System and method for monitoring full-field deformation of cylindrical shell structure under hydrostatic pressure

Abstract

The invention discloses a full-field deformation monitoring system and method for a cylindrical shell structure under hydrostatic pressure, and belongs to the field of deformation monitoring. Comprising the steps that strain sensors are arranged on the outer surface of equipment to be detected, strain of arrangement points is monitored, a radial strain continuous distribution diagram is drawn based on a cubic spline curve fitting algorithm, and the deformation condition of the cylindrical shell structure is monitored; and a pressure sensor is arranged at the hydraulic cabin to monitor the relationship between the strain and the pressure. According to the invention, full-field monitoring of the cylindrical shell can be realized, the strain and pressure change can be monitored in real time, and the method can be used for monitoring the real-time deformation of the surface of the cylindrical shell structure in an internal or external hydrostatic pressure environment.

Description

Technical Field

[0001] The present invention belongs to the field of deformation monitoring, and in particular relates to a full-field deformation monitoring system and method for a cylindrical shell structure under hydrostatic pressure. Background Art

[0002] During internal or external pressure tests on large equipment like pressure-resistant cylindrical shells, the high-pressure, sealed environment of the test piece makes it difficult to monitor its deformation in real time, hindering effective real-time adjustment of experimental parameters based on deformation size and area. Traditional solutions, such as installing specialized cameras, are only effective for lower pressures and can compromise the sealing of the test equipment. Currently, there is no effective solution for monitoring deformation under higher pressures. Summary of the Invention

[0003] Aiming to solve the problem of micro-deformation monitoring of large cylindrical shell structures under hydrostatic pressure conditions, the present invention proposes a full-field deformation monitoring system for cylindrical shell structures, which can monitor the deformation of the cylindrical shell in real time.

[0004] The present invention provides a full-field deformation monitoring system for a cylindrical shell structure under hydrostatic pressure, comprising: a cylindrical shell of a device to be tested;

[0005] The data acquisition module includes arranging strain sensors on the external surface of the device to be tested to realize real-time strain monitoring and collection at the measuring point;

[0006] An analog-to-digital conversion module is connected to the data acquisition module; the analog-to-digital conversion module includes an electrical / optical signal processing instrument for converting analog signals into standard coded digital signals;

[0007] The data processing module decodes the received digital signal to obtain the real-time radial strain of the cylindrical shell;

[0008] The monitoring module is used to generate and display a continuous distribution diagram of radial strain based on the cubic spline curve fitting algorithm to monitor the deformation of the cylindrical shell structure.

[0009] Furthermore, the radial strain continuous distribution diagram includes a two-dimensional cloud diagram, and the two-dimensional cloud diagram is the corresponding relationship between the entire surface of the cylindrical shell and the radial deformation.

[0010] Furthermore, the data acquisition module also includes a pressure sensor arranged on the surface of the water ballast tank to monitor and collect the ambient pressure; the analog-to-digital conversion module also includes an analog-to-digital converter for converting the pressure analog signal into a standard coded digital signal.

[0011] Furthermore, the monitoring module generates and displays a pressure and radial strain graph.

[0012] The present invention also provides a test method for a full-field deformation monitoring system of a cylindrical shell structure under hydrostatic pressure, comprising the following steps:

[0013] Arrange multiple groups of hoop strain sensors on the surface of the cylindrical shell to obtain the hoop strain of the measuring point;

[0014] Arrange pressure sensors at the water ballast tank to obtain pressure data;

[0015] According to the position information and measurement values of the measuring points, images such as the radial strain continuous distribution diagram and the pressure and radial deformation curve diagram are drawn based on the cubic spline curve fitting algorithm.

[0016] Furthermore, the measuring points are arranged on the surface of the cylindrical shell in the circumferential direction; strain gauges or fiber grating sensors for measuring strain are arranged at the measuring points; the circumferential distance between the strain sensors for measuring strain does not exceed the radius of the cylindrical shell, and the axial distance does not exceed 1.5 times the radius of the cylindrical shell; the pressure sensor for measuring pressure is arranged on the surface of the water ballast tank, and the horizontal height does not exceed the top and bottom ends of the equipment to be measured.

[0017] Furthermore, when the deformation form is relatively simple and the strain is relatively small, the radial deformation u of any angle θ is r (θ) is:

[0018] u r (θ)=S(θ)r

[0019] In the case of complex deformation, the radial deformation u r (θ) is the numerical solution of the following differential equation:

[0020]

[0021] Where θ is the circumferential angle of the cylindrical shell structure, u r (θ) is a function representing the radial deformation of the cylindrical shell; r is the radius of the cylindrical shell structure; t is the radius of the cylindrical shell structure; S(θ) is a function representing the circumferential strain of the cylindrical shell.

[0022] Furthermore, the function S(θ) of the circumferential strain of the cylindrical shell is: for each set of circumferential measuring points, the angle of the measuring point is θ ε , the corresponding strain measurement value is ε(θ ε ); Based on the angle θ of the measuring point ε The cylindrical shell is divided into several small segments, and the strain function S of each segment is i (θ) is a cubic power function, and the function value, first-order derivative value, and second-order derivative value of the adjacent segments at adjacent positions are equal, that is:

[0023]

[0024] S i (θ ε )=S i+1 (θ ε )=ε(θ ε )

[0025] S′ i (θ ε )=S′ i+1 (θ ε )

[0026] S″ i (θ ε )=S i+1 (θ ε )

[0027] The strain function S of each segment can be obtained by simultaneous solution i (θ), the strain function S(θ) is obtained by S i (θ) is a piecewise function.

[0028] Furthermore, the cylindrical shell has no section where strain sensors are arranged, and the strain function S of the section position of each group of strain sensors is m (θ) is calculated based on the hoop strain function S(θ) of the cylindrical shell of this section:

[0029]

[0030] Among them, ξ m It is the reciprocal of the square of the axial distance between the section and each group of circumferential measuring points.

[0031] The beneficial effects of the present invention are:

[0032] The full-field deformation monitoring system for cylindrical shell structures provided by the present invention can accurately and in real time provide the deformation status of the cylindrical shell structure through monitoring in a high-pressure sealed environment, and monitor the overall deformation of the cylindrical shell in real time; the monitoring system realizes real-time strain and pressure signal processing, and can display deformation cloud maps and local deformation; it is used in related fields such as scientific research experiments, pressure-bearing structure optimization and deformation monitoring of large containers, breaking through the limitations of traditional optical and mechanical methods that are difficult to deploy and operate stably under high-pressure conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the overall structural block diagram of the full-field deformation monitoring system for cylindrical shell structures of the present invention;

[0034] Figure 2 This is a diagram showing the arrangement of strain gauges on the surface of a cylindrical shell according to the present invention;

[0035] Figure 3A two-dimensional cloud diagram of the surface strain of a cylindrical shell according to an embodiment of the present invention;

[0036] Figure 4 This is a radial deformation diagram of the cross section of a cylindrical shell according to an embodiment of the present invention;

[0037] Figure 5 This is a curve diagram showing the deformation of the collection point of the cylindrical shell as a function of pressure in an embodiment of the present invention;

[0038] Figure 6 This is a graph showing the deformation of a collection point of a cylindrical shell over time according to an embodiment of the present invention;

[0039] Figure 7 This is a graph showing the hydrostatic pressure of a cylindrical shell versus time according to an embodiment of the present invention.

[0040] The accompanying drawings are marked as follows: 1. Water ballast chamber; 2. Experimental piece; 3. Strain gauge; 4. Strain gauge; 5. Pressure gauge; 6. Digital-to-analog converter; 7. Computer; 8. Monitoring software. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application.

[0042] A full-field deformation monitoring system for a cylindrical shell structure under hydrostatic pressure includes: (1) an experimental device, (2) a strain measurement unit, (3) a pressure measurement unit, and (4) a signal processing and monitoring software unit. The strain measurement unit and the pressure measurement unit are respectively connected to the experimental device and transmit the collected strain and pressure signals to the signal processing and monitoring software 8.

[0043] The experimental equipment includes an experimental piece and an experimental control system. The experimental piece is a structure to be tested with a cylindrical shell surface. The experimental control system can adjust the pressure as needed.

[0044] The strain measurement section includes sensors (strain gauges or fiber Bragg grating sensors) and electrical / optical signal processing instruments (strain gauges or fiber optic signal demodulators). The signal processing instruments use the same signal transmission encoding as the monitoring software, can establish a TCP connection with the computer, and package the strain values into binary data according to the IEEE754 specification and send them to the computer at regular intervals.

[0045] The pressure measurement section includes an electronic pressure sensor and a corresponding analog-to-digital converter that sends IEEE754-encoded pressure data to the monitoring software either periodically or upon receiving a query signal.

[0046] The monitoring software displays the deformation of the test piece in real time, facilitating control of the experimental process and responding to various emergencies. Upon receiving encoded circumferential / axial strain data, it sends a query signal to the pressure measurement unit, converting the collected encoded strain and pressure data into a set of directly usable deformation data. The collected strain values can be parsed from the received binary data according to the encoding rules.

[0047] A test method for a full-field deformation monitoring system for a cylindrical shell structure under hydrostatic pressure includes: placing a cylindrical shell test piece inside a water pressure chamber, and evenly arranging and pasting strain gauges on the surface of the cylindrical shell in the circumferential and longitudinal directions, collecting the circumferential strain of the cylindrical shell measuring points in real time, and sealing the water pressure chamber. The monitoring software connects the electrical / optical signal processing instrument through the strain sensor and sends the data to the computer at a set sampling frequency; the digital-to-analog converter exchanges data with the pressure sensor, and the digital-to-analog converter can send the pressure signal to the computer at regular intervals or when receiving a query signal. The circumferential distance between the strain sensors measuring strain does not exceed the radius of the cylindrical shell, and the axial distance does not exceed 1.5 times the radius of the cylindrical shell; the pressure sensor measuring pressure is arranged next to the test piece, and the horizontal height does not exceed the top and bottom ends of the device to be tested.

[0048] Calculate the radial strain at the measuring point based on the obtained circumferential strain:

[0049] When the deformation form is relatively simple and the strain is relatively small, the radial deformation u of any angle θ is r (θ) is:

[0050] u r (θ)=S(θ)r

[0051] In the case of complex deformation, the radial deformation u r (θ) is the numerical solution of the following differential equation:

[0052]

[0053] Where θ is the circumferential angle of the cylindrical shell structure, u r (θ) is a function representing the radial deformation of the cylindrical shell; r is the radius of the cylindrical shell structure; t is the radius of the cylindrical shell structure; S(θ) is a function representing the circumferential strain of the cylindrical shell.

[0054] The calculation method of the cylindrical shell hoop strain function S(θ) is as follows: for each set of hoop measuring points, the angle of the measuring point is recorded as θ ε , the corresponding strain measurement value is recorded as ε(θ ε ). Based on the angle θ of the measuring point ε The cylindrical shell is divided into several small segments, and the strain function S of each segment is i (θ) is a cubic power function, and the function value, first-order derivative value, and second-order derivative value of the adjacent segments at adjacent positions are equal, that is:

[0055]

[0056] S i (θ ε )=S i+1 (θ ε )=ε(θ ε )

[0057] S′ i (θ ε )=S′ i+1 (θ ε )

[0058] S″ i (θ ε )=S″ i+1 (θ ε )

[0059] The strain function S of each segment can be obtained by simultaneous solution i (θ), the strain function S(θ) is obtained by S i (θ) is a piecewise function.

[0060] For the cross section without strain sensors, calculate the strain function of each group of strain sensor cross section positions, denoted as S m (θ); calculate the inverse of the square of the axial distance between the section and each group of circumferential measuring points, recorded as ξ m The calculation method of the hoop strain function S(θ) of the cylindrical shell with this cross section is:

[0061]

[0062] After receiving the data from the strain gauge 4, the monitoring software 8 sends a query signal to the analog-to-digital converter 6 to obtain the current pressure value. At the same time, the received data is processed to draw a curve of the deformation of the cylindrical shell at the collection point versus pressure.

[0063] Example 1

[0064] A full-field deformation monitoring system for cylindrical shell structures under hydrostatic pressure, such as Figure 1 As shown, it includes: (1) experimental equipment: water pressure chamber 1, test piece 2; (2) strain measurement part: strain gauge 3, strain meter 4; (3) pressure measurement part: pressure gauge 5, digital-to-analog converter 6; (4) signal processing and monitoring part: computer 7 and monitoring software 8.

[0065] The test piece needs to be surface treated to accommodate the strain gauges. The strain gauges should be arranged as dispersed as possible to cover the entire surface. A feasible strain gauge arrangement scheme is shown in the attached figure. Figure 2 shown.

[0066] The hydroballast chamber 1 is equipped with a pressure control function. After the test piece 2 is affixed with a strain gauge 3, it is placed inside the hydroballast chamber 1 and sealed. Monitoring software acquires strain and pressure data via a strain gauge 4 connected to the strain gauge 3 and an analog-to-digital converter 6 that exchanges data with a pressure gauge 5. The strain gauge 4 can transmit data to a computer 7 at a set sampling frequency, and the analog-to-digital converter 6 can transmit pressure signals to the computer 7 at a set time or upon receiving a query signal.

[0067] According to the actual conditions of the test, set the size parameters of the test piece 2, the strain gauge layout position and the test parameters of the pressure measurement sensitivity; Figure 1 After the equipment is installed and the instrument is connected, the monitoring software 8 receives the data sent by the strain gauge 4 and sends a query signal to the analog-to-digital converter 6 to obtain the current pressure value. At the same time, the received data is processed, the radial deformation of the cylindrical shell is plotted in the form of a contour map, and the (absolute value) maximum deformation of the cross section is displayed. Figure 4 Based on the cubic spline curve fitting algorithm, a continuous distribution diagram of radial strain is drawn to monitor the deformation of the cylindrical shell structure. Figure 3 As shown. Please draw the situation through the changes of strain and pressure as shown Figure 5 The deformation curve of the sampling point is shown as the curve of pressure change; according to the changes of deformation, pressure and time, the following Figure 6 、 7 shown.

[0068] In summary, the present invention provides a full-field deformation monitoring system for a cylindrical shell structure, which can be used to monitor the real-time deformation of the surface of a cylindrical shell structure under internal or external hydrostatic pressure environments.

[0069] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0070] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A full-field deformation monitoring system for cylindrical shell structures under hydrostatic pressure, characterized in that: include: Cylindrical shell of the device under test; The data acquisition module includes arranging strain sensors on the external surface of the device to be tested to realize real-time strain monitoring and collection at the measuring point; An analog-to-digital conversion module is connected to the data acquisition module; the analog-to-digital conversion module includes an electrical / optical signal processing instrument for converting analog signals into standard coded digital signals; The data processing module decodes the received digital signal to obtain the real-time radial strain of the cylindrical shell; The monitoring module is used to generate and display a continuous distribution diagram of radial strain based on the cubic spline curve fitting algorithm to monitor the deformation of the cylindrical shell structure.

2. The full-field deformation monitoring system for cylindrical shell structures under hydrostatic pressure according to claim 1 is characterized in that: The radial strain continuous distribution diagram includes a two-dimensional cloud diagram, and the two-dimensional cloud diagram is the corresponding relationship between the entire surface of the cylindrical shell and the radial deformation.

3. The full-field deformation monitoring system for cylindrical shell structures under hydrostatic pressure according to claim 1 is characterized in that: The data acquisition module also includes a pressure sensor arranged on the surface of the water ballast tank to monitor and collect the ambient pressure in the water tank; the analog-to-digital conversion module also includes an analog-to-digital converter for converting the pressure analog signal into a standard coded digital signal.

4. The full-field deformation monitoring system for cylindrical shell structures under hydrostatic pressure according to claim 3 is characterized in that: The monitoring module generates and displays a graph of pressure and radial strain.

5. A test method for a full-field deformation monitoring system for a cylindrical shell structure under hydrostatic pressure as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: Arrange multiple groups of hoop strain sensors on the surface of the cylindrical shell to obtain the hoop strain of the measuring point; Arrange pressure sensors at the water ballast tank to obtain pressure data; According to the position information and measurement values of the measuring points, images such as the radial strain continuous distribution diagram and the pressure and radial deformation curve diagram are drawn based on the cubic spline curve fitting algorithm.

6. The test method of the full-field deformation monitoring system of a cylindrical shell structure under hydrostatic pressure according to claim 5 is characterized in that: The measuring points are arranged on the surface of the cylindrical shell in the circumferential direction; strain gauges or fiber grating sensors for measuring strain are arranged at the measuring points; the circumferential distance between the strain sensors for measuring strain does not exceed the radius of the cylindrical shell, and the axial distance does not exceed 1.5 times the radius of the cylindrical shell; the pressure sensors for measuring pressure are arranged on the surface of the water ballast tank, and the horizontal height does not exceed the top and bottom ends of the cylindrical shell.

7. The test method of the full-field deformation monitoring system for cylindrical shell structures under hydrostatic pressure according to claim 5 is characterized in that: When the deformation form is relatively simple and the strain is relatively small, the radial deformation u of any angle θ is r (θ) is: you r (θ)=S(θ)r In the case of complex deformation, the radial deformation u r (θ) is the numerical solution of the following differential equation: Where θ is the circumferential angle of the cylindrical shell structure, u r (θ) is a function representing the radial deformation of the cylindrical shell; r is the radius of the cylindrical shell structure; t is the radius of the cylindrical shell structure; S(θ) is a function representing the circumferential strain of the cylindrical shell.

8. The test method of the full-field deformation monitoring system for cylindrical shell structures under hydrostatic pressure according to claim 7 is characterized in that: The function S(θ) of the circumferential strain of the cylindrical shell is: For each set of circumferential measuring points, the angle of the measuring point is θ ε , the corresponding strain measurement value is ε(θ ε ); Based on the angle θ of the measuring point ε The cylindrical shell is divided into several small segments, and the strain function S of each segment is i (θ) is a cubic power function, and the function value, first-order derivative value, and second-order derivative value of the adjacent segments at adjacent positions are equal, that is: S i (i ε )=S i+1 (i ε )=ε(θ ε ) S′ i (i ε )=S′ i+1 (i ε ) S″ i (i ε )=S″ i+1 (i ε ) The strain function S of each segment can be obtained by simultaneous solution i (θ), the strain function S(θ) is obtained by S i (θ) is a piecewise function.

9. The test method of the full-field deformation monitoring system for cylindrical shell structures under hydrostatic pressure according to claim 8 is characterized in that: The cylindrical shell has no section where strain sensors are arranged, and the strain function S of each group of strain sensor section positions is m (θ) is calculated based on the hoop strain function S(θ) of the cylindrical shell of this section: Among them, ξ m It is the reciprocal of the square of the axial distance between the section and each group of circumferential measuring points.

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