Deformation detection method for end plates

Abstract

The present invention relates to a deformation detection method for an end plate, comprising the following steps: providing an optical fiber, fixing the optical fiber to the surface of the end plate, and extending the optical fiber along the height direction of the end plate; establishing an XYZ coordinate system, with the Z axis extending along the extension direction of the optical fiber, and the X axis and the Y axis extending along the directions of two neutral axes perpendicular to the Z axis; dividing the optical fiber into a plurality of micro-segments of set lengths, the coordinates of the micro-segments being (x1, y1, z), measuring the strain of the end plate corresponding to each micro-segment using the optical fiber, and then calculating the deformation of the end plate based on the strain. The present invention effectively solves the problem of difficulty in detecting the deformation of large underwater components. The detection points are relatively dense and can be applied to large components. Moreover, this method can be applied to underwater construction environments and is not easily disturbed by environmental factors such as water flow, thereby improving the credibility of the detection results.

Description

Technical Field

[0001] The present invention relates to the field of underwater construction, and in particular to a deformation detection method for an end plate. Background Art

[0002] During underwater salvage operations, it is usually necessary to insert the end plate into the water bottom and fix it to provide a fixed foundation for the salvage equipment. During the construction process, the end plate often needs to withstand more complex stresses. Therefore, it is necessary to detect the force and deformation of the end plate to ensure the safety of construction. The currently commonly used deformation detection method is to install strain gauges and displacement gauges on the components. However, these two methods can only detect the fatigue-prone and damage-prone positions of the components, that is, they can only achieve single-point detection and are not suitable for large end plates. In addition, the end plate must be fixed to the bottom of the water. The strain gauges and displacement gauges have a low survival rate underwater and are easily interfered with by water flow, coatings and debris. The credibility of the detection results is not high. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects of the prior art and provide a deformation detection method for end plates, which solves the problem of difficulty in detecting the deformation of large underwater components. The detection points are relatively dense and can be applied to large components. This method can be applied to underwater construction environments and is not easily disturbed by environmental factors such as water flow, thereby improving the credibility of the detection results.

[0004] The technical solution to achieve the above purpose is:

[0005] The present invention provides a deformation detection method for an end plate, comprising the following steps:

[0006] Providing an optical fiber, fixing the optical fiber to the surface of the end plate, and extending the optical fiber along the height direction of the end plate;

[0007] An XYZ coordinate system is established, wherein the Z axis extends along the extension direction of the optical fiber, and the X axis and the Y axis extend along the directions of two neutral axes perpendicular to the Z axis respectively;

[0008] The optical fiber is divided into several micro-segments of set lengths, with the coordinates of the micro-segments being (x1, y1, z). The strain at each micro-segment of the end plate is measured using the optical fiber, and the deformation of the end plate at the micro-segment is calculated based on the strain.

[0009] The present invention proposes a deformation detection method for an end plate, which measures the strain at each micro-segment of the end plate by using optical fiber, and then calculates the deformation of the end plate based on the strain. Since the optical fiber extends along the surface of the end plate, the detection points are relatively dense, which can be applicable to deformation detection of large components. The optical fiber is less affected by external environmental factors, so the reliability of the detection results can be improved, solving the problem of difficulty in detecting the deformation of large underwater components. The detection points are relatively dense and can be applicable to large components. This method can be applied to underwater construction environments and is not easily disturbed by environmental factors such as water flow, thereby improving the credibility of the detection results.

[0010] A further improvement of the deformation detection method for the end plate of the present invention is that when calculating the deformation of the end plate, the optical fiber is divided into a plurality of micro segments of 0.001 m. The calculation formula is as follows:

[0011]

[0012]

[0013] Among them, θ Mx (z) is the angle change caused by the bending moment around the X axis at the Z position, ε i is the strain measured at the i-th micro-segment, y1 is the coordinate of the optical fiber on the Y axis, and C1 is the cross-sectional rotation angle θ at Z=0 on the Z axis. Mx (0), v is the deformation in the Y-axis direction, Z is the coordinate of the Z-axis at the Z position, θ Mx (z i ) is the angle change caused by the bending moment around the X axis at the i-th micro-segment, C2 is the cross-sectional rotation angle ω at Z = 0 on the Z axis Mx (0).

[0014] A further improvement of the deformation detection method for the end plate of the present invention is that it also includes three optical fibers spaced apart along the Z-axis direction of the end plate, and the coordinates of the three optical fibers are (x1, y1, z), (x2, y2, z) and (x3, y3, z), respectively. The first-order derivative of the angular change caused by the bending moment around the Y-axis at the Z position is calculated based on the strain measured by the three optical fibers. The first derivative of the angle change caused by the bending moment around the X axis at the Z position And the strain ε caused by the axial force in the Z axis at the Z position N (z), is calculated as follows:

[0015]

[0016] and The rank of is 3, so and ε N The only solution of (z), and then according to and ε N (z) Calculate the displacement changes in the X-axis, Y-axis and Z-axis directions;

[0017] Wherein, ε1(z) is the strain at the Z position measured by the optical fiber with coordinates (x1, y1, z), ε2(z) is the strain at the Z position measured by the optical fiber with coordinates (x2, y2, z), and ε3(z) is the strain at the Z position measured by the optical fiber with coordinates (x3, y3, z).

[0018] A further improvement of the deformation detection method for the end plate of the present invention is that when calculating the deformation of the end plate, each optical fiber is divided into a number of micro-segments of 0.001 m. The calculation formula is as follows:

[0019]

[0020] Where μ is the deformation in the X-axis direction, is the first derivative of the angle change caused by the bending moment around the Y axis at the Z position, θ My (z i ) is the angle change caused by the bending moment around the Y axis at the i-th micro-segment, C1 is the cross-sectional rotation angle θ at Z=0 on the Z axis My (0), C2 is the displacement in the X-axis direction at Z=0 and is equal to 0, and Z is the coordinate of the Z-axis at the Z position.

[0021] A further improvement of the deformation detection method for an end plate of the present invention is that it further comprises:

[0022]

[0023] Where v is the deformation in the Y-axis direction, is the first derivative of the angle change caused by the bending moment around the X axis at the Z position, θ Mx (z i ) is the angle change caused by the bending moment around the X axis at the i-th micro-segment, C3 is the cross-sectional rotation angle θ at Z=0 on the Z axis Mx (0), C4 is the displacement in the Y-axis direction at Z=0 and is taken as 0, and Z is the coordinate of the Z-axis at the Z position.

[0024] A further improvement of the deformation detection method for an end plate of the present invention is that it further comprises:

[0025]

[0026] Where w is the deformation in the Z-axis direction, ε N (z) is the strain caused by the axial force in the Z axis at the Z position, and C5 is the displacement caused by the Z axis tension at Z=0 on the Z axis and is taken as 0.

[0027] A further improvement of the deformation detection method for an end plate of the present invention is that an underwater construction device is installed on one side of the end plate, and when the optical fiber is provided, the method further comprises:

[0028] Two optical fibers parallel to each other are fixed on a side surface of the end plate away from the underwater construction device, and one optical fiber is fixed on a side surface of the end plate close to the underwater construction device.

[0029] A further improvement of the deformation detection method for an end plate of the present invention is that, when fixing the optical fiber, the method further comprises:

[0030] The optical fiber is glued and fixed to the surface of the end plate, and extends downward along the height direction of the end plate to the bottom of the end plate to form a first vertical section;

[0031] The optical fiber is bent and fixed to the surface of the end plate along the width direction of the end plate to form a horizontal section;

[0032] The optical fiber is bent and extended along the height direction of the end plate to the top of the end plate to form a second vertical section opposite to the first vertical section.

[0033] A further improvement of the deformation detection method for an end plate of the present invention is that the optical fiber is arranged near the middle of the end plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of the side of the end plate close to the underwater construction device in the deformation detection method for the end plate of the present invention.

[0035] Figure 2 It is a structural schematic diagram of the side of the end plate away from the underwater construction device in the deformation detection method for the end plate of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0037] The present invention provides a deformation detection method for an end plate. By using optical fiber to measure the strain at each micro-segment of the end plate, the deformation of the end plate can be calculated based on the strain. Since the optical fiber extends along the surface of the end plate, the detection points are relatively dense, which is applicable to deformation detection of large components. The optical fiber is less affected by external environmental factors, thereby improving the reliability of the detection results and solving the problem of difficulty in detecting the deformation of large underwater components. The relatively dense detection points are applicable to large components, and this method can be applied to underwater construction environments and is not easily disturbed by environmental factors such as water flow, thereby improving the credibility of the detection results. The deformation detection method for an end plate of the present invention is described below with reference to the accompanying drawings.

[0038] See Figure 1 , Figure 1This is a structural diagram of the side of the end plate close to the underwater construction device in the deformation detection method of the end plate of the present invention. Figure 1 , the deformation detection method for the end plate of the present invention is described.

[0039] like Figure 1 and Figure 2 As shown, the present invention provides a deformation detection method for an end plate, comprising the following steps:

[0040] Providing an optical fiber, fixing the optical fiber to the surface of the end plate, and extending the optical fiber along the height direction of the end plate;

[0041] An XYZ coordinate system is established, wherein the Z axis extends along the extension direction of the optical fiber, and the X axis and the Y axis extend along the directions of two neutral axes perpendicular to the Z axis respectively;

[0042] The optical fiber is divided into several micro-segments of set lengths, with the coordinates of the micro-segments being (x1, y1, z). The strain at each micro-segment of the end plate is measured using the optical fiber, and the deformation of the end plate at the micro-segment is calculated based on the strain.

[0043] Furthermore, an underwater construction device is installed on one side of the end plate 21, and when the optical fiber 11 is installed, the following is also included:

[0044] Two optical fibers 11 parallel to each other are fixed on a surface of the end plate 21 away from the underwater construction device, and one optical fiber 11 is fixed on a surface of the end plate 21 close to the underwater construction device.

[0045] Specifically, when fixing the optical fiber 11, the following steps are also included:

[0046] The optical fiber 11 is adhered and fixed to the surface of the end plate 21 and extends downward along the height direction of the end plate 21 to the bottom of the end plate to form a first vertical section;

[0047] The optical fiber 11 is bent and fixed to the surface of the end plate 21 along the width direction of the end plate 21 to form a horizontal section;

[0048] The optical fiber 11 is bent and extended along the height direction of the end plate 21 to the top of the end plate 21 to form a second vertical section opposite to the first vertical section.

[0049] Preferably, the optical fiber 11 is disposed near the middle of the end plate 21 .

[0050] As a preferred embodiment of the present invention, when calculating the deformation of the end plate, the optical fiber is divided into a number of 0.001m micro-segments. The calculation formula is as follows:

[0051]

[0052] Among them, θ Mx(z) is the angle change caused by the bending moment around the X axis at the Z position, ε i is the strain measured at the i-th micro-segment, y1 is the coordinate of the optical fiber on the Y axis, and C1 is the cross-sectional rotation angle θ at Z=0 on the Z axis. Mx (0), v is the deformation in the Y-axis direction, Z is the coordinate of the Z-axis at the Z position, θ Mx (z i ) is the angle change caused by the bending moment around the X axis at the i-th micro-segment, C2 is the cross-sectional rotation angle ω at Z = 0 on the Z axis Mx The value of (0)

[0053] As a preferred embodiment of the present invention, three optical fibers are arranged at intervals along the Z-axis direction of the end plate, and the coordinates of the three optical fibers are (x1, y1, z), (x2, y2, z) and (x3, y3, z), respectively. The first-order derivative of the angular change caused by the bending moment around the Y-axis at the Z position is calculated based on the strain measured by the three optical fibers. The first derivative of the angle change caused by the bending moment around the X axis at the Z position And the strain ε caused by the axial force in the Z axis at the Z position N (z), is calculated as follows:

[0054]

[0055] and The rank of is 3, so and ε N The only solution of (z), and then according to and ε N (z) Calculate the displacement changes in the X-axis, Y-axis and Z-axis directions;

[0056] Wherein, ε1(z) is the strain at the Z position measured by the optical fiber with coordinates (x1, y1, z), ε2(z) is the strain at the Z position measured by the optical fiber with coordinates (x2, y2, z), and ε3(z) is the strain at the Z position measured by the optical fiber with coordinates (x3, y3, z).

[0057] Furthermore, when calculating the deformation of the end plate, each optical fiber is divided into several 0.001m micro-segments. The calculation formula is as follows:

[0058]

[0059] Where μ is the deformation in the X-axis direction, is the first derivative of the angle change caused by the bending moment around the Y axis at the Z position, θ My (z i ) is the angle change caused by the bending moment around the Y axis at the i-th micro-segment, C1 is the cross-sectional rotation angle θ at Z=0 on the Z axisMy (0), C2 is the displacement in the X-axis direction at Z=0 and is equal to 0, and Z is the coordinate of the Z-axis at the Z position.

[0060] Specifically, it also includes:

[0061]

[0062] Where v is the deformation in the Y-axis direction, is the first derivative of the angle change caused by the bending moment around the X axis at the Z position, θ Mx (z i ) is the angle change caused by the bending moment around the X axis at the i-th micro-segment, C3 is the cross-sectional rotation angle θ at Z=0 on the Z axis Mx (0), C4 is the displacement in the Y-axis direction at Z=0 and is taken as 0, and Z is the coordinate of the Z-axis at the Z position.

[0063] Specifically, it also includes:

[0064]

[0065] Where w is the deformation in the Z-axis direction, ε N (z) is the strain caused by the axial force in the Z axis at the Z position, and C5 is the displacement caused by the Z axis tension at Z=0 on the Z axis and is taken as 0.

[0066] The specific implementation of the present invention is as follows:

[0067] Two optical fibers 11 parallel to each other are fixed on a surface of the end plate 21 away from the underwater construction device, and one optical fiber 11 is fixed on a surface of the end plate 21 close to the underwater construction device.

[0068] When it is assumed that deformation occurs only in the Z0Y plane, the coordinates of an optical fiber are defined as (x1, y1, z), and the optical fiber is divided into several micro-segments of 0.001 m. The calculation formula is as follows:

[0069]

[0070] Among them, θ Mx (z) is the angle change caused by the bending moment around the X axis at the Z position, ε i is the strain measured at the i-th micro-segment, y1 is the coordinate of the optical fiber on the Y axis, and C1 is the cross-sectional rotation angle θ at Z=0 on the Z axis. Mx (0), v is the deformation in the Y-axis direction, Z is the coordinate of the Z-axis at the Z position, θ Mx (z i ) is the angle change caused by the bending moment around the X axis at the i-th micro-segment, C2 is the cross-sectional rotation angle ω at Z = 0 on the Z axis Mx (0) value;

[0071] That is, the angular deformation of the corresponding position is calculated based on the strain measured at the i-th micro-segment, and then the angular deformation of each micro-segment is substituted into the calculation formula of v to calculate the deformation in the Y-axis direction.

[0072] When the two planes Z0Y and X0Z are considered to be bent and tensile, the coordinates of the three optical fibers are marked as (x1, y1, z), (x2, y2, z), and (x3, y3, z). The first-order derivative of the angular change caused by the bending moment around the Y axis at the Z position is calculated based on the strain measured on the three optical fibers. The first derivative of the angle change caused by the bending moment around the X axis at the Z position And the strain ε caused by the axial force in the Z axis at the Z position N (z), is calculated as follows:

[0073]

[0074] and The rank of is 3, so and ε N The only solution of (z), and then according to and ε N (z) Calculate the displacement changes in the X-axis, Y-axis and Z-axis directions;

[0075] Wherein, ε1(z) is the strain at the Z position measured by the optical fiber with coordinates (x1, y1, z), ε2(z) is the strain at the Z position measured by the optical fiber with coordinates (x2, y2, z), and ε3(z) is the strain at the Z position measured by the optical fiber with coordinates (x3, y3, z);

[0076] Each optical fiber is divided into several 0.001m micro-segments. The calculation formula is as follows:

[0077]

[0078] Where μ is the deformation in the X-axis direction, is the first derivative of the angle change caused by the bending moment around the Y axis at the Z position, θ My (z i ) is the angle change caused by the bending moment around the Y axis at the i-th micro-segment, C1 is the cross-sectional rotation angle θ at Z=0 on the Z axis My (0), C2 is the displacement in the X-axis direction at Z = 0 and is taken as 0, and Z is the coordinate of the Z-axis at the Z position;

[0079] That is, for the obtained By performing two integrations, the deformation in the X-axis direction can be calculated;

[0080]

[0081] Where v is the deformation in the Y-axis direction, is the first derivative of the angle change caused by the bending moment around the X axis at the Z position, θ Mx (z i ) is the angle change caused by the bending moment around the X axis at the i-th micro-segment, C3 is the cross-sectional rotation angle θ at Z=0 on the Z axis Mx (0), C4 is the displacement in the Y-axis direction at Z = 0 and takes 0, and Z is the coordinate of the Z-axis at the Z position;

[0082] That is, for the obtained By performing two integrations, the deformation in the Y-axis direction can be calculated;

[0083]

[0084] Where w is the deformation in the Z-axis direction, ε N (z) is the strain caused by the axial force in the Z axis at the Z position, C5 is the displacement caused by the Z axis tension at Z = 0 and is taken as 0;

[0085] That is, for the obtained ε N (z) is integrated to calculate the deformation in the Z-axis direction;

[0086] In summary, the deformation of the end plate along the X-axis, Y-axis and Z-axis can be obtained.

[0087] The present invention has been described in detail above with reference to the embodiments of the accompanying drawings. A person skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details in the embodiments should not be construed as limiting the present invention. The scope of protection of the present invention shall be determined by the scope defined in the appended claims.

Claims

1. A method for detecting deformation of an end plate, characterized in that: The steps include: Providing an optical fiber, fixing the optical fiber to the surface of the end plate, and extending along the height direction of the end plate; Establishing an XYZ coordinate system, wherein the Z axis extends along the extension direction of the optical fiber, and the X axis and the Y axis extend along the directions of two neutral axes perpendicular to the Z axis respectively; The optical fiber is divided into a plurality of micro-segments of set lengths, wherein the coordinates of the micro-segments are (x1, y1, z), and the strain of the end plate corresponding to each micro-segment is measured using the optical fiber, and then the deformation of the end plate corresponding to the micro-segment is calculated based on the strain; It also includes three optical fibers spaced apart along the Z-axis direction of the end plate, wherein the coordinates of the three optical fibers are (x1, y1, z), (x2, y2, z) and (x3, y3, z), respectively, and the first-order derivative of the angular change caused by the bending moment around the Y-axis at the Z position is calculated based on the strain measured by the three optical fibers. The first derivative of the angle change caused by the bending moment around the X axis at the Z position And the strain ε caused by the axial force in the Z axis at the Z position N (z), is calculated as follows: and The rank of is 3, so and ε N The only solution of (z), and then according to and ε N (z) Calculate the displacement changes in the X-axis, Y-axis and Z-axis directions; Wherein, ε1(z) is the strain at the Z position measured by the optical fiber with coordinates (x1, y1, z), ε2(z) is the strain at the Z position measured by the optical fiber with coordinates (x2, y2, z), and ε3(z) is the strain at the Z position measured by the optical fiber with coordinates (x3, y3, z).

2. The deformation detection method for an end plate according to claim 1, characterized in that: When calculating the deformation of the end plate, the optical fiber is also divided into several 0.001 m micro segments. The calculation formula is as follows: Among them, θ Mx (z) is the angle change caused by the bending moment around the X axis at the Z position, ε i is the strain measured at the i-th micro-segment, y1 is the coordinate of the optical fiber on the Y axis, and C1 is the cross-sectional rotation angle θ at Z=0 on the Z axis. Mx (0), v is the deformation in the Y-axis direction, Z is the coordinate of the Z-axis at the Z position, θ Mx (z i ) is the angle change caused by the bending moment around the X axis at the i-th micro-segment, C2 is the cross-sectional rotation angle ω at Z = 0 on the Z axis Mx (0).

3. The deformation detection method for an end plate according to claim 1, characterized in that: When calculating the deformation of the end plate, each optical fiber is divided into a number of 0.001 m micro segments. The calculation formula is as follows: Where μ is the deformation in the X-axis direction, is the first derivative of the angle change caused by the bending moment around the Y axis at the Z position, θ My (z i ) is the angle change caused by the bending moment around the Y axis at the i-th micro-segment, C1 is the cross-sectional rotation angle θ at Z=0 on the Z axis My (0), C2 is the displacement in the X-axis direction at Z=0 and is equal to 0, and Z is the coordinate of the Z-axis at the Z position.

4. The deformation detection method for an end plate according to claim 3, characterized in that: Also includes: Where v is the deformation in the Y-axis direction, is the first derivative of the angle change caused by the bending moment around the X axis at the Z position, θ Mx (z i ) is the angle change caused by the bending moment around the X axis at the i-th micro-segment, C3 is the cross-sectional rotation angle θ at Z=0 on the Z axis Mx (0), C4 is the displacement in the Y-axis direction at Z=0 and is taken as 0, and Z is the coordinate of the Z-axis at the Z position.

5. The deformation detection method for an end plate according to claim 4, characterized in that: Also includes: Where w is the deformation in the Z-axis direction, ε N (z) is the strain caused by the axial force in the Z axis at the Z position, and C5 is the displacement caused by the Z axis tension at Z=0 on the Z axis and is taken as 0.

6. The deformation detection method for an end plate according to claim 1, characterized in that: An underwater construction device is installed on one side of the end plate, and when the optical fiber is installed, the following is also included: Two optical fibers parallel to each other are fixed on a side surface of the end plate away from the underwater construction device, and one optical fiber is fixed on a side surface of the end plate close to the underwater construction device.

7. The deformation detection method for an end plate according to claim 6, characterized in that: When fixing the optical fiber, the method further comprises: Adhere and fix the optical fiber to the surface of the end plate, and extend the optical fiber downward along the height direction of the end plate to the bottom of the end plate to form a first vertical section; Bending the optical fiber and adhering and fixing it to the surface of the end plate along the width direction of the end plate to form a horizontal section; The optical fiber is bent and extended along the height direction of the end plate to the top of the end plate to form a second vertical section opposite to the first vertical section.

8. The deformation detection method for an end plate according to claim 1, characterized in that: The optical fiber is arranged near the middle of the end plate.

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