An analysis method and system for failure of a submarine cable bend limiter

Abstract

The application discloses a submarine cable bending limiter failure analysis method and system, and relates to the field of submarine cable engineering equipment. The submarine cable bending limiter failure analysis method comprises the following steps: controlling an ultrasonic detection unit to emit ultrasonic signals to a submarine cable bending limiter along multiple different scanning paths, and receiving echo signals returned by each scanning path; determining the propagation time of the ultrasonic signals along the corresponding scanning path in the structure of the submarine cable bending limiter based on the echo signals of each scanning path; constructing an erosion damage distribution map of the submarine cable bending limiter based on the difference between the current propagation time and the reference propagation time of all scanning paths; and integrating the erosion damage distribution map and strain distribution data into a pre-constructed digital twin model of the submarine cable bending limiter, performing spatial registration and fusion analysis, and evaluating the failure risk. The application can evaluate the failure state of the bending limiter under the action of real complex load and long-term corrosion.

Description

A method and system for analyzing the failure of submarine cable bend limiters Technical Field

[0001] This application relates to the field of submarine cable engineering equipment technology, and in particular to an analysis method and system for the failure of submarine cable bending limiters. Background Technology

[0002] The stable operation of offshore wind farms is crucial for energy supply, and the performance of submarine cable bend limiters, as key devices for protecting submarine cables, directly affects the safety of wind farms.

[0003] Currently, failure analysis of submarine cable bending limiters mainly relies on offline, static mechanical model simulation and periodic local manual analysis, which has obvious limitations. Summary of the Invention

[0004] This application provides a method and system for analyzing the failure of a submarine cable bending limiter, which can evaluate the failure state of the bending limiter under real complex loads and long-term corrosion.

[0005] Firstly, this application provides a method for analyzing the failure of a submarine cable bending limiter, the method comprising:

[0006] The multi-sensor system is controlled to move to the test position of the submarine cable bending limiter, wherein the multi-sensor system includes at least an ultrasonic detection unit;

[0007] The ultrasonic detection unit is controlled to emit ultrasonic signals toward the submarine cable bending limiter along multiple different scanning paths and receive echo signals returned from each scanning path; wherein, the multiple different scanning paths include at least one main scanning path extending along the axial direction of the submarine cable bending limiter and at least one circumferential scanning path surrounding the circumference of the submarine cable bending limiter, and the main scanning path and the circumferential scanning path intersect to form a grid-like detection layout;

[0008] Based on the echo signal of each of the scanning paths, the propagation time of the ultrasonic signal along the corresponding scanning path in the structure of the submarine cable bending limiter is determined and recorded as the current propagation time.

[0009] Obtain the reference propagation time of the submarine cable bending limiter in a healthy state, and construct a corrosion damage distribution map of the submarine cable bending limiter based on the difference between the current propagation time and the reference propagation time for all the scanning paths;

[0010] Acquire strain distribution data collected by multiple strain sensing units deployed on the submarine cable bending limiter, wherein the strain sensing units are located at the intersection of the main scanning path and the circumferential scanning path.

[0011] The corrosion damage distribution map and the strain distribution data are integrated into a pre-built digital twin model of the submarine cable bending limiter for spatial registration and fusion analysis to assess the failure risk.

[0012] Secondly, this application provides an analysis system for the failure of a submarine cable bending limiter, including a multi-sensor system, multiple strain sensing units deployed on the submarine cable bending limiter, and an analysis device for the failure of the submarine cable bending limiter. The analysis device for the failure of the submarine cable bending limiter includes:

[0013] A control module is used to control the movement of the multi-sensor system to the test position of the submarine cable bending limiter, wherein the multi-sensor system includes at least an ultrasonic detection unit;

[0014] The scanning module is used to control the ultrasonic detection unit to emit ultrasonic signals to the submarine cable bending limiter along multiple different scanning paths, and to receive the echo signals returned from each of the scanning paths; wherein, the multiple different scanning paths include at least one main scanning path extending along the axial direction of the submarine cable bending limiter and at least one circumferential scanning path surrounding the circumference of the submarine cable bending limiter, and the main scanning path and the circumferential scanning path intersect to form a grid-like detection layout;

[0015] The time calculation module is used to determine the propagation time of the ultrasonic signal along the corresponding scanning path in the structure of the submarine cable bending limiter based on the echo signal of each scanning path, and record it as the current propagation time;

[0016] The corrosion construction module is used to obtain the reference propagation time of the submarine cable bending limiter in a healthy state, and construct the corrosion damage distribution map of the submarine cable bending limiter based on the difference between the current propagation time and the reference propagation time for all the scanning paths.

[0017] The acquisition module is used to acquire strain distribution data collected by multiple strain sensing units deployed on the submarine cable bending limiter, wherein the strain sensing units are located at the intersection of the main scanning path and the circumferential scanning path.

[0018] The analysis module is used to integrate the corrosion damage distribution map and the strain distribution data into a pre-built digital twin model of the submarine cable bending limiter, and to perform spatial registration and fusion analysis to assess the failure risk.

[0019] The method and system for analyzing the failure of submarine cable bending limiters provided in this application have the following advantages:

[0020] This application utilizes an ultrasonic testing unit to transmit ultrasonic signals to a submarine cable bending limiter along multiple different scanning paths and receives echo signals from each scanning path. Based on the echo signals from each scanning path, the propagation time of the ultrasonic signal along the corresponding scanning path within the structure of the submarine cable bending limiter is determined. Based on the difference between the current propagation time and the reference propagation time for all scanning paths, a corrosion damage distribution map of the submarine cable bending limiter is constructed. The corrosion damage distribution map and strain distribution data are integrated into a pre-constructed digital twin model of the submarine cable bending limiter for spatial registration and fusion analysis to assess failure risk. This application achieves the determination of structural failure risk under the coupled effects of corrosion and stress through multi-sensor detection and digital twin model fusion analysis technology. It establishes a closed-loop technology from automatic data acquisition, damage quantification imaging, and model-driven risk assessment. On the one hand, it can assess the actual state of the bending limiter under real complex loads and long-term corrosion; on the other hand, it significantly reduces the subjectivity and uncertainty caused by human intervention, significantly improving the overall efficiency and systematicness from raw detection data to risk decision output, providing reliable technical support for predictive maintenance of submarine cable bending limiters. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0022] Figure 1 is a flowchart illustrating the analysis method for the failure of a submarine cable bending limiter provided in an embodiment of this application;

[0023] Figure 2 is a structural block diagram of an analysis system for the failure of a submarine cable bending limiter provided in an embodiment of this application. Detailed Implementation

[0024] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0025] Please refer to Figure 1, which is a flowchart illustrating an analysis method for the failure of a submarine cable bending limiter according to an embodiment of this application. In this embodiment, the analysis method for the failure of a submarine cable bending limiter includes steps S10-S60:

[0026] S10, control the multi-sensor system to move to the test position of the submarine cable bending limiter, wherein the multi-sensor system includes at least an ultrasonic detection unit.

[0027] The testing station refers to the location where the cable bending limiter can be effectively inspected. The multi-sensor system can be mounted on an underwater robot (such as an ROV) or a fixed robotic arm. By controlling the movement and attitude adjustment of the mounting platform, the multi-sensor system can be precisely positioned to one or more preset testing stations. Each station corresponds to a different area on the bending limiter to be inspected (e.g., the J-shaped tube outlet transition section, the middle suspension section, the seabed contact section, etc.), thereby achieving segmented and full-coverage inspection of the entire cable bending limiter.

[0028] In some implementations, the multi-sensor system may also include an underwater camera. Before ultrasonic testing begins, real-time images of the detection area of ​​the cable bend limiter are acquired via the underwater camera to identify whether there is marine life attached, sediment covering, or foreign object obstruction on its surface. If obstruction is detected affecting ultrasonic coupling and signal quality, a high-pressure water jet is activated for cleaning.

[0029] S20 controls the ultrasonic detection unit to transmit ultrasonic signals to the submarine cable bending limiter along multiple different scanning paths and to receive the echo signals returned from each scanning path.

[0030] The ultrasonic testing unit includes an ultrasonic transmitting probe and an ultrasonic receiving probe. The ultrasonic transmitting probe is used to excite ultrasonic signals of specific waveforms and frequencies, while the ultrasonic receiving probe is used to capture echo signals reflected, scattered, or transmitted back from inside the structure.

[0031] In some implementations, the scanning path of the ultrasonic testing unit can be planned, as follows:

[0032] Based on the three-dimensional structural model of the submarine cable bending limiter, at least two sets of intersecting scanning paths are planned in the area to be inspected. These at least two sets of intersecting scanning paths include at least one main scanning path extending along the axis of the submarine cable bending limiter, and at least one circumferential scanning path encircling the submarine cable bending limiter, to form a gridded scanning coverage within the area to be inspected. The axial step size of the main scanning path is 0.2~0.5mm, the circumferential step size of the circumferential scanning path is 0.5°~1°, and the distance between adjacent main scanning paths is no greater than 1 / 2 of the ultrasonic guided wave wavelength.

[0033] That is, for each test station (or area to be inspected), there are at least two sets of spatially intersecting scanning paths. One set is the main scanning path extending along the axis of the cable bending limiter, used to detect the defect distribution and material uniformity along the length direction. The other set is at least one circumferential scanning path around the cable bending limiter, used to evaluate the corrosion uniformity and circumferential cracks in the cross-sectional direction. Through the intersection and combination of axial and circumferential paths, a gridded scanning coverage is formed in the area to be inspected, thereby obtaining dense inspection data points in the cable bending limiter structure.

[0034] In some implementations, when scanning the cable bend limiter along each scanning path, ultrasonic guided wave signals can be emitted according to a preset excitation strategy. The preset excitation strategy refers to signal excitation according to a target ultrasonic guided wave mode and a target frequency range, which can be predetermined by analyzing the guided wave dispersion characteristics of the cable bend limiter's structural parameters and material properties.

[0035] Specifically, before testing, the guided wave dispersion curve can be calculated using numerical methods such as the semi-analytical finite element method, based on the specific structural parameters (e.g., wall thickness, diameter, curvature) and material properties (e.g., density, elastic modulus) of the target bend limiter. By analyzing the dispersion curve, guided wave modes and frequency windows that are sensitive to wall thickness reduction (corrosion) and exhibit stable propagation characteristics and concentrated energy within the structure are selected as excitation parameters. Since the submarine cable bend limiter is deployed in an underwater environment, water flow disturbances, marine organism attachment, and reflections from the curved surface of the structure can all interfere with the ultrasonic signal. The excitation parameters selected through dispersion characteristic analysis ensure stable propagation characteristics of the guided wave within the target structure, effectively resisting underwater clutter interference and guaranteeing the effectiveness and resolvability of the echo signal.

[0036] S30, based on the echo signal of each scanning path, determine the propagation time of the ultrasonic signal along the corresponding scanning path in the structure of the submarine cable bending limiter, and record it as the current propagation time.

[0037] In some implementations, for the echo signal of each scan path, the following steps are performed, including steps a1 to a4:

[0038] a1. Perform continuous wavelet transform on the echo signal to obtain the time-frequency curve.

[0039] a2, perform energy threshold filtering on the time-frequency curve to identify the energy ridge line in the time-frequency curve;

[0040] a3. Find the first energy peak point on the energy ridge line along the time axis, and determine the time point of the first energy peak point on the time axis as the moment when the first ultrasonic wave arrives at the receiving probe of the ultrasonic detection unit, and record it as the receiving time point;

[0041] a4. The current propagation time is determined based on the receiving time point and the ultrasonic transmission time point.

[0042] More specifically, before starting the signal processing flow, it is necessary to ensure that a single scanning path meets the following consistency requirements, including: (1) consistent probe posture: the posture of the ultrasonic transmitting probe and the receiving probe relative to the detection surface must be stable throughout the entire process, the vertical deviation between the probe and the detection surface is less than the preset angle threshold, and the distance between the probe and the detection surface remains constant throughout the scanning process of the entire path, so as to avoid deviations in ultrasonic incident angle and propagation path length due to posture fluctuations; (2) consistent ultrasonic transmission parameters: the ultrasonic transmission parameters of the current path must be completely matched with the preset excitation strategy, and the core parameters have no deviation.

[0043] In step a1 above, after acquiring the echo signal of each scanning path, the echo signal is first bandpass filtered so that the filtering frequency is consistent with the preset excitation frequency range, so as to filter out invalid signals such as water flow noise and equipment electromagnetic interference.

[0044] When performing continuous wavelet transform on the echo signal, the Morlet wavelet can be selected. Through continuous wavelet transform, the original one-dimensional time-domain echo signal is converted into a two-dimensional time-frequency energy matrix. In this matrix, the rows correspond to the time axis (synchronized with the propagation time of the ultrasonic guided wave), and the columns correspond to the frequency axis (covering a preset frequency range of the target mode, such as 70~180kHz). The element values ​​in the time-frequency energy matrix represent the signal energy intensity within the corresponding time-frequency unit, intuitively presenting the dynamic evolution of the instantaneous frequency with propagation time. It clearly preserves the characteristic trajectory of the ultrasonic guided wave propagating in the bending limiter and after reflection / scattering by corrosion defects. Finally, a visualized time-frequency curve (or time spectrum) is generated based on this time-frequency energy matrix.

[0045] Furthermore, to accurately distinguish between effective signal components and background noise, this application employs a local dynamic threshold screening method to avoid the limitations of a single fixed threshold in adapting to signals with non-uniform energy distribution. Specifically, a sliding window (e.g., a 5×5 time-frequency unit, the window size of which can be adjusted according to the signal frequency resolution) is first set. Centered on each time-frequency point, the entire time-frequency energy matrix is ​​traversed, and the mean energy (μ) and standard deviation (σ) within the window are calculated. Then, a dynamic threshold is set to "μ+mσ", where m can be 2 or 3, but this application is not limited to this. Subsequently, time-frequency regions with energy values ​​exceeding this threshold are identified as potential effective signal regions, and a binary mask image is generated simultaneously. In the mask image, "1" corresponds to a high-energy effective signal region, and "0" corresponds to a low-energy background noise region, thereby achieving dynamic suppression of fluctuating background noise while fully preserving the low-amplitude effective signal corresponding to weak corrosion defects.

[0046] In step a2 above, based on the identified high-energy region, at each time point, the frequency point of the local energy maximum is searched as a candidate point. Then, based on the constraints of time continuity and the smoothness of frequency change between adjacent time points, these discrete candidate points are connected into several continuous ridge trajectory, which is the energy ridge.

[0047] Step a3 above may include:

[0048] The first step is to extract the time series and corresponding energy amplitude series from the energy ridges that characterize the main energy propagation path of the signal, forming a "time-energy" dataset. Optionally, the energy series can also be subjected to adaptive smoothing filtering to suppress the interference of random noise on peak detection.

[0049] The second step involves executing a peak detection algorithm on the smoothed energy curve: local energy maxima points with amplitudes greater than or equal to an amplitude threshold, peak widths greater than or equal to a preset minimum peak width, and inter-peak distances greater than or equal to a preset minimum inter-peak distance are selected as candidate points for the arrival time of the first wave. The amplitude threshold, preset minimum peak width, and preset minimum inter-peak distance are set empirically or adjusted based on actual conditions, and are not inherently limited.

[0050] The third step is to sort all the candidate points after screening by their occurrence time along the time axis from front to back, and select the candidate point with the earliest occurrence time as the first energy peak point corresponding to the first wave.

[0051] Optionally, to avoid misjudging prematurely appearing isolated noise as the first wave, cross-validation can be performed by combining the occurrence time and energy distribution of other candidate points. Specifically, after initially determining the first energy peak point, the first energy peak point and its neighboring sampling points (e.g., the left and right nearest ones) are selected, and the vertex of the local energy curve is fitted using a quadratic interpolation formula to obtain the final selected first energy peak point.

[0052] In some implementations, step a4 above may include:

[0053] The distance between the ultrasonic detection unit and the submarine cable bending limiter and the first propagation speed of ultrasound in seawater were obtained.

[0054] Based on the distance and the first propagation velocity, the time required for the ultrasound to travel back and forth between the ultrasonic detection unit and the submarine cable bending limiter is calculated as the water propagation time.

[0055] Calculate the time difference between the receiving time and the ultrasonic transmission time;

[0056] Subtract the water propagation time from the time difference to obtain the current propagation time.

[0057] More specifically, the multi-sensor system may also include a laser ranging module integrated with the ultrasonic detection unit. This laser ranging module measures the straight-line distance L between the probe end face and the outer surface of the cable bending limiter perpendicular to the ultrasonic emission direction. This straight-line distance L is the distance between the ultrasonic detection unit and the cable bending limiter. Considering that the surface of the bending limiter is curved, multiple evenly distributed measuring points can be selected for measurement, and the average of the straight-line distances of all measuring points can be taken as the distance between the ultrasonic detection unit and the cable bending limiter.

[0058] In the above scheme, the first propagation velocity can be determined based on the fundamental propagation velocity v_0 of ultrasonic longitudinal waves in seawater, and corrected by combining the real-time temperature T and salinity S of the detection environment. The correction formula refers to the marine acoustic standard: v_x = v_0 + 2.12T − 0.0011T 2 +1.38(S−35) is used to calculate the actual ultrasonic propagation velocity v_x in seawater, which is the first propagation velocity.

[0059] Understandably, the ultrasound starts from the transmitting probe of the ultrasound detection unit, propagates through the seawater layer to the surface of the bending limiter, and then reflects back to the receiving probe. The propagation path is: probe - seawater - limiter surface - seawater - probe. The total water layer propagation distance is 2L. Therefore, the water path propagation time is: t = 2L / v_x.

[0060] Then, taking the instantaneous moment when the excitation signal is output by the signal excitation module of the ultrasonic detection unit as the transmission time point, the current propagation time of the corresponding scanning path is finally determined by the formula: Current propagation time = Reception time point - Ultrasonic transmission time point - Water propagation time.

[0061] S40: Obtain the baseline propagation time of the submarine cable bending limiter in a healthy state, and construct a corrosion damage distribution map of the submarine cable bending limiter based on the difference between the current propagation time and the baseline propagation time of all scan paths.

[0062] Specifically, before the submarine cable bending limiter is installed at the factory, it is subjected to full-station baseline testing according to the same ultrasonic testing parameters (including frequency range, probe posture, and scanning path planning) as in step S20 above. The propagation time corresponding to each scanning path is measured and used as the reference propagation time. Then, the reference propagation time is associated and bound with the corresponding scanning path number and the spatial coordinates (x, y, z) of the path start and end points, and stored in the testing database in a structured format of "scanning path-spatial position-reference propagation time" to form a reference dataset.

[0063] In some implementations, the deviation between the current propagation time of each scanning path and the reference propagation time at the corresponding position can be calculated to obtain the propagation time change; then, based on the propagation time change and spatial position of all scanning paths, a corrosion damage distribution map is constructed using a spatial interpolation algorithm.

[0064] More specifically, for each scanning path, the difference between the current propagation time and the reference propagation time is calculated, and this difference is used as the corrosion index for the corresponding detection location point on the scanning path; the absolute value of the difference is positively correlated with the degree of corrosion damage at that location. Then, the spatial coordinates (x, y, z) of all detection points and their corresponding corrosion indices are interpolated using spatial interpolation algorithms (such as Kriging interpolation or radial basis function interpolation) onto the dense grid nodes on the surface of the bending limiter, ultimately generating a continuous corrosion index distribution map covering the entire detection area.

[0065] S50 acquires strain distribution data collected by multiple strain sensing units deployed on the submarine cable bending limiter.

[0066] Specifically, at least one strain sensing unit is deployed at the intersection of the main scanning path and the circumferential scanning path. The strain sensing unit can be a fiber grating (FBG) sensor. An array of FBG sensors is deployed on the submarine cable bending limiter. Each time the ultrasonic probe emits a signal at a specific location, strain data collected by all FBG sensor arrays at that moment is synchronously acquired. Then, the strain data from the discrete FBG sensors are processed using a spatial interpolation algorithm (such as interpolation based on the shape function of the finite element model) to generate strain distribution data covering the entire surface of the bending limiter.

[0067] S60 integrates corrosion damage distribution maps and strain distribution data into a pre-built digital twin model of the submarine cable bending limiter for spatial registration and fusion analysis to assess failure risk.

[0068] In some implementations, the corrosion damage distribution map is spatially registered with the digital twin model, and the corrosion risk area is marked in the digital twin model; the strain distribution data is mapped to the digital twin model to obtain the structural stress distribution; the overlap between the corrosion risk area and the structural stress distribution is comprehensively analyzed to assess the failure risk under the coupling effect of corrosion and stress.

[0069] In some implementations, based on the change in propagation time at each location in the corrosion damage distribution map, spatial locations where the change in propagation time is greater than a preset threshold are identified and recorded as risk locations.

[0070] Areas that are interconnected or meet the spatial proximity condition in the risk location are marked as corrosion risk areas in the digital twin model.

[0071] More specifically, in the digital twin modeling stage, a global coordinate system of the submarine cable bending limiter can be established with the center of the J-tube interface flange as the origin, and the X-axis is set along the axial direction of the submarine cable, the Y-axis along the horizontal radial direction, and the Z-axis along the vertical radial direction to form a unified spatial positioning reference. In addition, the multi-sensing system can also be equipped with a high-precision positioning system, which can convert the original coordinates of all detection points to this global coordinate system to achieve coordinate alignment.

[0072] Then, the discrete data points of the corrosion damage distribution map are converted into a structured format, and each data point contains attribute information: [X, Y, Z, Δt, D_Level]. Among them, X, Y, and Z are the three-dimensional coordinates of the detection point in the global coordinate system, Δt is the change in propagation time at this point, and D_Level is the corrosion level divided based on Δt. The corrosion level is determined according to the comparison results of Δt with multiple thresholds. For example, when Δt < k1, it indicates healthy; when k1 ≤ Δt < k2, it indicates mild corrosion; when k2 ≤ Δt < k3, it indicates moderate corrosion; when Δt > k3, it indicates severe corrosion. Among them, k1, k2, and k3 are all preset thresholds. The corrosion level can be represented numerically. For example, 0 represents healthy, 1 represents mild, 2 represents moderate, and 3 represents severe.

[0073] After that, the nearest point projection method or the normal projection method is used to project the structured corrosion data point cloud onto the surface mesh of the digital twin model to achieve the alignment of the corrosion data with the geometric shape of the model, ensuring that each corrosion data point can correspond to the specific physical location of the model.

[0074] In some embodiments, the data points with a corrosion level of moderate or severe can be defined as corrosion points, and their corresponding spatial positions are the risk positions. Then, through connected component analysis or spatial proximity algorithms (such as setting a proximity threshold ≤ 10 mm), the corrosion points that are connected to each other or meet the proximity conditions are aggregated into continuous regions and marked as corrosion risk regions. Finally, in the digital twin model user interface, the corrosion risk regions are covered with a specific color (such as translucent red) to achieve intuitive highlighting of the risk positions.

[0075] In the above embodiments, the mapping process for strain distribution data adopts the same processing logic as that for corrosion damage distribution maps: the strain distribution data is converted into a structured format adapted to the global coordinate system, with each data point containing [X, Y, Z, F]. Here, X, Y, and Z are the three-dimensional coordinates in the global coordinate system, and F is the measured strain value at that point. Then, based on the structured strain data, the stress value is calculated using the material constitutive equation of the bending limiter (such as Hooke's law). Finally, on the surface of the digital twin model, an equivalent stress cloud map or a maximum principal stress cloud map is rendered in chromatographic form to visually present the stress level distribution in each region of the structure. Furthermore, regions where data points with stress exceeding a preset stress threshold are connected can be marked as high-stress regions.

[0076] After overlaying the corrosion risk area layer and the stress distribution cloud map layer in the digital twin model, the linked analysis and assessment of the failure risk under the coupled effects of corrosion and stress can include:

[0077] If the corrosion risk area overlaps with the high stress area, it is determined that "there is a risk of failure".

[0078] If the corrosion risk area does not overlap with the high stress area, the corrosion level of the corrosion risk area should be further assessed: a moderately corroded area is classified as "low risk" and requires routine inspection; a severely corroded area is classified as "medium risk" and requires close monitoring of the corrosion development rate.

[0079] This application controls an ultrasonic testing unit to emit ultrasonic signals to a submarine cable bending limiter along multiple different scanning paths and receives the echo signals returned from each scanning path. Based on the echo signals of each scanning path, the propagation time of the ultrasonic signal along the corresponding scanning path in the structure of the submarine cable bending limiter is determined. Based on the difference between the current propagation time and the reference propagation time of all scanning paths, a corrosion damage distribution map of the submarine cable bending limiter is constructed. The corrosion damage distribution map and strain distribution data are integrated into a pre-constructed digital twin model of the submarine cable bending limiter for spatial registration and fusion analysis to assess the failure risk. This application realizes the determination of structural failure risk under the coupled effects of corrosion and stress through the fusion analysis technology of multi-sensor detection and digital twin model, and constructs a complete technical closed loop from automatic data acquisition, damage quantification imaging, and model-driven risk assessment. On the one hand, it can assess the actual state of the bending limiter under real complex loads and long-term corrosion. On the other hand, it can significantly reduce the subjectivity and uncertainty caused by human intervention, and significantly improve the overall efficiency and systematicness from raw detection data to risk decision output, providing reliable technical support for predictive maintenance of submarine cable bending limiters.

[0080] This application also provides an analysis system for the failure of a submarine cable bending limiter, including a multi-sensor system, multiple strain sensing units deployed on the submarine cable bending limiter, and an analysis device for the failure of the submarine cable bending limiter. The analysis device for the failure of the submarine cable bending limiter includes:

[0081] The control module is used to control the movement of the multi-sensor system to the test position of the submarine cable bending limiter, wherein the multi-sensor system includes at least an ultrasonic detection unit;

[0082] The scanning module is used to control the ultrasonic detection unit to emit ultrasonic signals to the submarine cable bending limiter along multiple different scanning paths and to receive the echo signals returned from each scanning path. The multiple different scanning paths include at least one main scanning path extending along the axis of the submarine cable bending limiter and at least one circumferential scanning path around the circumference of the submarine cable bending limiter. The main scanning path and the circumferential scanning path intersect to form a grid-like detection layout.

[0083] The time calculation module is used to determine the propagation time of the ultrasonic signal along the corresponding scanning path in the structure of the submarine cable bending limiter based on the echo signal of each scanning path, and record it as the current propagation time;

[0084] The corrosion construction module is used to obtain the baseline propagation time of the submarine cable bending limiter in a healthy state, and to construct the corrosion damage distribution map of the submarine cable bending limiter based on the difference between the current propagation time and the baseline propagation time for all scan paths.

[0085] The acquisition module is used to acquire strain distribution data collected by multiple strain sensing units deployed on the submarine cable bending limiter. The strain sensing units are set at the intersection of the main scanning path and the circumferential scanning path.

[0086] The analysis module integrates corrosion damage distribution maps and strain distribution data into a pre-built digital twin model of the submarine cable bending limiter for spatial registration and fusion analysis to assess failure risk.

[0087] Please refer to Figure 2, which exemplarily shows a structural block diagram of a submarine cable bending limiter failure analysis system according to this application. The system includes a multi-sensor system 1, multiple strain sensing units 2 deployed on the submarine cable bending limiter 4, and a submarine cable bending limiter failure analysis device 3. The multi-sensor system 1 can be mounted on an underwater robot or a fixed robotic arm, and includes at least sensing modules such as an ultrasonic detection unit, an underwater camera, and a positioning system. The submarine cable bending limiter failure analysis device 3 can be implemented using a computer processing device. This computer processing device includes a processor and a digital twin platform deployed thereon for executing the submarine cable bending limiter failure analysis method described in the above embodiments. The multi-sensor system 1 is communicatively connected to the processor of the computer processing device to achieve real-time transmission and processing of detection data.

[0088] It should be noted that the specific implementation process and beneficial effects of each of the above modules correspond one-to-one with the steps of the analysis of the failure of the submarine cable bending limiter in the above embodiment, and will not be repeated here.

[0089] The above are only some embodiments of this application and do not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A method for analyzing the failure of a submarine cable bending limiter, characterized in that, include: The system controls a multi-sensor system to move to the test position of the submarine cable bending limiter. The multi-sensor system includes at least an ultrasonic detection unit. The ultrasonic detection unit is controlled to emit ultrasonic signals towards the submarine cable bending limiter along multiple different scanning paths and receives echo signals returned from each scanning path. The multiple different scanning paths include at least one main scanning path extending along the axis of the submarine cable bending limiter and at least one circumferential scanning path surrounding the circumference of the submarine cable bending limiter. The main scanning path and the circumferential scanning path intersect to form a grid-like detection layout. While scanning the submarine cable bending limiter along each scanning path, the ultrasonic detection unit emits ultrasonic guided wave signals according to a preset excitation strategy. The preset excitation strategy refers to signal excitation according to a target ultrasonic guided wave mode and a target frequency range, where the target ultrasonic guided wave mode and target frequency range are determined by the structure of the submarine cable bending limiter. The structural parameters and material properties are pre-determined through guided wave dispersion characteristic analysis; based on the echo signal of each scanning path, the propagation time of the ultrasonic signal along the corresponding scanning path in the structure of the submarine cable bending limiter is determined and recorded as the current propagation time; the reference propagation time of the submarine cable bending limiter in a healthy state is obtained, and based on the difference between the current propagation time and the reference propagation time corresponding to all scanning paths, a corrosion damage distribution map of the submarine cable bending limiter is constructed; strain distribution data collected by multiple strain sensing units deployed on the submarine cable bending limiter are obtained, wherein the strain sensing units are located at the intersection nodes of the main scanning path and the circumferential scanning path; the corrosion damage distribution map and the strain distribution data are integrated into a pre-constructed digital twin model of the submarine cable bending limiter for spatial registration and fusion analysis to assess the failure risk.

2. The method for analyzing the failure of a submarine cable bending limiter as described in claim 1, characterized in that, The determination of the propagation time of the ultrasonic signal along the corresponding scanning path in the structure of the submarine cable bending limiter based on the echo signal of each scanning path includes: performing the following operations on the echo signal of each scanning path: performing continuous wavelet transform on the echo signal to obtain a time-frequency curve; performing energy threshold filtering on the time-frequency curve to identify the energy ridge line in the time-frequency curve; finding the first energy peak point on the energy ridge line along the time axis, determining the time point of the first energy peak point on the time axis as the time when the first ultrasonic wave arrives at the receiving probe of the ultrasonic detection unit, and recording it as the receiving time point; obtaining the ultrasonic emission time point, and determining the current propagation time based on the receiving time point and the ultrasonic emission time point.

3. The method for analyzing the failure of a submarine cable bending limiter as described in claim 2, characterized in that, Determining the current propagation time based on the receiving time point and the ultrasonic transmission time point includes: acquiring the distance between the ultrasonic detection unit and the submarine cable bending limiter and the first propagation speed of the ultrasonic wave in seawater; calculating the time required for the ultrasonic wave to travel back and forth between the ultrasonic detection unit and the submarine cable bending limiter based on the distance and the first propagation speed, as the water propagation time; calculating the time difference between the receiving time point and the ultrasonic transmission time point; and subtracting the water propagation time from the time difference to obtain the current propagation time.

4. The analytical method for the failure of a submarine cable bending limiter as described in any one of claims 1 to 3, characterized in that, The step of constructing a corrosion damage distribution map of the submarine cable bending limiter based on the difference between the current propagation time and the reference propagation time for all the scanning paths includes: calculating the deviation between the current propagation time of each scanning path and the reference propagation time at the corresponding position to obtain the propagation time change; and constructing the corrosion damage distribution map based on the propagation time change and spatial position for all the scanning paths using a spatial interpolation algorithm.

5. The method for analyzing the failure of a submarine cable bending limiter as described in claim 4, characterized in that, The process of integrating the corrosion damage distribution map and the strain distribution data into a pre-constructed digital twin model of the submarine cable bending limiter for spatial registration and fusion analysis to assess failure risk includes: spatially registering the corrosion damage distribution map with the digital twin model, and marking corrosion risk areas in the digital twin model based on the propagation time variation; mapping the strain distribution data to the digital twin model to obtain the structural stress distribution; and comprehensively analyzing the overlap between the corrosion risk areas and the structural stress distribution to assess the failure risk under the coupling effect of corrosion and stress.

6. The method for analyzing the failure of a submarine cable bending limiter as described in claim 5, characterized in that, The step of marking corrosion risk areas in the digital twin model based on the propagation time change includes: identifying spatial locations where the propagation time change is greater than a preset threshold based on the propagation time change at each location in the corrosion damage distribution map, and recording them as risk locations; marking interconnected or spatially adjacent areas among the risk locations as corrosion risk areas in the digital twin model.

7. The method for analyzing the failure of a submarine cable bending limiter as described in claim 1, characterized in that, The method further includes: planning at least two intersecting scanning paths in the area to be detected based on the three-dimensional structural model of the submarine cable bending limiter.

8. An analysis system for the failure of a submarine cable bending limiter, characterized in that, The system includes a multi-sensor system, multiple strain sensing units deployed on a submarine cable bending limiter, and an analysis device for submarine cable bending limiter failure. The analysis device includes: a control module for controlling the multi-sensor system to move to the test position on the submarine cable bending limiter, wherein the multi-sensor system includes at least an ultrasonic detection unit; and a scanning module for controlling the ultrasonic detection unit to emit ultrasonic signals towards the submarine cable bending limiter along multiple different scanning paths and to receive echo signals returned from each scanning path. The multiple different scanning paths include at least one main scanning path extending along the axis of the submarine cable bending limiter and at least one circumferential scanning path surrounding the circumference of the submarine cable bending limiter, the main scanning path and the circumferential scanning path intersecting to form a grid-like detection layout. While scanning the submarine cable bending limiter along each scanning path, the ultrasonic detection unit emits ultrasonic guided wave signals according to a preset excitation strategy. The preset excitation strategy refers to signal excitation according to the target ultrasonic guided wave mode and the target frequency range, and the target ultrasonic guided wave... The wave modes and target frequency range are predetermined through guided wave dispersion characteristic analysis of the structural parameters and material properties of the submarine cable bending limiter; the time calculation module is used to determine the propagation time of the ultrasonic signal along the corresponding scanning path in the structure of the submarine cable bending limiter based on the echo signal of each scanning path, and record it as the current propagation time; the corrosion construction module is used to obtain the reference propagation time of the submarine cable bending limiter in a healthy state, and construct the corrosion damage distribution map of the submarine cable bending limiter based on the difference between the current propagation time and the reference propagation time corresponding to all scanning paths; the acquisition module is used to acquire the strain distribution data collected by multiple strain sensing units deployed on the submarine cable bending limiter, wherein the strain sensing units are set at the intersection node of the main scanning path and the circumferential scanning path; the analysis module is used to integrate the corrosion damage distribution map and the strain distribution data into the pre-constructed digital twin model of the submarine cable bending limiter, and perform spatial registration and fusion analysis to assess the failure risk.

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