Device and method for monitoring total longitudinal bending moment of ship body, terminal and medium

Abstract

The invention relates to a hull total longitudinal bending moment monitoring device and method, a terminal and a medium, belongs to the field of structural health monitoring, and aims to solve the problems of high cost and low precision of existing bending moment monitoring. The long baseline sensor is fixedly installed on a to-be-monitored point of a hull bottom structure, the long baseline sensor is in data connection with the data receiving processor, and the data receiving processor and the terminal are in data connection with the medium. The device can accurately simulate the working condition, improves the measurement precision and stability of the sensor, is simple and convenient to operate, improves the working efficiency, is flexible in structure, and has multiple driving modes. According to the method, long-distance bending moment recognition is converted into short-distance displacement recognition, long-baseline deck bending moment is converted into short-baseline displacement measurement through a high-rigidity iron pipe and a universal joint, the bending moment can be recognized based on local displacement information by constructing a transfer matrix, and compared with a traditional technology, the method is simple and efficient in algorithm, high in measurement precision, high in interference resistance, convenient to install and high in practicability. The cost is greatly reduced; and the maintenance is simple.

Description

Technical Field

[0001] The invention relates to a device, a method, a terminal and a medium for monitoring the total longitudinal bending moment of a hull, and belongs to the field of structural health monitoring. Background Art

[0002] Hull bending moment refers to the mechanical response when the hull bends in the longitudinal direction due to uneven loads or external forces (such as wave pressure and gravity). The background technology of hull bending moment monitoring originates from the development of engineering mechanics, sensor technology and structural health monitoring (SHM). With the increase in hull size and complexity, it is crucial to understand the stress conditions of the hull under waves, cargo loads and environmental stresses, especially in the design and operation of modern large hulls (such as tankers, container ships and warships). This demand has led to the birth and development of hull bending moment monitoring technology.

[0003] The earliest bending moment monitoring used mechanical strain gauges to record the stress or deformation of the structure through mechanical pointers. Strain measurement technology, optical fiber technology, and vibration and acceleration measurement technology have now been developed. Strain measurement technology has high sensitivity, portability, and mature technology, and can achieve real-time monitoring, but it is greatly affected by the environment, can only measure locally, and is complex to install; optical fiber technology has high precision, anti-interference, and strong durability, and can also achieve long-distance measurement, but it is costly, difficult to maintain, and has high installation requirements; vibration and acceleration measurement technology has dynamic monitoring, versatility, and easy installation, but it also faces indirect measurement cumulative errors and is easily interfered by noise. In summary, the current monitoring of the total longitudinal bending moment of the hull urgently needs a high-precision, high-durability, anti-interference, economical, and easy-to-install sensor. Summary of the invention

[0004] The present invention proposes a device, method, terminal and medium for monitoring the total longitudinal bending moment of a hull, so as to solve the problems of high cost and low precision of the existing bending moment monitoring.

[0005] A device for monitoring the total longitudinal bending moment of a hull comprises a long baseline sensor, a hull bottom structure, a data receiving processor, a terminal and a medium. The long baseline sensor is fixedly installed on a point to be monitored on the hull bottom structure. The long baseline sensor is data-connected to the data receiving processor. The data receiving processor and the terminal are data-connected to the medium.

[0006] Furthermore, the long baseline sensor includes a sensor body, a high-rigidity iron pipe and a mounting component. The sensor body is fixedly connected to one end of the high-rigidity iron pipe, and the sensor body and the high-rigidity iron pipe are integrally fixed to the bottom structure of the hull through the mounting component.

[0007] Furthermore, the sensor body is a fiber Bragg grating sensor.

[0008] Furthermore, the mounting member includes a front-end mounting member and a rear-end mounting member.

[0009] The front-end mounting component includes a top seat of a fixing seat, a base of a fixing seat, an M12 hexagon socket screw and a plurality of M5 hexagon socket screws. A longitudinal through hole matching the M12 hexagon socket screw is provided in the base of the fixing seat. The M12 hexagon socket screw is screwed to the bottom structure of the hull through the through hole and is fully embedded in the through hole. The base of the fixing seat is pressed tightly against the bottom structure of the hull through the nut of the M12 hexagon socket screw. The top seat of the fixing seat is installed above the base of the fixing seat through a plurality of M5 hexagon socket screws, and the sensor body is clamped by the smooth curved surfaces of the top seat of the fixing seat and the inner surface of the base of the fixing seat;

[0010] The rear end mounting components include a universal joint, an M16 threaded rod and an M16 nut. A threaded hole matching the M16 threaded rod is opened at the other end of the high-rigidity iron pipe. The M16 threaded rod passes through the universal joint and is screwed to the threaded hole. The tail screw of the universal joint is screwed to the bottom structure of the hull. Multiple M16 nuts are screwed to the M16 threaded rod and the tail screw of the universal joint to fix the M16 threaded rod and the universal joint, the M16 threaded rod and the high-rigidity iron pipe, the universal joint and the bottom structure of the hull.

[0011] Furthermore, it also includes optical fiber. There are multiple long baseline sensors. Each long baseline sensor has an optical fiber interface on both sides of the sensor body. One end of the optical fiber is connected to the optical fiber interface, and the other end is connected to the data receiving processor.

[0012] Furthermore, it also includes a data line, and the data receiving processor is connected to the medium data through the transmission line and the terminal.

[0013] A method for monitoring the total longitudinal bending moment of a hull is applied to the above-mentioned device for monitoring the total longitudinal bending moment of a hull. The method for monitoring the total longitudinal bending moment of a hull comprises the following steps:

[0014] S1. Arrange a number of long baseline sensors at the points to be monitored on the bottom structure of the hull. Lead out two optical fibers from both sides of the sensor body of each long baseline sensor, connect and aggregate them in a data receiving processor, and then transmit them to the terminal and the medium through a data line;

[0015] S2. When the measured bottom structure of the hull is deformed, the distance between the two points where the long baseline sensor is fixed on the bottom structure of the hull changes accordingly. Since the high-rigidity iron pipe theoretically does not produce deformation, all the strain is concentrated on the sensor body. The sensor body senses the strain and temperature, and calculates the actual strain through the pre-calibrated displacement coefficient k, combined with the difference between the grating wavelength and the calibration wavelength during measurement, to achieve strain data collection;

[0016] S3. Assume that the longitudinal strain of the structure where the long baseline sensor (1) is installed is only determined by the total longitudinal bending moment M Vand transverse bending moment M H The strain does not exceed the proportional limit of the material. According to the beam bending theory and the pure bending assumption of the hull beam, the relationship between strain and bending moment is constructed and expressed in matrix form [K] 2×2 .{M} 2×1 ={ε} 2×1 , calculate the transfer matrix [K] based on the hull cross section 2×2 , the strain vector {ε} is obtained through structural monitoring 2×1 , and then use the direct inversion method to calculate the load vector {M} 2×1 , that is, the total longitudinal bending moment and transverse bending moment of the hull cross section are obtained.

[0017] Furthermore, in S2, when the measured hull bottom structure presents sagging, the distance between the fixed points on both sides of the long baseline sensor is compressed, and the deformation caused by the high-rigidity iron pipe is negligible, so the strain of the measurement length corresponding to the long baseline sensor is all collected in the sensor body, thereby measuring the corresponding strain ε; similarly, when the measured hull bottom structure presents arching, the distance between the fixed points on both sides of the long baseline sensor is stretched, and the strain of the measurement length corresponding to the long baseline sensor is all collected in the sensor body, thereby measuring the corresponding strain ε;

[0018] It is known that the variables of strain and temperature are linearly related to the grating wavelength variable Δλ. The coefficient k between the variables of strain and temperature and the grating wavelength variable Δλ is calibrated in advance before the test. The sensor grating wavelength λ is calibrated in advance before the measurement. The calibration is performed based on the initial values ​​of strain and temperature. Subsequently, during the operation of the sensor, the sensor grating wavelength λ varies with strain and temperature. The calculation method is as follows:

[0019]

[0020] Among them, λ d is the grating wavelength corresponding to the strain test; is the grating wavelength corresponding to the strain calibration; T is the grating wavelength corresponding to the test temperature; is the grating wavelength corresponding to the calibration temperature; k is the displacement coefficient;

[0021] In S3, regarding the relationship between strain and bending moment, the coordinates of A and B are (y A ,z A ) and (y B ,z B ), assuming that the longitudinal strain of the structure at the installation location of the long baseline sensor is only determined by the total longitudinal bending moment M V and transverse bending moment M H Caused by, and the strain does not exceed the proportional limit of the material, the linear superposition of the strain at the point where the long baseline sensor is installed is expressed as:

[0022]

[0023] Where E is the elastic modulus of the material, Ix and Iy are the moments of inertia of the cross section of the structure;

[0024] The transfer function of the bending moment calculation method [K] · {M} = {ε}, the transfer function [K] 2×2 .{M} 2×1 ={ε} 2×1 The matrix form of is:

[0025]

[0026] in is the transfer matrix, which represents the mapping relationship between the bending moment of the hull cross section and the longitudinal strain of the structure; is the load vector, i.e. the total longitudinal bending moment and transverse bending moment of the hull cross section; is the strain vector, i.e., the average longitudinal strain of the structure at the sensor installation location;

[0027] The moment of inertia Ix and Iy of the structural cross section and the coordinates of the sensor installation position are obtained according to the structural characteristics of the hull itself and the sensor installation position. The transfer matrix [K] 2×2 Calculated based on the cross section of the hull, the real-time strain vector {ε} is obtained during monitoring 2×1 , at this time the load vector is obtained by direct inversion method:

[0028]

[0029] A storage medium stores a computer program, which implements the above method when executed by a processor.

[0030] A terminal includes: a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the program to implement the above method.

[0031] Beneficial effects of the present invention: The present invention provides a device, method, terminal and medium for monitoring the total longitudinal bending moment of a hull, which converts the problem of long-distance bending moment identification into the problem of short-distance displacement identification. The long-baseline deck bending moment is converted into a short-baseline displacement measurement by transmitting the characteristic of high-rigidity iron pipes that do not produce elastic deformation and the universal joint to the fiber Bragg grating sensor. By constructing a transfer matrix [K] between the bending moment of the hull cross section and the longitudinal strain of the structure, the measured strain vector {ε} can be directly converted into a bending moment load vector {M}, achieving the purpose of identifying the bending moment based on local rather than full-field displacement information. Compared with traditional algorithms, it is simpler, faster and more efficient; compared with traditional stress-strain measurement methods, it has higher accuracy, stronger anti-interference and is easy to install; compared with optical fiber measurement methods, the cost is greatly reduced and the installation and maintenance are simpler. Combining optical fiber and data acquisition instrument can realize real-time distributed monitoring of the total longitudinal bending moment of the hull, providing strong data support for the evaluation of hull structural safety, fatigue damage, structural strength, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of a device for monitoring the total longitudinal bending moment of a hull;

[0033] Figure 2 This is the flow chart for monitoring the total longitudinal bending moment of the hull;

[0034] Figure 3 It is the structural diagram of the long baseline sensor;

[0035] Figure 4 It is a schematic diagram of the internal structure of the sensor body of the long baseline sensor;

[0036] Figure 5 This is the installation and disassembly diagram of the sensor body and front-end mounting components of the long baseline sensor;

[0037] Figure 6 This is a diagram showing the installation completion of the sensor body and front-end mounting components of the long baseline sensor;

[0038] Figure 7 This is the installation and disassembly diagram of the rear end mounting component of the long baseline sensor;

[0039] Figure 8 This is a diagram showing the completion of the installation of the rear end mounting components of the long baseline sensor;

[0040] Fig. 9 is the beam bending deformation diagram, where Fig. 9 (a) is the vertical bending deformation diagram; Fig. 9 (b) is the transverse bending deformation diagram;

[0041] Fig.10 Define a diagram for a ship's local coordinate system;

[0042] Fig.11 This is the working condition of the long baseline sensor when measuring bending moment;

[0043] Fig.12 This is the working principle diagram of the main fiber grating sensor of the long baseline sensor.

[0044] Among them, 1 is the long baseline sensor, 2 is the bottom structure of the hull, 3 is the data receiving processor, 4 is the terminal and medium, 5 is the optical fiber, 6 is the data cable, 7 is the sensor body, 8 is the high-rigidity iron pipe, 9 is the mounting component, L1 is the top seat of the fixing seat, L2 is the base of the fixing seat, L3 is the M12 hexagon socket screw, L4 is multiple M5 hexagon socket screws, L5 is the universal joint, L6 is the M16 threaded rod, and L7 is the M16 nut. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0046] Reference Figure 1-Figure 2 As shown, a device for monitoring the total longitudinal bending moment of a hull includes a long baseline sensor 1, a hull bottom structure 2, a data receiving processor 3, and a terminal and a medium 4. The long baseline sensor 1 is fixedly installed on the point to be monitored of the hull bottom structure 2, the long baseline sensor 1 is data-connected to the data receiving processor 3, and the data receiving processor 3 and the terminal and the medium 4 are data-connected.

[0047] Specifically, in the device for monitoring the total longitudinal bending moment of the hull of the present invention, the long baseline sensor 1 is fixedly installed on the monitoring point of the bottom structure 2 of the hull, which can accurately obtain the hull structure strain data, and transmit it to the data receiving processor 3, and then transmit it to the terminal and the medium 4, so as to realize the effective collection and transmission of data. Through this connection method, the total longitudinal bending moment of the hull can be monitored in real time, providing a reliable basis for the safety assessment of the hull structure, helping to timely discover potential safety hazards, and improving the safety of the hull operation. At the same time, it also provides strong data support for the research on hull fatigue damage, structural strength, etc.

[0048] During monitoring, the long baseline sensor 1 is arranged at the monitoring point of the bottom structure 2 of the hull. Optical fiber interfaces are provided on both sides of the sensor body of the long baseline sensor 1. Two optical fibers 5 are led out from the optical fiber interface of each long baseline sensor 1 and connected and aggregated in the data receiving processor 3, and then transmitted to the computer medium and terminal 4 through the data line 6.

[0049] Further, see Figure 3As shown, the long baseline sensor 1 includes a sensor body 7, a high-rigidity iron pipe 8 and a mounting component 9. The sensor body 7 is fixedly connected to one end of the high-rigidity iron pipe 8, and the whole formed by the sensor body 7 and the high-rigidity iron pipe 8 is fixed to the bottom structure 2 of the hull through the mounting component 9.

[0050] Specifically, the material of the high-rigidity iron pipe 8 itself has an elastic modulus higher than that of ordinary steel, and the structure is less likely to produce elastic deformation. The high-rigidity iron pipe 8 is used to connect the sensor body 7 and the universal joint L5 on the other side. The front end of the high-rigidity iron pipe 8 has a built-in M10 threaded hole for connecting the sensor body 7, and the rear end has a built-in M16 threaded hole for connecting the universal joint L5 through the M16 threaded rod L6. During testing, the high-rigidity iron pipe 8 of corresponding length can be adjusted or processed according to the size of the plate frame structure to be tested. Therefore, the long baseline sensor 1 involved in the present invention can be suitable for bending moment measurements of various sizes. It should be noted that the high-rigidity iron pipe 8 theoretically does not produce any deformation during operation.

[0051] Furthermore, the sensor body 7 is a fiber Bragg grating sensor.

[0052] Specifically, refer to Figure 4 As shown, in the long baseline sensor 1 involved in the present invention, the sensor body 7 is a fiber Bragg grating sensor, with a place on each side for connecting optical fibers, an interface S1 on one side is used to measure strain, an interface S2 on the other side is used for temperature compensation, and another side S4 is separately extended and provided with an M10 threaded rod that can be connected to a high-rigidity iron pipe 8. During measurement, the high-rigidity iron pipe 8 acts on the built-in spring device S3 through the threaded end. The set gauge length of the long baseline sensor 1 is 2m. During measurement, the displacement of the measured plate within the set gauge length is converted into the strain at the measuring end of the sensor. The strain and the external temperature jointly affect the grating wavelength Δλ in the sensor body 7, and the actual strain ε is obtained through the pre-calibrated displacement coefficient k.

[0053] Further, see Figure 5-Figure 8 As shown, the mounting member 9 includes a front-end mounting member and a rear-end mounting member.

[0054] Among them, refer to Figure 5-Figure 6 As shown, the front-end mounting component includes a fixing seat top seat L1, a fixing seat base L2, an M12 hexagon socket screw L3 and a plurality of M5 hexagon socket screws L4. A longitudinal through hole matching the M12 hexagon socket screw L3 is provided in the fixing seat base L2. The M12 hexagon socket screw L3 is screwed with the hull bottom structure 2 through the through hole and is completely embedded in the through hole. The fixing seat base L2 is pressed tightly against the hull bottom structure 2 through the nut of the M12 hexagon socket screw L3. The fixing seat top seat L1 is installed above the fixing seat base L2 through a plurality of M5 hexagon socket screws L4, and the sensor body 7 is clamped by the smooth curved surfaces of the inner surfaces of the fixing seat top seat L1 and the fixing seat base L2.

[0055] Reference Figure 7-Figure 8 As shown, the rear end mounting component includes a universal joint L5, an M16 threaded rod L6 and an M16 nut L7. The other end of the high-rigidity iron pipe 8 is provided with a threaded hole matching the M16 threaded rod L6. The M16 threaded rod L6 passes through the universal joint L5 and is screwed to the threaded hole. The tail screw of the universal joint L5 is screwed to the bottom structure 2 of the hull. Multiple M16 nuts L7 are screwed to the M16 threaded rod L6 and the tail screw of the universal joint L5 to fix the M16 threaded rod L6 and the universal joint L5, the M16 threaded rod L6 and the high-rigidity iron pipe 8, the universal joint L5 and the bottom structure 2 of the hull.

[0056] Further, see Figure 1 As shown, it also includes an optical fiber 5. There are multiple long baseline sensors 1. A fiber optic interface is provided on both sides of the sensor body 7 in each long baseline sensor 1. One end of the optical fiber 5 is connected to the fiber optic interface, and the other end is connected to the data receiving processor 3.

[0057] Further, see Figure 1 As shown, it also includes a data line 6, and the data receiving processor 3 is data-connected to the medium 4 through the transmission line 6 and the terminal.

[0058] Specifically, the optical fiber 5 and the data line 6 further improve the performance of the entire monitoring device. Multiple long baseline sensors 1 are connected to the data receiving processor 3 through the optical fiber 5. On the one hand, the advantages of optical fiber transmission signals, such as strong anti-interference ability, fast transmission speed, and low signal attenuation, are utilized to ensure that the strain data obtained from each sensor can be accurately and quickly transmitted to the data receiving processor 3, thereby improving the efficiency and accuracy of data acquisition. On the other hand, multiple sensors working simultaneously can monitor different positions of the hull, obtain more comprehensive information, and provide the possibility for more accurate analysis of the total longitudinal bending moment of the hull. The setting of the data line 6 realizes stable data transmission between the data receiving processor 3 and the terminal and the medium 7, which facilitates the subsequent processing, storage and analysis of the collected data.

[0059] A method for monitoring the total longitudinal bending moment of a hull is applied to the above-mentioned device for monitoring the total longitudinal bending moment of a hull. The method for monitoring the total longitudinal bending moment of a hull comprises the following steps:

[0060] S1, a plurality of long baseline sensors 1 are arranged at the points to be monitored on the bottom structure 2 of the hull, two optical fibers are led out from both sides of the sensor body 7 in each long baseline sensor 1, connected and aggregated in the data receiving processor 3, and then transmitted to the terminal and the medium 4 through the data line;

[0061] S2. When the measured hull bottom structure 2 is deformed, the distance between the two points where the long baseline sensor 2 is fixed on the hull bottom structure 2 changes accordingly. Since the high-rigidity iron pipe 8 theoretically does not produce deformation, all the strains are collected in the sensor body 7. The sensor body 7 senses the strain and temperature, and calculates the actual strain through the pre-calibrated displacement coefficient k and the difference between the grating wavelength and the calibration wavelength during measurement, thereby realizing strain data collection;

[0062] S3, assuming that the longitudinal strain of the structure where the long baseline sensor 1 is installed is only determined by the total longitudinal bending moment M V and transverse bending moment M H The strain does not exceed the proportional limit of the material. According to the beam bending theory and the pure bending assumption of the hull beam, the relationship between strain and bending moment is constructed and expressed in matrix form [K] 2×2 .{M} 2×1 ={ε} 2×1 , calculate the transfer matrix [K] based on the hull cross section 2×2 , the strain vector {ε} is obtained through structural monitoring 2×1 , and then use the direct inversion method to calculate the load vector {M} 2×1 , that is, the total longitudinal bending moment and transverse bending moment of the hull cross section are obtained.

[0063] Specifically, firstly, the present invention realizes efficient collection and stable transmission of strain data at different positions of the hull by reasonably arranging multiple long baseline sensors 1 at the monitoring points of the bottom structure 2 of the hull, and using optical fiber 5 and data line 6 to build a data transmission link, thereby providing a comprehensive and accurate data basis for subsequent analysis. Secondly, the characteristic of high-rigidity iron pipe 8 that does not produce deformation is utilized to concentrate the strain on the sensor body 7, and the actual strain is calculated in combination with the pre-calibrated displacement coefficient, thereby improving the accuracy of strain data acquisition. Furthermore, a mathematical model is constructed based on the beam bending theory and the pure bending assumption of the hull beam, and the bending moment is calculated by the direct inversion method, so that the total longitudinal bending moment and transverse bending moment of the hull cross section can be effectively and accurately deduced from the local strain data. The method is simple to operate as a whole, has high measurement accuracy, and efficient data processing. It can provide key support for hull structure safety assessment, fatigue damage analysis, etc., and effectively ensure the safe operation of ships under complex working conditions.

[0064] Further, in S2, when the measured hull bottom structure 2 presents sagging, the distance between the fixed points on both sides of the long baseline sensor 1 is compressed, and the deformation caused by the high-rigidity iron pipe 8 is negligible, so the strain of the measurement length corresponding to the long baseline sensor 1 is all collected in the sensor body 7, thereby measuring the corresponding strain ε; similarly, when the measured hull bottom structure 2 presents arching, the distance between the fixed points on both sides of the long baseline sensor 1 is stretched, and the strain of the measurement length corresponding to the long baseline sensor 1 is all collected in the sensor body 7, thereby measuring the corresponding strain ε;

[0065] It is known that the variables of strain and temperature are linearly related to the grating wavelength variable Δλ. The coefficient k between the variables of strain and temperature and the grating wavelength variable Δλ is calibrated in advance before the test. The sensor grating wavelength λ is calibrated in advance before the measurement. The calibration is performed based on the initial values ​​of strain and temperature. Subsequently, during the operation of the sensor, the sensor grating wavelength λ varies with strain and temperature. The calculation method is as follows:

[0066]

[0067] Among them, λ d is the grating wavelength corresponding to the strain test; is the grating wavelength corresponding to the strain calibration; T is the grating wavelength corresponding to the test temperature; is the grating wavelength corresponding to the calibration temperature; k is the displacement coefficient;

[0068] In S3, regarding the relationship between strain and bending moment, the coordinates of A and B are (y A ,z A ) and (y B ,z B ), assuming that the longitudinal strain of the structure at the installation location of the long baseline sensor 1 is only determined by the total longitudinal bending moment M V and transverse bending moment M H Caused by, and the strain does not exceed the proportional limit of the material, the strain linear superposition at the point where the long baseline sensor 1 is installed is expressed as:

[0069]

[0070] Where E is the elastic modulus of the material, Ix and Iy are the moments of inertia of the cross section of the structure;

[0071] The transfer function of the bending moment calculation method [K] · {M} = {ε}, the transfer function [K] 2×2 .{M} 2×1 ={ε} 2×1 The matrix form of is:

[0072]

[0073] in is the transfer matrix, which represents the mapping relationship between the bending moment of the hull cross section and the longitudinal strain of the structure; is the load vector, i.e. the total longitudinal bending moment and transverse bending moment of the hull cross section; is the strain vector, i.e., the average longitudinal strain of the structure at the sensor installation location;

[0074] The moment of inertia Ix and Iy of the structural cross section and the coordinates of the sensor installation position are obtained according to the structural characteristics of the hull itself and the sensor installation position. The transfer matrix [K] 2×2 Calculated based on the cross section of the hull, the real-time strain vector {ε} is obtained during monitoring 2×1 , at this time the load vector is obtained by direct inversion method:

[0075]

[0076] Specifically, the present invention relates to a method for monitoring the total longitudinal bending moment of a hull. The reasonable application of online monitoring of hull strength can effectively improve the safety of the hull structure, wherein monitoring the wave bending moment actually borne by the hull beam is a major monitoring method for hull strength monitoring. The indirect monitoring system for wave bending moment of non-large opening ship types based on traditional methods has been used in engineering for many years. It mainly monitors the longitudinal average strain of the hull structure through a long baseline strain gauge arranged at the midship position, and then calculates the total longitudinal bending moment and transverse bending moment of the monitored cross section based on the pure bending assumption of the hull beam.

[0077] Combination Fig. 9 , this figure is a beam bending deformation diagram. In beam bending theory, the longitudinal strain can be considered to be linearly distributed along the thickness direction, and the strain at the neutral axis is zero. Therefore, the longitudinal strain can be expressed as:

[0078]

[0079] In the pure bending of the hull beam, it is believed that it also obeys the pure bending deformation law of ordinary beams. Fig. 9 (a) and Fig. 9 (b) Strictly speaking, within the proportional limit of the material, the longitudinal strain caused by the vertical bending moment and the transverse bending moment of the hull beam at the same point can be linearly superimposed. Within the elastic limit of the material, the longitudinal strain caused by the vertical bending moment and the transverse bending moment of the hull beam at the same point can be approximately considered to be linearly superimposed.

[0080] Combination Fig.10 , this figure is a definition diagram of the local coordinate system of a certain ship. The local coordinate system of the monitored cross section is defined as follows: the origin of the coordinate system is at the centroid of the cross section, the positive direction of the Z axis is upward, the positive direction of the Y axis points to the port side, and the positive direction of the X axis points to the bow. In addition, the total longitudinal bending moment can make the hull arch positive, and the transverse bending moment can make the hull arch to the port side positive.

[0081] If long baseline strain gauges are installed at two locations on the hull structure to monitor the actual strain, the coordinates of the midpoints A and B of the long baseline strain gauges are (y A ,z A ) and (y B ,z B ). Assume that the longitudinal strain of the structure at the sensor installation location is only determined by the total longitudinal bending moment M Vand transverse bending moment M H If the strain does not exceed the proportional limit of the material, the strain at the point where the sensor is installed can be expressed by linear superposition:

[0082]

[0083] Express it in matrix form:

[0084]

[0085] The above formula can be simplified to: [K] 2×2 .{M} 2×1 ={ε} 2×1

[0086] Where:

[0087] is the transfer matrix, which represents the mapping relationship between the bending moment of the hull cross section and the longitudinal strain of the structure;

[0088] is the load vector, i.e. the total longitudinal bending moment and transverse bending moment of the hull cross section;

[0089] is the strain vector, i.e., the average longitudinal strain of the structure at the sensor installation location.

[0090] Transfer matrix [K] 2×2 It can be calculated based on the cross section of the hull, that is, it is only necessary to obtain the inertia moments Ix and Iy of the cross section of the structure and the coordinates of the sensor installation position. Strain vector {ε} 2×1 Can be obtained through structural monitoring. Transfer matrix [K] 2×2 and the strain vector {ε} 2×1 After obtaining, the load vector {M} 2×1 It can be obtained by direct inversion method:

[0091]

[0092] Combination Fig.11 , This figure shows the working condition of the long baseline sensor 1 when measuring bending moment.

[0093] Specifically, when the measured hull bottom structure 2 is sagging, the distance between the two side fixed points of the long baseline sensor is compressed, and the deformation caused by the high-rigidity steel pipe can be ignored, so the strain of the measurement length corresponding to the long baseline sensor 1 is all collected in the sensor body 7, thereby measuring the corresponding strain ε. Similarly, when the measured hull bottom structure 2 is arching, the distance between the two side fixed points of the long baseline sensor 1 is stretched, and the strain of the measurement length corresponding to the long baseline sensor 1 is all collected in the sensor body 7, thereby measuring the corresponding strain ε.

[0094] Combination Fig.12 , This figure is a working principle diagram of the main fiber Bragg grating sensor of the long baseline sensor 1. The final output of the sensor is strain ε, which is determined by strain and temperature compensation.

[0095] Specifically, the sensor body 7 can sense three basic physical quantities, namely stress, strain and temperature. The sensor body 7 is wrapped in a stainless steel shell. The quantity that mainly affects the grating wavelength is strain, followed by temperature. The deformation of the sensor itself is not considered in the experiment, so the influence of stress is not taken into account. It is known that the variables of strain and temperature are linearly related to the grating wavelength variable Δλ, and the coefficient k between them can be calibrated in advance before testing. The sensor grating wavelength λ is calibrated in advance before measurement, and the initial values ​​of strain and temperature are calibrated. Then, during the operation of the sensor, the grating wavelength λ differs with strain and temperature. The specific physical quantity calculation method is as follows:

[0096]

[0097] in

[0098] λ d is the grating wavelength corresponding to the strain test;

[0099] is the grating wavelength corresponding to the strain calibration;

[0100] λ T is the grating wavelength corresponding to the test temperature;

[0101] is the grating wavelength corresponding to the calibration temperature;

[0102] k is the displacement coefficient.

[0103] A storage medium stores a computer program, which implements the above method when executed by a processor.

[0104] Specifically, the computer program for the method of monitoring the total longitudinal bending moment of the hull is stored therein, which can ensure that the method can run stably under different processor environments. With the help of the storage medium, the program code of the monitoring method can be easily called by the processor without the need to repeatedly write code, which improves the efficiency of the development and deployment of the monitoring system. In addition, the storage medium facilitates the updating and maintenance of the program. If there is a need to optimize the monitoring method, it only needs to update the program in the storage medium to quickly apply the new function.

[0105] A terminal includes: a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the program to implement the above method.

[0106] Specifically, the memory integrated in the present invention is used to store computer programs for implementing the monitoring method and various types of data collected, to ensure the safe storage of data and to call them at any time. The processor executes the program stored in the memory to implement various operations of monitoring the total longitudinal bending moment of the hull, from data collection and processing to the final calculation of the total longitudinal bending moment and the lateral bending moment, to complete the entire monitoring process, and ensure the automation and intelligent operation of the monitoring work. The terminal is compatible with different hardware environments, has strong flexibility, and is convenient for deployment and application on a variety of ship equipment. Through the efficient data processing capability of the processor and the stable data storage function of the memory, the terminal can analyze and process the monitoring data in a timely and accurate manner, and provide ship management personnel with intuitive and effective data results, which helps them to grasp the stress condition of the hull in a timely manner, make scientific decisions, and thus ensure the safe and stable operation of the ship.

[0107] The mounting components of the monitoring device of the present invention are exquisitely designed, and the front and rear mounting components are tightly matched to firmly fix the long baseline sensor 1, ensuring accurate measurement without external interference; multiple long baseline sensors 1 are combined with optical fiber 5 and data line 6 to achieve efficient collection and stable transmission of strain data at different positions of the hull, ensuring the comprehensiveness and accuracy of the data. The monitoring method uses the characteristics of the high-rigidity iron pipe 8 to accurately collect strain data, and combines mathematical models to calculate bending moments. The operation is simple and accurate. The storage medium can conveniently store and update the monitoring program, and the processor and memory of the terminal work together to realize the automation and intelligence of the monitoring process.

[0108] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In addition, "front", "back", "left", "right", "upper" and "lower" in this article are all referenced to the placement state shown in the accompanying drawings.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for monitoring the total longitudinal bending moment of a hull, characterized in that: The invention comprises a long baseline sensor (1), a hull bottom structure (2), a data receiving processor (3), a terminal and a medium (4); the long baseline sensor (1) is fixedly installed on a point to be monitored on the hull bottom structure (2); the long baseline sensor (1) is data-connected to the data receiving processor (3); and the data receiving processor (3) and the terminal are data-connected to the medium (4).

2. A device for monitoring the total longitudinal bending moment of a hull according to claim 1, characterized in that: The long baseline sensor (1) comprises a sensor body (7), a high-rigidity iron pipe (8) and a mounting component (9); the sensor body (7) is fixedly connected to one end of the high-rigidity iron pipe (8); and the sensor body (7) and the high-rigidity iron pipe (8) are integrally fixed to a hull bottom structure (2) via the mounting component (9).

3. A device for monitoring the total longitudinal bending moment of a hull according to claim 2, characterized in that: The sensor body (7) is a fiber Bragg grating sensor.

4. A device for monitoring the total longitudinal bending moment of a hull according to claim 3, characterized in that: The mounting member (9) comprises a front mounting member and a rear mounting member, The front-end mounting component comprises a fixing seat top seat (L1), a fixing seat base (L2), an M12 hexagon socket screw (L3) and a plurality of M5 hexagon socket screws (L4); a longitudinal through hole matching the M12 hexagon socket screw (L3) is provided in the fixing seat base (L2); the M12 hexagon socket screw (L3) is screwed to the hull bottom structure (2) through the through hole and is completely embedded in the through hole; the fixing seat base (L2) is pressed tightly against the hull bottom structure (2) through the nut of the M12 hexagon socket screw (L3); the fixing seat top seat (L1) is installed above the fixing seat base (L2) through a plurality of M5 hexagon socket screws (L4); and the sensor body (7) is clamped by the smooth curved surfaces of the inner surfaces of the fixing seat top seat (L1) and the fixing seat base (L2); The rear end mounting component comprises a universal joint (L5), an M16 threaded rod (L6) and an M16 nut (L7); the other end of the high-rigidity iron pipe (8) is provided with a threaded hole matching the M16 threaded rod (L6); the M16 threaded rod (L6) passes through the universal joint (L5) and is screwed to the threaded hole; the tail screw of the universal joint (L5) is screwed to the hull bottom structure (2); a plurality of M16 nuts (L7) are screwed to the M16 threaded rod (L6) and the tail screw of the universal joint (L5) to fix the M16 threaded rod (L6) and the universal joint (L5), the M16 threaded rod (L6) and the high-rigidity iron pipe (8), the universal joint (L5) and the hull bottom structure (2).

5. The device for monitoring the total longitudinal bending moment of a hull according to claim 3, characterized in that: It also includes an optical fiber (5), a plurality of long baseline sensors (1), and an optical fiber interface is provided on both sides of a sensor body (7) in each long baseline sensor (1). One end of the optical fiber (5) is connected to the optical fiber interface, and the other end is connected to a data receiving processor (3).

6. The device for monitoring the total longitudinal bending moment of a hull according to claim 1, characterized in that: It also includes a data line (6), and the data receiving processor (3) is data-connected to the medium (4) via the transmission line (6) and the terminal.

7. A method for monitoring the total longitudinal bending moment of a hull, applied to a device for monitoring the total longitudinal bending moment of a hull as shown in claims 1-6, characterized in that: The method for monitoring the total longitudinal bending moment of a hull comprises the following steps: S1. Arrange a plurality of long baseline sensors (1) at the points to be monitored on the bottom structure (2) of the hull. Lead out two optical fibers from both sides of the sensor body (7) in each long baseline sensor (1), connect and aggregate them to the data receiving processor (3), and then transmit them to the terminal and the medium (4) through the data line; S2. When the measured hull bottom structure (2) is deformed, the distance between the two points where the long baseline sensor (2) is fixed on the hull bottom structure (2) changes accordingly. Since the high-rigidity iron pipe (8) theoretically does not produce deformation, all the strains are collected in the sensor body (7). The sensor body (7) senses the strain and temperature, and calculates the actual strain through the pre-calibrated displacement coefficient k combined with the difference between the grating wavelength and the calibration wavelength during measurement, thereby realizing strain data collection; S3. Assume that the longitudinal strain of the structure where the long baseline sensor (1) is installed is only determined by the total longitudinal bending moment M V and transverse bending moment M H The strain does not exceed the proportional limit of the material. According to the beam bending theory and the pure bending assumption of the hull beam, the relationship between strain and bending moment is constructed and expressed in matrix form [K] 2×2 .{M} 2×1 ={ε} 2×1 , calculate the transfer matrix [K] based on the hull cross section 2×2 , the strain vector {ε} is obtained by structural monitoring 2×1 , and then use the direct inversion method to calculate the load vector {M} 2×1 , that is, the total longitudinal bending moment and transverse bending moment of the hull cross section are obtained.

8. A method for monitoring the total longitudinal bending moment of a hull according to claim 7, characterized in that: In S2, when the measured hull bottom structure (2) is in a sagging state, the distance between the fixed points on both sides of the long baseline sensor (1) is compressed, and the deformation caused by the high-rigidity iron pipe (8) is negligible, so that the strain of the measurement length corresponding to the long baseline sensor (1) is all collected in the sensor body (7), thereby measuring the corresponding strain ε; similarly, when the measured hull bottom structure (2) is in a bulging state, the distance between the fixed points on both sides of the long baseline sensor (1) is stretched, and the strain of the measurement length corresponding to the long baseline sensor (1) is all collected in the sensor body (7), thereby measuring the corresponding strain ε; It is known that the variables of strain and temperature are linearly related to the grating wavelength variable Δλ. The coefficient k between the variables of strain and temperature and the grating wavelength variable Δλ is calibrated in advance before the test. The sensor grating wavelength λ is calibrated in advance before the measurement. The calibration is performed based on the initial values ​​of strain and temperature. Subsequently, during the operation of the sensor, the sensor grating wavelength λ varies with strain and temperature. The calculation method is as follows: Among them, λ d is the grating wavelength corresponding to the strain test; is the grating wavelength corresponding to the strain calibration; T is the grating wavelength corresponding to the test temperature; is the grating wavelength corresponding to the calibration temperature; k is the displacement coefficient; In S3, regarding the relationship between strain and bending moment, the coordinates of A and B are (y A ,z A ) and (y B ,z B ), assuming that the longitudinal strain of the structure at the installation location of the long baseline sensor (1) is only determined by the total longitudinal bending moment M V and transverse bending moment M H The strain caused by the long baseline sensor (1) at the installation position is expressed as follows: Where E is the elastic modulus of the material, Ix and Iy are the moments of inertia of the cross section of the structure; The transfer function of the bending moment calculation method [K] · {M} = {ε}, the transfer function [K] 2×2 .{M} 2×1 ={ε} 2×1 The matrix form of is: in is the transfer matrix, which represents the mapping relationship between the bending moment of the hull cross section and the longitudinal strain of the structure; is the load vector, i.e. the total longitudinal bending moment and transverse bending moment of the hull cross section; is the strain vector, i.e., the average longitudinal strain of the structure at the sensor installation location; The moment of inertia Ix and Iy of the structural cross section and the coordinates of the sensor installation position are obtained according to the structural characteristics of the hull itself and the sensor installation position. The transfer matrix [K] 2×2 Calculated based on the cross section of the hull, the real-time strain vector {ε} is obtained during monitoring 2×1 , at this time the load vector is obtained by direct inversion method:

9. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 7 to 8 is implemented.

10. A terminal, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method according to any one of claims 7 to 8.

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