Deformation detection method for curved beams

Abstract

The present invention relates to a deformation detection method for a curved beam, comprising the following steps: providing optical fibers, fixing three optical fibers to the surface of the curved beam and extending along the axis of the curved beam; establishing an XYZ coordinate system, which is a moving coordinate system that changes along the axis of the curved beam, with the Z axis extending in the tangent direction of the axis of the curved beam; establishing a static UVW coordinate system with one end of the curved beam as the origin; using optical fibers to measure the strain at each micro-segment of the curved beam, and then calculating the deformation of the curved beam based on the strain and the angle between the Z axis at the corresponding micro-segment and the UOW plane and the VOW plane. The present invention effectively solves the problem of difficult deformation detection of large underwater curved components. The detection points are relatively dense and can be applied to large curved components. This method can also be applied to underwater construction environments and is not easily affected 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 a curved beam. Background Art

[0002] During underwater salvage operations, curved beams need to be drilled into the water bottom. During the construction process, curved beams often need to withstand relatively complex stresses. Therefore, the force and deformation of the curved beams need to be tested to ensure the safety of construction. The commonly used deformation detection method is to install strain gauges and displacement meters on the components. However, these two methods can only detect the fatigue-prone and damage-prone parts of the components, that is, they can only achieve single-point detection and are not suitable for large and curved curved beams. In addition, curved beams need to be drilled into the water bottom, and strain gauges and displacement meters have a low survival rate underwater and are easily interfered 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 curved beams, which solves the problem of difficulty in detecting the deformation of large underwater curved components. The detection points are relatively dense and can be applied to large curved 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 a curved beam, comprising the following steps:

[0006] Providing optical fibers, fixing three optical fibers on the surface of the curved beam and extending along the axis of the curved beam, the three optical fibers being respectively arranged on two opposite sides of the curved beam;

[0007] Establishing an XYZ coordinate system, which is a motion coordinate system that changes along the axis of the curved beam, wherein the Z axis extends in a tangential direction of the axis of the curved beam, and the X axis and the Y axis extend in directions of two neutral axes perpendicular to the Z axis;

[0008] A static UVW coordinate system is established with one end of the curved beam as the origin, and the extension directions of the U axis, V axis, and W axis are respectively consistent with the extension directions of the X axis, Y axis, and Z axis of one end of the curved beam;

[0009] Each optical fiber is divided into several micro-segments of set lengths. The coordinates of the micro-segments of the three optical fibers are (x1, y1, z), (x2, y2, z), and (x3, y3, z), respectively. The strain of the curved beam corresponding to each micro-segment is measured using optical fibers. The deformation of the curved beam is then calculated based on the strain and the angles between the Z axis at the corresponding micro-segment and the UOW plane and the VOW plane, specifically:

[0010] The first derivative of the angle 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:

[0011]

[0012] and The rank of is 3, so and ε N The only solution of (z) and Integrate to get θ My (z) and θ Mx (z), according to θ My (z),θ Mx (z) and ε N (z) and the angles between the Z axis and the UOW plane and the VOW plane at the corresponding micro-segment to calculate the deformation of the curved beam;

[0013] Where, 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), ε3(z) is the strain at the Z position measured by the optical fiber with coordinates (x3, y3, z), and θ My (z) is the angle change caused by the bending moment around the Y axis at the Z position, θ Mx (z) is the angular change caused by the bending moment around the X axis at the Z position;

[0014] Then θ Mx (z),θ My (z) and ε N (z) Decompose along the V-axis, U-axis, and W-axis respectively to obtain the corresponding deformation, which is then summed up to obtain the total deformation in the U-axis, V-axis, and W-axis directions, thereby characterizing the deformation of the curved beam.

[0015] The present invention proposes a deformation detection method for a curved beam. The method calculates the angular variation caused by the bending moments around the X-axis and the Y-axis and the strain caused by the Z-axis axial force based on the strain of each micro-segment, and then decomposes them along the V-axis, U-axis and W-axis to obtain corresponding deformations, which are then summed to obtain the total deformations in the U-axis, V-axis and W-axis directions, thereby characterizing the deformation of the curved beam. Since optical fiber is less affected by the environment, it can be applied to underwater construction environments, solving the problem of difficulty in detecting the deformation of large underwater curved components. The relatively dense detection points can be applied to large curved 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.

[0016] A further improvement of the deformation detection method for curved beams of the present invention is that it further includes the following steps: Mx The deformation caused by (z) is decomposed along the V-axis and W-axis directions, and the specific formula is as follows:

[0017]

[0018] Among them, dv Mx is the displacement change in the V-axis direction caused by the bending moment around the X-axis, θ Mx (z) is the angle change caused by the bending moment around the X axis at the Z position, is the angle between the Z axis and the UOW plane at the Z position, dw Mx is the displacement change in the W-axis direction caused by the bending moment around the X-axis, dz is the length of the micro-segment and is taken as 0.001m.

[0019] A further improvement of the deformation detection method for curved beams of the present invention is that it further includes the following steps: My The deformation caused by (z) is decomposed along the U-axis and W-axis directions, and the specific formula is as follows:

[0020]

[0021] Among them, dμ My is the displacement change in the U-axis direction caused by the bending moment around the Y-axis, θ My (z) is the angle change caused by the bending moment around the Y axis at the Z position, is the angle between the Z axis and the VOW plane at the Z position, dw My is the displacement change in the W-axis direction caused by the bending moment around the Y-axis, dz is the length of the micro-segment and is taken as 0.001m.

[0022] A further improvement of the deformation detection method for curved beams of the present invention is that the method further includes converting ε N The deformation caused by (z) is decomposed along the V-axis direction, and the specific formula is as follows:

[0023]

[0024] Among them, dv N is the displacement change in the V-axis direction caused by the axial force in the Z-axis direction, ε N (z) is the strain caused by the axial force in the Z direction at the Z position, is the angle between the Z axis and the UOW plane at the Z position, dz is the length of the micro segment and is taken as 0.001m.

[0025] A further improvement of the deformation detection method for curved beams of the present invention is that the method further includes converting ε N The deformation caused by (z) is decomposed along the U axis, and the specific formula is as follows:

[0026]

[0027] Among them, dμ N is the displacement change in the U-axis direction caused by the axial force in the Z-axis direction, ε N (z) is the strain caused by the axial force in the Z direction at the Z position, is the angle between the Z axis and the VOW plane at the Z position, dz is the length of the micro segment and is taken as 0.001m.

[0028] A further improvement of the deformation detection method for curved beams of the present invention is that the method further includes converting ε N The deformation caused by (z) is decomposed along the W axis, and the specific formula is as follows:

[0029]

[0030] Among them, dw N is the displacement change in the W-axis direction caused by the axial force in the Z-axis direction, ε N (z) is the strain caused by the axial force in the Z direction at the Z position, is the angle between the Z axis and the UOW plane at the Z position, is the angle between the Z axis and the VOW plane at the Z position, is the angle between the Z axis and the UOV plane at the Z position, dz is the length of the micro segment and is taken as 0.001m.

[0031] A further improvement of the deformation detection method for a curved beam of the present invention is that it further includes calculating the total deformation in the U-axis direction. The specific formula is as follows:

[0032]

[0033] Among them, μ is the total deformation in the U-axis direction, dμ My is the displacement change in the U-axis direction caused by the bending moment around the Y-axis, dμ Nis the displacement change in the U-axis direction caused by the axial force in the Z-axis direction, and 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 set to 0, θ My (z i ) is the angle change caused by the bending moment around the Y axis at the i-th micro-segment, is the angle between the Z axis and the VOW plane at the Z position, ε i N (z) is the strain caused by the axial force in the Z axis at the i-th micro segment, L is the distance between the Z position and the origin of the UVW coordinate, is the angle between the Z axis and the VOW plane at the Z=0 position.

[0034] A further improvement of the deformation detection method for a curved beam of the present invention is that it also includes calculating the total deformation in the V-axis direction. The specific formula is as follows:

[0035]

[0036] Where ν is the total deformation in the V-axis direction, dν Mx is the displacement change in the V-axis direction caused by the bending moment around the X-axis, dv N is the displacement change in the V-axis direction caused by the axial force in the Z-axis direction, C4 is the displacement in the Y-axis direction at Z=0 and is taken as 0, θ Mx (z i ) is the angle change caused by the bending moment around the X axis at the i-th micro-segment, is the angle between the Z axis and the UOW plane at the Z position, ε i N (z) is the strain caused by the axial force in the Z-axis direction at the i-th micro-segment, and C3 is the cross-sectional rotation angle θ at the Z-axis Z=0. Mx (0), is the angle between the Z axis and the UOW plane at the Z=0 position, and L is the distance between the Z position and the origin of the UVW coordinate system.

[0037] A further improvement of the deformation detection method for a curved beam of the present invention is that it further includes calculating the total deformation in the W-axis direction. The specific formula is as follows:

[0038]

[0039]

[0040] Where w is the total deformation in the W-axis direction, dw Mx is the displacement change in the W-axis direction caused by the bending moment around the X-axis, dw My is the displacement change in the W-axis direction caused by the bending moment around the Y-axis, dw Nis the displacement change in the W-axis direction caused by the axial force in the Z-axis direction, C5 is the displacement caused by the Z-axis tension at Z=0 and is taken as 0, θ Mx (z i ) is the angle change caused by the bending moment around the X axis at the i-th micro-segment, is the angle between the Z axis and the UOW plane 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, is the angle between the Z axis and the VOW plane at the Z position, ε i N (z) is the strain caused by the axial force in the Z axis at the i-th micro segment, is the angle between the Z axis and the UOV plane at the Z position, and C1 is the cross-sectional rotation angle θ at the Z axis Z = 0 My (0), is the angle between the Z axis and the VOW plane at Z = 0, and C3 is the cross-sectional rotation angle θ at Z = 0. Mx (0), is the angle between the Z axis and the UOW plane at the Z=0 position, and L is the distance between the Z position and the origin of the UVW coordinate system. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a top view of the curved beam used in the deformation detection method of the curved beam according to the present invention.

[0042] Figure 2 It is a front view of the curved beam used in the deformation detection method of the curved beam according to the present invention. DETAILED DESCRIPTION

[0043] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0044] The present invention provides a deformation detection method for a curved beam. By calculating the angular variation caused by the bending moment around the X-axis and the Y-axis and the strain caused by the axial force along the Z-axis based on the strain of each micro-segment, these are then decomposed along the V-axis, U-axis, and W-axis to obtain the corresponding deformations, which are then summed to obtain the total deformations in the U-axis, V-axis, and W-axis directions. This method can characterize the deformation of the curved beam. Since optical fibers are less affected by the environment, they can be applied to underwater construction environments, solving the problem of difficulty in detecting the deformation of large underwater curved components. The relatively dense detection points make it applicable to large curved components. This method is applicable to underwater construction environments and is not easily interfered with by environmental factors such as water flow, thereby improving the credibility of the detection results. The following is an illustration of the deformation detection method for a curved beam according to the present invention, with reference to the accompanying drawings.

[0045] See Figure 1 , Figure 1 FIG. 1 is a top view of the arc beam in the deformation detection method for the arc beam of the present invention. Figure 1 , the deformation detection method for curved beams of the present invention is described.

[0046] like Figure 1 and Figure 2 As shown, the present invention provides a deformation detection method for a curved beam, comprising the following steps:

[0047] Providing optical fibers 11, fixing three optical fibers 11 on the surface of the curved beam 21 and extending along the axis of the curved beam 21, and respectively arranged on two opposite sides of the curved beam 21;

[0048] Establish an XYZ coordinate system, which is a motion coordinate system that changes along the axis of the curved beam 21, with the Z axis extending in a tangential direction of the axis of the curved beam 21, and the X axis and the Y axis extending in directions of two neutral axes perpendicular to the Z axis respectively;

[0049] A static UVW coordinate system is established with one end of the curved beam as the origin, and the extension directions of the U axis, V axis, and W axis are respectively consistent with the extension directions of the X axis, Y axis, and Z axis of one end of the curved beam;

[0050] Each optical fiber is divided into several micro-segments of set lengths. The coordinates of the micro-segments of the three optical fibers are (x1, y1, z), (x2, y2, z), and (x3, y3, z), respectively. The strain of the curved beam corresponding to each micro-segment is measured using optical fibers. The deformation of the curved beam is then calculated based on the strain and the angles between the Z axis at the corresponding micro-segment and the UOW plane and the VOW plane, specifically:

[0051] The first derivative of the angle 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:

[0052]

[0053] and The rank of is 3, so and ε N The only solution of (z) and Integrate to get θ My (z) and θ Mx (z), according to θ My (z),θ Mx (z) and εN (z) and the angles between the Z axis and the UOW plane and the VOW plane at the corresponding micro-segment to calculate the deformation of the curved beam;

[0054] Where, 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), ε3(z) is the strain at the Z position measured by the optical fiber with coordinates (x3, y3, z), and θ My (z) is the angle change caused by the bending moment around the Y axis at the Z position, θ Mx (z) is the angular change caused by the bending moment around the X axis at the Z position;

[0055] Then θ Mx (z),θ My (z) and ε N (z) Decompose along the V-axis, U-axis, and W-axis respectively to obtain the corresponding deformation, which is then summed up to obtain the total deformation in the U-axis, V-axis, and W-axis directions, thereby characterizing the deformation of the curved beam.

[0056] Specifically, two optical fibers 11 are adhered to two opposite side surfaces of the curved beam 21 , and the optical fibers 11 extend along the axis of the curved beam 21 .

[0057] Furthermore, it also includes the Mx The deformation caused by (z) is decomposed along the V-axis and W-axis directions, and the specific formula is as follows:

[0058]

[0059] Among them, dν Mx is the displacement change in the V-axis direction caused by the bending moment around the X-axis, θ Mx (z) is the angle change caused by the bending moment around the X axis at the Z position, is the angle between the Z axis and the UOW plane at the Z position, dw Mx is the displacement change in the W-axis direction caused by the bending moment around the X-axis, dz is the length of the micro-segment and is taken as 0.001m.

[0060] Specifically, it also includes the My The deformation caused by (z) is decomposed along the U-axis and W-axis directions, and the specific formula is as follows:

[0061]

[0062] Among them, dμ My is the displacement change in the U-axis direction caused by the bending moment around the Y-axis, θ My (z) is the angle change caused by the bending moment around the Y axis at the Z position, is the angle between the Z axis and the VOW plane at the Z position, dw My is the displacement change in the W-axis direction caused by the bending moment around the Y-axis, dz is the length of the micro-segment and is taken as 0.001m.

[0063] Specifically, it also includes the N The deformation caused by (z) is decomposed along the V-axis direction, and the specific formula is as follows:

[0064]

[0065] Among them, dν N is the displacement change in the V-axis direction caused by the axial force in the Z-axis direction, ε N (z) is the strain caused by the axial force in the Z direction at the Z position, is the angle between the Z axis and the UOW plane at the Z position, dz is the length of the micro segment and is taken as 0.001m.

[0066] Specifically, it also includes the N The deformation caused by (z) is decomposed along the U axis, and the specific formula is as follows:

[0067]

[0068] Among them, dμ N is the displacement change in the U-axis direction caused by the axial force in the Z-axis direction, ε N (z) is the strain caused by the axial force in the Z direction at the Z position, is the angle between the Z axis and the VOW plane at the Z position, dz is the length of the micro segment and is taken as 0.001m.

[0069] Specifically, it also includes the N The deformation caused by (z) is decomposed along the W axis, and the specific formula is as follows:

[0070]

[0071] Among them, dw N is the displacement change in the W-axis direction caused by the axial force in the Z-axis direction, ε N (z) is the strain caused by the axial force in the Z direction at the Z position, is the angle between the Z axis and the UOW plane at the Z position, is the angle between the Z axis and the VOW plane at the Z position, is the angle between the Z axis and the UOV plane at the Z position, dz is the length of the micro segment and is taken as 0.001m.

[0072] Furthermore, the total deformation in the U-axis direction is calculated. The specific formula is as follows:

[0073]

[0074] Among them, μ is the total deformation in the U-axis direction, dμ My is the displacement change in the U-axis direction caused by the bending moment around the Y-axis, dμ N is the displacement change in the U-axis direction caused by the axial force in the Z-axis direction, and 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 set to 0, θ My (z i ) is the angle change caused by the bending moment around the Y axis at the i-th micro-segment, is the angle between the Z axis and the VOW plane at the Z position, ε i N (z) is the strain caused by the axial force in the Z axis at the i-th micro segment, L is the distance between the Z position and the origin of the UVW coordinate, is the angle between the Z axis and the VOW plane at the Z=0 position.

[0075] Furthermore, the total deformation in the V-axis direction is calculated. The specific formula is as follows:

[0076]

[0077] Where v is the total deformation in the V-axis direction, dv Mx is the displacement change in the V-axis direction caused by the bending moment around the X-axis, dv N is the displacement change in the V-axis direction caused by the axial force in the Z-axis direction, C4 is the displacement in the Y-axis direction at Z=0 and is taken as 0, θ Mx (z i ) is the angle change caused by the bending moment around the X axis at the i-th micro-segment, is the angle between the Z axis and the UOW plane at the Z position, ε i N (z) is the strain caused by the axial force in the Z-axis direction at the i-th micro-segment, and C3 is the cross-sectional rotation angle θ at the Z-axis Z=0. Mx (0), is the angle between the Z axis and the UOW plane at the Z=0 position, and L is the distance between the Z position and the origin of the UVW coordinate system.

[0078] Furthermore, the total deformation in the W-axis direction is calculated. The specific formula is as follows:

[0079]

[0080] Where w is the total deformation in the W-axis direction, dw Mx is the displacement change in the W-axis direction caused by the bending moment around the X-axis, dw Myis the displacement change in the W-axis direction caused by the bending moment around the Y-axis, dw N is the displacement change in the W-axis direction caused by the axial force in the Z-axis direction, C5 is the displacement caused by the Z-axis tension at Z=0 and is taken as 0, θ Mx (z i ) is the angle change caused by the bending moment around the X axis at the i-th micro-segment, is the angle between the Z axis and the UOW plane 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, is the angle between the Z axis and the VOW plane at the Z position, ε i N (z) is the strain caused by the axial force in the Z axis at the i-th micro segment, is the angle between the Z axis and the UOV plane at the Z position, and C1 is the cross-sectional rotation angle θ at the Z axis Z = 0 My (0), is the angle between the Z axis and the VOW plane at Z = 0, and C3 is the cross-sectional rotation angle θ at Z = 0. Mx (0), is the angle between the Z axis and the UOW plane at the Z=0 position, and L is the distance between the Z position and the origin of the UVW coordinate system.

[0081] The specific implementation of the present invention is as follows:

[0082] An optical fiber 11 is fixed on the surface of the curved beam 21 and extends along the axis of the curved beam 21. Three optical fibers 11 can be provided, and the three optical fibers 11 are respectively provided on two opposite sides of the curved beam 21.

[0083] Establish an XYZ coordinate system, where the XYZ coordinate axis is a motion coordinate system that changes along the axis of the curved beam, and the Z axis extends in a tangential direction of the axis of the curved beam, and the X axis and the Y axis extend in directions of two neutral axes perpendicular to the Z axis respectively;

[0084] A static UVW coordinate system is established with one end of the curved beam as the origin, and the extension directions of the U axis, V axis, and W axis are respectively consistent with the extension directions of the X axis, Y axis, and Z axis of one end of the curved beam;

[0085] Each optical fiber is divided into several micro-segments of set lengths. The coordinates of the micro-segments 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 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 positionN (z), is calculated as follows:

[0086]

[0087] and The rank of is 3, so and ε N The only solution of (z) and Integrate to get θ My (z) and θ Mx (z), according to θ My (z),θ Mx (z) and ε N (z) and the angles between the Z axis and the UOW plane and the VOW plane at the corresponding micro-segment to calculate the deformation of the curved beam;

[0088] will be represented by θ Mx The deformation caused by (z) is decomposed along the V-axis and W-axis directions, and the specific formula is as follows:

[0089]

[0090] will be represented by θ My The deformation caused by (z) is decomposed along the U-axis and W-axis directions, and the specific formula is as follows:

[0091]

[0092] Will be N The deformation caused by (z) is decomposed along the V-axis direction, and the specific formula is as follows:

[0093]

[0094] Will be N The deformation caused by (z) is decomposed along the U axis, and the specific formula is as follows:

[0095]

[0096] Will be N The deformation caused by (z) is decomposed along the W axis, and the specific formula is as follows:

[0097]

[0098] in, It can be obtained through testing or and Calculated Then substitute the values ​​of the variables obtained above into the formulas below;

[0099] Calculate the total deformation in the U-axis direction. The specific formula is as follows:

[0100]

[0101] Calculate the total deformation in the V-axis direction. The specific formula is as follows:

[0102]

[0103] Calculate the total deformation in the W-axis direction. The specific formula is as follows:

[0104]

[0105] In summary, the total deformation in the three directions of U-axis, V-axis and W-axis was calculated, which can characterize the deformation of the curved beam and provide guidance for construction.

[0106] 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 deformation detection method for a curved beam, characterized in that: The steps include: Providing optical fibers, fixing three of the optical fibers on the surface of the curved beam and extending along the axis of the curved beam, the three optical fibers being respectively arranged on two opposite sides of the curved beam; Establishing an XYZ coordinate system, wherein the XYZ coordinate system is a motion coordinate system that changes along the axis of the curved beam, wherein the Z axis extends in a tangential direction of the axis of the curved beam, and the X axis and the Y axis extend in directions of two neutral axes perpendicular to the Z axis; Establishing a static UVW coordinate system with one end of the curved beam as the origin, wherein the extension directions of the U axis, V axis, and W axis are respectively consistent with the extension directions of the X axis, Y axis, and Z axis of one end of the curved beam; Each optical fiber is divided into several micro-segments of set lengths, and the coordinates of the micro-segments of the three optical fibers are respectively (x1, y1, z), (x2, y2, z) and (x3, y3, z). The strain of the arc beam corresponding to each micro-segment is measured using the optical fiber, and then the deformation of the arc beam is calculated based on the strain and the angle between the Z axis of the corresponding micro-segment and the UOW plane and the VOW plane, specifically including: calculating the first-order derivative of the angle change caused by the bending moment around the Y axis at the Z position 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 Integrate to get θ My (z) and θ Mx (z), according to θ My (z),θ Mx (z) and ε N (z) and the angles between the Z axis at the corresponding micro-segment and the UOW plane and the VOW plane to calculate the deformation of the curved beam; Where, 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), ε3(z) is the strain at the Z position measured by the optical fiber with coordinates (x3, y3, z), and θ My (z) is the angle change caused by the bending moment around the Y axis at the Z position, θ Mx (z) is the angular change caused by the bending moment around the X axis at the Z position; Then θ Mx (z),θ My (z) and ε N (z) Decompose along the V-axis, U-axis, and W-axis respectively to obtain the corresponding deformation, which is then summed up to obtain the total deformation in the U-axis, V-axis, and W-axis directions, thereby characterizing the deformation of the curved beam.

2. The deformation detection method for a curved beam according to claim 1, wherein: It also includes the Mx The deformation caused by (z) is decomposed along the V-axis and W-axis directions, and the specific formula is as follows: Among them, dv Mx is the displacement change in the V-axis direction caused by the bending moment around the X-axis, θ Mx (z) is the angle change caused by the bending moment around the X axis at the Z position, is the angle between the Z axis and the UOW plane at the Z position, dw Mx is the displacement change in the W-axis direction caused by the bending moment around the X-axis, dz is the length of the micro-segment and is taken as 0.001m.

3. The deformation detection method for a curved beam according to claim 2, characterized in that: It also includes the My The deformation caused by (z) is decomposed along the U-axis and W-axis directions, and the specific formula is as follows: Among them, dμ My is the displacement change in the U-axis direction caused by the bending moment around the Y-axis, θ My (z) is the angle change caused by the bending moment around the Y axis at the Z position, is the angle between the Z axis and the VOW plane at the Z position, dw My is the displacement change in the W-axis direction caused by the bending moment around the Y-axis, dz is the length of the micro-segment and is taken as 0.001m.

4. The deformation detection method for a curved beam according to claim 3, wherein: Also included is the N The deformation caused by (z) is decomposed along the V-axis direction, and the specific formula is as follows: Among them, dv N is the displacement change in the V-axis direction caused by the axial force in the Z-axis direction, ε N (z) is the strain caused by the axial force in the Z direction at the Z position, is the angle between the Z axis and the UOW plane at the Z position, dz is the length of the micro segment and is taken as 0.001m.

5. The deformation detection method for a curved beam according to claim 4, characterized in that: Also included is the N The deformation caused by (z) is decomposed along the U axis, and the specific formula is as follows: Among them, dμ N is the displacement change in the U-axis direction caused by the axial force in the Z-axis direction, ε N (z) is the strain caused by the axial force in the Z direction at the Z position, is the angle between the Z axis and the VOW plane at the Z position, dz is the length of the micro segment and is taken as 0.001m.

6. The deformation detection method for a curved beam according to claim 5, characterized in that: Also included is the N The deformation caused by (z) is decomposed along the W axis, and the specific formula is as follows: Among them, dw N is the displacement change in the W-axis direction caused by the axial force in the Z-axis direction, ε N (z) is the strain caused by the axial force in the Z direction at the Z position, is the angle between the Z axis and the UOW plane at the Z position, is the angle between the Z axis and the VOW plane at the Z position, is the angle between the Z axis and the UOV plane at the Z position, dz is the length of the micro segment and is taken as 0.001m.

7. The deformation detection method for a curved beam according to claim 6, characterized in that: It also includes calculating the total deformation in the U-axis direction. The specific formula is as follows: Among them, μ is the total deformation in the U-axis direction, dμ My is the displacement change in the U-axis direction caused by the bending moment around the Y-axis, dμ N is the displacement change in the U-axis direction caused by the axial force in the Z-axis direction, and 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 set to 0, θ My (z i ) is the angle change caused by the bending moment around the Y axis at the i-th micro-segment, is the angle between the Z axis and the VOW plane at the Z position, ε i N (z) is the strain caused by the axial force in the Z axis at the i-th micro segment, L is the distance between the Z position and the origin of the UVW coordinate, is the angle between the Z axis and the VOW plane at the Z=0 position.

8. The deformation detection method for a curved beam according to claim 7, wherein: It also includes calculating the total deformation in the V-axis direction. The specific formula is as follows: Where v is the total deformation in the V-axis direction, dv Mx is the displacement change in the V-axis direction caused by the bending moment around the X-axis, dv N is the displacement change in the V-axis direction caused by the axial force in the Z-axis direction, C4 is the displacement in the Y-axis direction at Z=0 and is taken as 0, θ Mx (z i ) is the angle change caused by the bending moment around the X axis at the i-th micro-segment, is the angle between the Z axis and the UOW plane at the Z position, ε i N (z) is the strain caused by the axial force in the Z-axis direction at the i-th micro-segment, and C3 is the cross-sectional rotation angle θ at the Z-axis Z=0. Mx (0), is the angle between the Z axis and the UOW plane at the Z=0 position, and L is the distance between the Z position and the origin of the UVW coordinate system.

9. The deformation detection method for a curved beam according to claim 6, wherein: It also includes the calculation of the total deformation in the W-axis direction. The specific formula is as follows: Where w is the total deformation in the W-axis direction, dw Mx is the displacement change in the W-axis direction caused by the bending moment around the X-axis, dw My is the displacement change in the W-axis direction caused by the bending moment around the Y-axis, dw N is the displacement change in the W-axis direction caused by the axial force in the Z-axis direction, C5 is the displacement caused by the Z-axis tension at Z=0 and is taken as 0, θ Mx (z i ) is the angle change caused by the bending moment around the X axis at the i-th micro-segment, is the angle between the Z axis and the UOW plane 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, is the angle between the Z axis and the VOW plane at the Z position, ε i N (z) is the strain caused by the axial force in the Z axis at the i-th micro segment, is the angle between the Z axis and the UOV plane at the Z position, and C1 is the cross-sectional rotation angle θ at the Z axis Z = 0 My (0), is the angle between the Z axis and the VOW plane at Z = 0, and C3 is the cross-sectional rotation angle θ at Z = 0. Mx (0), is the angle between the Z axis and the UOW plane at the Z=0 position, and L is the distance between the Z position and the origin of the UVW coordinate system.

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