation is , then the optimal estimate can be transformed into a conditional extreme value problem and the Lagrangian function can be constructed ,make Minimum, the equation is as follows.

[0031]

[0032] The semivariogram function of any two points calculated in the second step Substituting the above equation, the stress data at any position of the solid rocket engine interface 6 can be obtained, and finally the reference stress distribution of the solid rocket engine interface 6 can be obtained: .

[0033] Step 4: Get the current The stress monitoring data of the solid rocket engine interface 6 at the moment is obtained through the second and third step calculation processes Stress distribution of solid rocket motor interface 6 at time .

[0034] Step 5: Calculate the creep state of the solid rocket motor interface 6 ,in represents the creep region, Represents the creep velocity in this area. The creep area is calculated by The creep velocity calculation formula is: .

[0035] In the sixth step, the display module 4 displays the identified creep area and creep speed of the solid rocket engine interface 6 in the stress distribution cloud map.

[0036] The monitoring method of this embodiment solves the problem of solid rocket engines and has the following advantages: high detection accuracy, the sensing fiber is directly implanted into the interface of the solid rocket engine, and can detect the precise interface stress distribution state. At the same time, the fiber grating sensor array can accurately locate the interface creep area of ​​the solid rocket engine and calculate the creep speed. It has a wide range of applications. The sensing fiber has the characteristics of small size, long monitoring distance, and passiveness. It can be flexibly deployed on various solid rocket engine interfaces without the need for customized monitoring solutions. For full life real-time monitoring, the sensing fiber can collect the interface stress data of the solid rocket engine at any time, and rely on the data processing algorithm to quickly perceive the current interface creep state of the solid rocket engine.

Claims

1. A method for monitoring interface creep of a solid rocket engine using optical fiber, characterized in that: The interface creep optical fiber monitoring system comprises a sensing optical fiber (1), an optical fiber grating demodulator (2), a data processing module (3) and a display module (4), and includes the following steps: S1, connecting one end of the sensing optical fiber (1) to a fiber Bragg grating demodulator (2), and folding the other end back and forth in an "S" shape along the edge of the solid rocket engine interface (6), and arranging a plurality of fiber Bragg grating sensors (5) at intervals on the "S"-shaped sensing optical fiber (1) to form a fiber Bragg grating sensor array; S2, using a fiber grating demodulator (2) to measure the interface stress information of the solid rocket engine, and sending the monitoring data to a data processing module (3); S3, a data processing module (3) pre-processes and analyzes the solid rocket engine interface stress monitoring data to monitor the solid rocket engine interface creep state; S4. The display module (4) displays the creep state information of the solid rocket engine interface.

2. A method for monitoring interface creep of a solid rocket engine according to claim 1, characterized in that: In S3, the specific steps of preprocessing and analyzing the stress monitoring data by the data processing module (3) are as follows: S3.

1. Establish the communication connection between the data processing module and the fiber Bragg grating demodulator to obtain the interface stress monitoring data of the solid rocket engine and set it as the reference stress data, expressed as ;in represents the total number of fiber Bragg grating sensors deployed, and Indicates The coordinates of the fiber grating sensors in the solid rocket motor interface, Indicates Stress monitoring data of FBG sensors; S3.

2. Calculate the semivariogram function of any two points on the interface of a solid rocket motor ; S3.

3. Calculation of the reference stress distribution on the interface of solid rocket motor ; S3.

4. Get the current The solid rocket engine interface stress monitoring data at the moment is obtained through the second and third step calculation process Interface stress distribution of solid rocket motor at time ; S3.

5. Calculation of the interface creep state of solid rocket motors ,in represents the creep region, Represents the creep velocity in this area.

3. A method for monitoring interface creep of a solid rocket engine according to claim 2, characterized in that: The specific steps of S3.2 are: First, based on the benchmark stress data, the geometric distance between each measuring point is calculated , then calculate the semivariogram function between each measurement point ,get indivual( ) data pairs, and finally ( ) data pairs are fitted with a polynomial, and the polynomial fitting order is set to 2, and the result is and The functional relationship between ; For any two points on the solid rocket motor interface , , first calculate its geometric distance , and then the semivariogram function of these two points can be obtained according to the fitting curve .

4. A method for monitoring interface creep of a solid rocket engine according to claim 3, characterized in that: The specific steps of S3.3 are: First, calculate the stress data at any position on the solid rocket engine interface, and denote the position to be calculated as , indicating that the stress data at any position is the weighted sum of the values ​​of the nearby fiber Bragg grating sensor measuring points, where Represents the weight coefficient; According to the uniformity of spatial attributes, , , ,Will Bring in , which is simplified to , which is one of the constraints of the weight coefficient; the expected calculation formula of the square of the deviation is , transform the optimal estimate into a conditional extreme value problem and construct the Lagrangian function ,make Minimum, the equation is as follows: The semivariogram function of any two points calculated in S3.2 is Substituting the above equation, we can obtain the stress data at any position on the solid rocket engine interface, and finally obtain the benchmark stress distribution of the solid rocket engine interface: .

5. A method for monitoring interface creep of a solid rocket engine according to claim 4, characterized in that: In the S3.5, creep region and creep rate The calculation formula is: The creep area is calculated as: ； The calculation formula of creep velocity is: 。 6. A method for monitoring interface creep of a solid rocket engine according to claim 5, characterized in that: In the above-mentioned S4, the display module (4) displays the identified solid rocket engine interface creep area and creep speed in a stress distribution cloud map.

7. The method for monitoring interface creep of a solid rocket engine according to claim 1, characterized in that: The wavelength range of the fiber grating sensor (5) is 1520nm-1570nm; the central wavelengths of the plurality of fiber grating sensors (5) are all different and the difference is not less than 1nm.

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