A system and method for monitoring the behavior of a marine flexible riser armor wire under stress

Abstract

The application discloses a monitoring system and method for stress behavior of armored steel wires of a marine flexible riser, and belongs to the field of marine riser monitoring. The system comprises monitoring modules, a transmission module, a control processing module and a warning module connected in sequence. The monitoring modules collect signal source information of a ship body and a riser; the signal source information is transmitted to the control processing module through the transmission module; preset system warning thresholds are generated, the system thresholds are updated and corrected according to the signal source information, the maximum stress value of the armored steel wires is calculated and it is judged whether the maximum stress value exceeds the warning thresholds, and the judgment result is transmitted to the warning module. The maximum stress value and the position of the armored steel wires of the riser at any moment are obtained and transmitted to the warning module, and if the maximum stress value exceeds the threshold, a warning is given. The signal source information of the ship body and the riser is indirectly measured to realize real-time monitoring of the stress safety of the riser, the technical path is integrated, the realization is convenient, and the safety during service of the catenary type and lazy wave type risers is greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of marine riser monitoring, specifically relating to a stress monitoring system and method. Background Technology

[0002] Marine flexible risers, as a crucial piece of equipment for deep-sea development, are widely used in marine nuclear power platforms to connect floating hulls and wellheads for oil and gas transfer. The flexible riser structure consists of a skeleton layer, a sealing layer, an armor layer, and a sheath layer. During service, the harsh operating environment of offshore oil and gas floating production systems and the excessive motion response of the hull can easily lead to excessive tensile, bending, and torsional stresses on the riser, causing failure of the internal armor wire structure. The medium transferred inside the riser is high-temperature, high-pressure oil and natural gas; any leak will cause irreparable damage. To ensure the stress safety of marine flexible risers during service, monitoring the stress behavior of their armor wires is essential.

[0003] Traditional marine flexible risers use externally mounted clamps to fix sensors (such as stress, acceleration, and fiber Bragg gratings) to the riser surface to measure physical quantities at specific locations, or to embed fiber Bragg grating sensors inside the riser for measurement. However, these monitoring methods have the following main shortcomings:

[0004] 1. For externally mounted sensors, under the action of random external loads, the location of the dangerous point of the riser changes in real time with the line shape, so it is impossible to accurately measure the stress extreme value and the dangerous location of the riser.

[0005] 2. For fiber Bragg grating sensors, the fiber Bragg grating sensors embedded in the riser are subject to complex loads during service, making them prone to breakage and difficult to monitor for long periods. Summary of the Invention

[0006] This invention provides a stress behavior monitoring system and method for the armored steel wire of a marine flexible riser, effectively overcoming the shortcomings of traditional monitoring methods. Real-time monitoring of riser stress safety can be achieved by indirectly measuring signal source information from the hull and riser. The integrated and unified technical approach facilitates implementation and significantly improves the safety of catenary and wave-shaped risers during service. Especially when the stress on the riser armored steel wire is excessive during service, early warning is emphasized, allowing personnel to adjust the hull position in advance to reduce the extreme stress value of the riser armored steel wire, thereby ensuring the safe operation of the riser during service.

[0007] A stress behavior monitoring system for armored steel wire of a marine flexible riser includes a riser monitoring module, a transmission module, a control and processing module, and an early warning module connected in sequence.

[0008] The monitoring module is used to collect signal source information from the hull and riser.

[0009] The transmission module is used to transmit the signal source information of the hull and riser collected by the monitoring module to the control processing module;

[0010] The control processing module is used to generate a preset system warning threshold based on a preset riser safety index; update and correct the maximum stress value of the riser according to the signal source information, and synchronously generate the corrected system threshold; determine whether the maximum stress value of the riser armor steel wire exceeds the warning threshold; and transmit the determination result to the warning module.

[0011] The early warning module is used to provide sound and / or image warnings based on the judgment results of the control processing module.

[0012] Furthermore, the riser monitoring module includes instrumentation devices for the hull, instrumentation devices for the catenary riser, and instrumentation devices for the wave-shaped riser.

[0013] The instrumentation devices on the hull include an inertial navigation system (IMU) and a GPS navigation system installed on the hull;

[0014] The instrumentation devices on the hull obtain the distance Z from the riser joint to the seabed and the horizontal distance S from the riser joint to the seabed tree through the inertial navigation system (IMU) and the GPS navigation system installed on the hull.

[0015] The instrumentation devices of the catenary riser include an angle sensor A installed in the suspended section of the riser;

[0016] The instrument for the catenary riser obtains the tilt angle value θ1 of riser section I through tilt sensor A installed in the suspended section of the riser.

[0017] The instrumentation devices of the lazy wave riser include tilt sensor a, tilt sensor B, tilt sensor C and tilt sensor D installed on the suspended section of the riser section;

[0018] The instruments of the catenary riser obtain the tilt angle values ​​θ2, θ3, θ4 and θ5 of the suspended section of the riser through the tilt angle sensor A installed on the suspended section of the riser.

[0019] Furthermore, the transmission module includes a data integration module and a display module;

[0020] The data integration module uses acoustic transmission and / or wired transmission methods to transmit the collected signal source information of the hull and riser to the computer host of the ship at sea.

[0021] The display module uses a monitor to display the processed data, which facilitates real-time display of the stress behavior of the riser armored steel wire.

[0022] Furthermore, the control processing module includes a data processing module and a data calculation module;

[0023] The data processing module performs preliminary processing on the collected signal source information of the hull and riser using abnormal data deletion and data selection methods.

[0024] The maximum stress value of the catenary riser armored steel wire at time t0 is compared with the maximum allowable stress of the catenary riser armored steel wire to determine whether the maximum stress value exceeds the warning threshold and to determine the safety status of the riser. The maximum stress value and location of the catenary riser armored steel wire at time t1 are calculated and updated accordingly. The maximum stress value of the riser at time t1 is compared with the maximum allowable stress of the riser armored steel wire to determine whether the maximum stress value exceeds the warning threshold and to determine the safety status of the riser. This process is repeated, updating and correcting the maximum stress value of the riser at the latest time tn. The maximum stress value of the catenary riser armored steel wire at time tn is compared with the maximum allowable stress of the riser armored steel wire to determine whether the maximum stress value exceeds the warning threshold and to determine the safety status of the riser.

[0025] The maximum stress value of the wave-shaped riser armored steel wire at time t0 is compared with the maximum allowable stress of the wave-shaped riser armored steel wire to determine whether the maximum stress value exceeds the warning threshold and to determine the safety status of the riser. The maximum stress value and location of the wave-shaped riser armored steel wire at time t1 are calculated and the maximum stress value of the riser is updated and corrected. The maximum stress value of the wave-shaped riser armored steel wire at time t1 is compared with the maximum allowable stress of the riser armored steel wire to determine whether the maximum stress value exceeds the warning threshold and to determine the safety status of the riser. This process is repeated to update and correct the maximum stress value of the riser at the latest time tn. The maximum stress value of the wave-shaped riser armored steel wire at time tn is compared with the maximum allowable stress of the riser armored steel wire to determine whether the maximum stress value exceeds the warning threshold and to determine the safety status of the riser.

[0026] The data calculation module substitutes the collected signal source information of the hull and riser into the force control equations of the catenary and wave-shaped risers to calculate the inclination angle, vertical force, axial force, and curvature of the entire catenary and / or wave-shaped riser. It then uses these inclination angles, vertical force, axial force, and curvature to calculate the stress state at any point on the rectangular cross-section armored steel wire at any given time, and further obtains the maximum stress value and location of the riser armored steel wire at any given time.

[0027] Furthermore, the warning module includes a sound module and an image display module;

[0028] The sound module is used to play safety warning sounds;

[0029] The image display module is used to display information on various monitoring quantities of the hull, including the inclination angle, vertical force, axial force and curvature of the entire catenary and / or wave-shaped riser at any given time, the stress state of any point on the rectangular cross-section armored steel wire at any given time, and the maximum stress value and location of the riser armored steel wire at any given time.

[0030] A stress behavior monitoring system for armored steel wire of a marine flexible riser includes the following steps:

[0031] Step 1: The monitoring module collects signal source information from the hull and riser.

[0032] Step 2: Transmit the signal source information of the hull and riser collected in Step 1 to the control processing module through the transmission module;

[0033] Step 3: The control processing module generates a preset system warning threshold based on the preset riser safety index; updates and corrects the maximum stress value of the riser according to the signal source information, and simultaneously generates the corrected system threshold; determines whether the maximum stress value of the catenary riser and / or lazy wave riser exceeds the warning threshold; and transmits the determination result to the warning module.

[0034] Step 4: Transmit the maximum stress value and position of the armored steel wire of the catenary riser and / or lazy wave riser obtained in Step 3 at any time to the early warning module. If the result exceeds the early warning threshold, an audio and / or visual warning will be issued.

[0035] If the catenary riser and / or lazy wave riser are determined to be in a dangerous state, the hull display module will start flashing to indicate that the current state is dangerous and play a pre-recorded voice audio signal to achieve a warning function.

[0036] Step 5: Judgment and cancellation of warning; When max(σy(tn))≤[σy], the catenary riser and / or lazy wave riser are considered to be in a safe state, and the warning will be cancelled.

[0037] Furthermore, step 3 includes:

[0038] Step 3.1: The control processing module calculates the inclination angle, vertical force, axial force and curvature of the entire catenary and / or wave-shaped riser based on the signal source information of the hull and riser collected.

[0039] Step 3.2: Based on the inclination angle, vertical force, axial force and curvature of the entire catenary and / or lazy wave type riser obtained in Step 3.1, calculate the stress state of any point of the rectangular cross section armored steel wire at any time.

[0040] Step 3.3: Calculate and obtain the maximum stress value and location of the catenary and / or lazy wave riser armored steel wire at any time;

[0041] Step 3.4: Compare the maximum stress value max(σy(t0)) of the catenary and / or lazy wave type riser armored steel wire at time t0 with the maximum allowable stress [σy] of the catenary and / or lazy wave type riser armored steel wire to determine whether the maximum stress value exceeds the warning threshold and to determine the safety status of the riser.

[0042] Where max is the maximum value symbol; σ is the stress of the catenary and / or wave-shaped riser armored steel wire; y is the number of the four angles of the rectangular section; the value is 1, 2, 3, 4; [σy] is the maximum allowable stress of the catenary and / or wave-shaped riser armored steel wire, that is, the maximum stress that the riser armored steel wire can withstand.

[0043] When max(σy(t0))≤[σy], the riser is considered to be in a safe state;

[0044] When max(σy(t0))>[σy], the riser is considered to be in a dangerous state.

[0045] Step 3.5: Calculate the maximum stress value and position max(σy(t1), L(t1)) of the catenary and / or wave-shaped riser armored steel wire at time t1, and update and correct the maximum allowable stress value of the riser armored steel wire; compare max(σy(t1)) with the maximum allowable stress [σy] of the catenary and / or wave-shaped riser armored steel wire to determine whether the maximum stress value exceeds the warning threshold and to determine the safety status of the riser; where L is the length of the riser under consideration;

[0046] When max(σy(t1))≤[σy], the riser is considered to be in a safe state;

[0047] When max(σy(t1))>[σy], the riser is considered to be in a dangerous state.

[0048] Step 3.6: Following Step 3.5, update and correct the maximum stress value and position max(σy(tn), L(tn)) of the latest time-based catenary and / or lazy wave type riser armored steel wire, and update and correct the maximum allowable stress value of the riser armored steel wire; compare max(σy(tn)) with the maximum allowable stress [σy] of the catenary and / or lazy wave type riser armored steel wire to determine whether the maximum stress value exceeds the warning threshold and to determine the safety status of the riser;

[0049] When max(σy(tn))≤[σy], the riser is considered to be in a safe state;

[0050] When max(σy(tn))>[σy], the riser is considered to be in a dangerous state.

[0051] Furthermore, in step 3.1, the control processing module, based on the collected signal source information from the hull and riser, substitutes the data into the force control equations for the catenary and / or wave-shaped riser to obtain the inclination angle, vertical force, axial force, and curvature of the entire catenary and / or wave-shaped riser. The calculation formula for the force control equations of the entire catenary and / or wave-shaped riser is as follows:

[0052]

[0053]

[0054]

[0055]

[0056]

[0057] Based on geometric relationships, the following governing equations can be given:

[0058]

[0059] T i =T h [cos θ+(ω i +a i +ε i q)sin θ]

[0060]

[0061] Among them, L i For the considered riser length, a i Let ε be the tangent at x = 0. i q 0 i q 1 i q 2 i q i α i β i ω i ξ i and η i The sum is a dimensionless quantity;

[0062] Among them, Th E represents the horizontal force acting on this section of the riser. i I i For bending stiffness, w is the force per unit length of the riser in the vertical direction, x is the projected length of the riser in the water depth direction, y is the projected length of the riser in the horizontal direction, and T is the bending stiffness. i For the riser to be subjected to axial force, M i θ is the bending moment of the riser, s is the length from the fixed point at the bottom of the riser to the calculated position of the riser, and θ is the inclination angle of the riser.

[0063] Furthermore, in step 3.2, the stress state at any point on the rectangular cross-section armored steel wire at any given time is calculated based on the inclination angle, vertical force, axial force, and curvature of the entire catenary and / or wave-shaped riser obtained in step 3.1. Specifically, this involves:

[0064] Substituting the inclination angle, vertical force, axial force, and curvature of the entire catenary and / or wave-shaped riser obtained in step 3.1 into the force equation of the riser armor wire, the maximum stress value and position of the catenary and / or wave-shaped riser armor wire at any time can be obtained.

[0065] The force equation for the riser armored steel wire is calculated as follows: Construct an orthogonal frame (n, b, t) on the spiral steel wire, and establish a local rectangular coordinate system (x2, x3) for the rectangular steel wire cross-section, where x2 is the major axis of the rectangle and x3 is the minor axis of the rectangle; when the riser is subjected to bending, by solving for the curvature changes in each direction of the rectangular cross-section, the force state at any point of the rectangular cross-section steel wire can be obtained:

[0066]

[0067] Where, σ b_n For the stress in the principal curvature direction of the rectangular cross section, σ b_b For the stress in the direction of curvature of the rectangular cross section, σ b_τ The torsional stress of the rectangular cross-section is given by φ, where φ is the wire winding angle, b is the wire width, β0 is the torsional coefficient of the cross-section, and E is the cross-sectional torsion coefficient. w Let Δk be the elastic modulus of the spiral steel wire. n ,Δk b Δτ represents the change in curvature of the rectangular cross-section of the helical steel wire in each direction, expressed as follows:

[0068]

[0069]

[0070] In the formula, GJ is the torsional stiffness of the cross section, and E... w I n and E w I bThese are the bending stiffnesses of the rectangular cross section about the x3 and x2 axes, respectively.

[0071] When the steel wire is subjected to a force of F w When subjected to axial tension, the stress state at any point on a rectangular cross-section steel wire can be expressed as:

[0072]

[0073] Where l is the length of the steel wire;

[0074] During the stretching and bending of the steel wire, the corners of the rectangular cross-section experience higher local stress and fail first. Therefore, the stress state at the corners needs to be considered, and its normal stress can be expressed as:

[0075] σ y =σ b_n +σ b_b +σ t_t +σ t_b

[0076] Where y represents the corner point number corresponding to the four corners of the rectangular section of the armored steel wire, y = 1, 2, 3, 4.

[0077] Furthermore, in the force equation of the riser armored steel wire, the vertical force w per unit length of the catenary riser can be fitted using a Mexican wavelet function to represent the relationship between the vertical force w per unit length and the riser length. This improves the monitoring accuracy of the inclination angle, vertical force, axial force, and linear curvature of the catenary riser during service, achieving an accuracy within 10%. The fitting function for w is as follows:

[0078]

[0079]

[0080]

[0081]

[0082]

[0083] Where p1-p7 are the variables in the equation, which can be represented as the lengths l1, l2, l3 of different riser sections. 1_1 ,l 1_2 l2, and the vertical force w per unit length of different riser sections p ,w f Implicit functions.

[0084] The vertical force *w* per unit length of a wave-type riser can be fitted using Mexican wavelet combined with a sigmoid function to determine the relationship between the vertical force *w* and the riser length. This improves the monitoring accuracy of the riser's tilt angle, vertical force, axial force, and curvature during service, achieving an accuracy within 10%. The fitting function for *w* is as follows:

[0085]

[0086]

[0087]

[0088]

[0089] w Con =w p

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099] Among them, p1-p 15 The variables in the equation are l1, l2, and l3, which can be represented as the lengths of different riser sections. 1_1 ,l 1_2 The vertical force w per unit length of l2, l3, l4, l5 and different riser sections p ,w f Implicit functions.

[0100] The system comprises a monitoring module, a transmission module, a control processing module, and an early warning module connected in sequence. The monitoring module collects signal source information from the hull and riser; this information is transmitted to the control processing module via the transmission module; the control processing module generates a preset system early warning threshold, updates and corrects the threshold based on the signal source information, calculates the maximum stress value of the armored steel wire, and determines whether it exceeds the early warning threshold, transmitting the result to the early warning module; the maximum stress value and position of the armored steel wire of the catenary and / or wave-shaped riser at any given time are also transmitted to the early warning module, and if the result exceeds the early warning threshold, an audible and / or visual warning is displayed. By indirectly measuring the signal source information of the hull and riser, real-time monitoring of riser stress safety can be achieved. The integrated and unified technical approach facilitates implementation and significantly improves the safety of catenary and wave-shaped risers during service.

[0101] Technical effects of the present invention:

[0102] 1. The monitoring system is easy to install. Real-time monitoring of the stress behavior of the armored steel wires of catenary and / or wave-shaped risers can be achieved by installing it on the hull and risers.

[0103] 2. The data processing module in the monitoring system uses the Mexican wavelet function to fit the w-curve of the catenary riser, which can improve the calculation accuracy and efficiency, and can improve the stress monitoring accuracy of the armored steel wire of the catenary riser to within 10%; the data processing module in the monitoring system uses the Mexican wavelet combined with the sigmoid function to fit the w-curve of the lazy wave riser, which can improve the calculation accuracy and efficiency, and can improve the stress monitoring accuracy of the armored steel wire of the lazy wave riser to within 10%.

[0104] 3. Integrate monitoring, transmission, control processing, and early warning modules to implement real-time and advance warning schemes. During the service of catenary and wave-shaped risers, when the stress on the riser armor wires is too high, more emphasis is placed on early warning and establishing a safe and robust monitoring model. In advance, it helps staff to reasonably adjust the hull position to reduce the stress extreme value of the riser armor wires, thereby ensuring the safe operation of the riser during its service. Attached Figure Description

[0105] The accompanying drawings illustrate various embodiments generally by way of example rather than limitation, and are used, together with the specification and claims, to explain embodiments of the invention. Where appropriate, the same reference numerals are used in all drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive embodiments of the apparatus or method.

[0106] Figure 1 This diagram illustrates the component deployment of the catenary and lazy wave riser monitoring system of the present invention;

[0107] Figure 2 This diagram illustrates the w-function fitting curves for the catenary and lazy wave risers of the present invention.

[0108] Figure 3 A geometrical schematic diagram of the flexible riser armor steel wire wound around the riser according to the present invention is shown;

[0109] Figure 4 A schematic diagram of the system modules of the present invention is shown.

[0110] Reference numerals: 1. Hull; 2. Riser section l6; 3. Riser section l5; 4. Riser section l4; 5. Riser section l3; 6. Riser section l2; 7. Inclination sensor A installed on the suspended riser section; 7a. Inclination sensor a installed on the suspended riser section; 8. Inclination sensor B installed on the suspended riser section; 9. Inclination sensor C installed on the suspended riser section; 10. Inclination sensor D installed on the suspended riser section; 11. Riser section l1; 12. Fitting curve of catenary riser w; 13. Fitting curve of lazy wave riser w; 14. Riser; 15. Spiral wound armored steel wire; 16. Corner point 1 of rectangular section of armored steel wire; 17. Corner point 2 of rectangular section of armored steel wire; 18. Corner point 3 of rectangular section of armored steel wire; 19. Corner point 4 of rectangular section of armored steel wire. Detailed Implementation

[0111] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0112] Implementation Case: Application of stress behavior monitoring for armored steel wires of flexible risers in marine nuclear power platforms

[0113] like Figure 1 The diagram shows the system component deployment. It illustrates the deployment locations of the catenary and wave-type riser monitoring modules. These modules are used to collect signal source information from the hull and risers, and include instruments for the two hulls and risers.

[0114] The instrumentation devices on the hull include an inertial navigation system (IMU) and a GPS navigation system installed on the hull;

[0115] The instrumentation devices on the hull obtain the distance Z from the riser joint to the seabed and the horizontal distance S from the riser joint to the seabed tree through the inertial navigation system (IMU) and the GPS navigation system installed on the hull.

[0116] The instrumentation devices of the catenary riser include an angle sensor A installed in the suspended section of the riser;

[0117] The instrument for the catenary riser obtains the tilt angle value θ1 of riser section I through tilt sensor A installed in the suspended section of the riser.

[0118] The instrumentation devices of the lazy wave riser include tilt sensor A, tilt sensor B, tilt sensor C and tilt sensor D installed on the suspended section of the riser section;

[0119] The instruments of the catenary riser obtain the tilt angle values ​​θ2, θ3, θ4 and θ5 of the suspended section of the riser through the tilt angle sensor A installed on the suspended section of the riser.

[0120] The data integration module uses acoustic transmission and / or wired transmission methods to transmit the collected signal source information from the hull and riser to the computer host of the ship at sea.

[0121] The processed data is displayed on a monitor using the display module, which facilitates real-time display of the stress behavior of the riser armored steel wire.

[0122] The control processing module includes a data processing module and a data calculation module;

[0123] The data processing module performs preliminary processing on the signal source information of the ship hull and riser by using abnormal data deletion and data selection methods; by designing the maximum threshold of each sensor, the data collected by the sensor that exceeds the maximum threshold is deleted, and the signal source information of the ship hull and riser collected by each sensor is sorted and arranged in chronological order to form a complete set of monitoring data at any time.

[0124] Based on the data processing module, the collected signal source information from the hull and riser is initially processed using methods such as abnormal data deletion and data selection. Based on the data calculation module, the processed initial signal source information data of the hull and riser is substituted into the force control equations for the catenary and / or wave-shaped riser to obtain the inclination angle, vertical force, axial force, and curvature of the entire catenary and / or wave-shaped riser. The calculation formulas for the force control equations of the entire catenary and / or wave-shaped riser are as follows:

[0125]

[0126]

[0127]

[0128]

[0129]

[0130] Based on geometric relationships, the following governing equations can be given:

[0131]

[0132] T i =T h [cos θ+(ω i +a i +ε i q)sin θ]

[0133]

[0134] Among them, L i For the considered riser length, a i Let ε be the tangent at x = 0. i q 0 i q 1 i q 2 i q i α i β i ω i ξ i and η i The sum is a dimensionless quantity;

[0135] Among them, T h E represents the horizontal force acting on this section of the riser. i I i For bending stiffness, w is the force per unit length of the riser in the vertical direction, x is the projected length of the riser in the water depth direction, y is the projected length of the riser in the horizontal direction, and T is the bending stiffness. i For the riser to be subjected to axial force, M i θ is the bending moment of the riser, s is the length from the fixed point at the bottom of the riser to the calculated position of the riser, and θ is the inclination angle of the riser.

[0136] Based on the data calculation module, the inclination angle, vertical force, axial force, and curvature of the entire catenary and wave-shaped riser at the initial moment are substituted into the force equation of the riser armor wire. This yields the maximum stress value and location of the catenary and / or wave-shaped riser armor wire at any given time. The calculation formula for the force equation of the riser armor wire is as follows: An orthogonal frame (n, b, t) is constructed on the helical wire, and a local rectangular coordinate system (x2, x3) is established for the rectangular wire cross-section, where x2 is the major axis of the rectangle and x3 is the minor axis. When the riser is bent, by solving for the curvature changes in each direction of the rectangular cross-section, the force state at any point on the rectangular cross-section wire can be obtained.

[0137]

[0138] Where, σ b_nFor the stress in the principal curvature direction of the rectangular cross section, σ b_b For the stress in the direction of curvature of the rectangular cross section, σ b_τ Let φ be the torsional stress in the rectangular cross-section, φ be the wire winding angle, b be the wire width, β0 be the torsional coefficient of the cross-section, and E be the torsional stress in the rectangular cross-section. w Let Δk be the elastic modulus of the spiral steel wire. n ,Δk b Δτ represents the change in curvature of the rectangular cross-section of the helical steel wire in each direction, expressed as follows:

[0139]

[0140]

[0141] In the formula, GJ is the torsional stiffness of the cross section, and E w I n and E w I b These are the bending stiffnesses of the rectangular cross section about the x3 and x2 axes, respectively.

[0142] When the steel wire is subjected to a force of F w When subjected to axial tension, the stress state at any point on a rectangular cross-section steel wire can be expressed as:

[0143]

[0144] Where l is the length of the steel wire;

[0145] During the stretching and bending of the steel wire, the corners of the rectangular cross-section experience higher local stress and fail first. Therefore, the stress state at the corners needs to be considered, and its normal stress can be expressed as:

[0146] σ y =σ b_n +σ b_b +σ t_t +σ t_b

[0147] Where y represents the corner point number corresponding to the four corners of the rectangular section of the armored steel wire (y = 1, 2, 3, 4).

[0148] Based on the data calculation module, in the force equation of the riser armored steel wire, the force w per unit length of the catenary riser in the vertical direction can be fitted using a Mexican wavelet function to represent the relationship between the force w per unit length of the riser and the riser length. This improves the monitoring accuracy of the inclination angle, vertical force, axial force, and linear curvature of the catenary riser during service, achieving an accuracy within 10%. The fitting function for w is as follows:

[0149]

[0150]

[0151]

[0152]

[0153]

[0154] Where p1-p7 are the variables in the equation, which can be represented as the lengths l1, l2, l3 of different riser sections. 1_1 ,l 1_2 l2, and the vertical force w per unit length of different riser sections p ,w f Implicit functions.

[0155] The vertical force *w* per unit length of a wave-type riser can be fitted using Mexican wavelet combined with a sigmoid function to determine the relationship between the vertical force *w* and the riser length. This improves the monitoring accuracy of the riser's tilt angle, vertical force, axial force, and curvature during service, achieving an accuracy within 10%. The fitting function for *w* is as follows:

[0156]

[0157]

[0158]

[0159]

[0160] w Con =w p

[0161]

[0162]

[0163]

[0164]

[0165]

[0166]

[0167]

[0168]

[0169]

[0170] Among them, p1-p 15 The variables in the equation are l1, l2, and l3, which can be represented as the lengths of different riser sections. 1_1 ,l 1_2 The vertical force w per unit length of l2, l3, l4, l5 and different riser sections p ,w f Implicit functions.

[0171] The maximum stress value and location (σmax) of the riser armor steel wire at the initial moment were calculated based on the data calculation module. y (t0),L(t0));

[0172] Based on the data processing module, max(σ) y (t0) and the maximum allowable stress of the catenary and wave-shaped riser armored steel wire [σ y By comparing the values, we can determine whether the maximum stress value exceeds the warning threshold and thus assess the safety status of the riser.

[0173] Based on the data processing module, the maximum stress value and position max(σy(t1),L(t1)) of the catenary and / or wave-shaped riser armored steel wire at time t1 are calculated, and the maximum allowable stress value of the riser armored steel wire is updated and corrected; max(σy(t1)) is compared with the maximum allowable stress [σy] of the catenary and / or wave-shaped riser armored steel wire to determine whether the maximum stress value exceeds the warning threshold and to determine the safety status of the riser; where L is the length of the riser considered.

[0174] Based on the data processing module, the latest time t is updated and corrected sequentially according to the steps described above. n The maximum stress value and location of the armored steel wire of the catenary and / or lazy wave type riser are calculated as max(σy(tn), L(tn)), and the maximum allowable stress value of the armored steel wire of the riser is updated and corrected. max(σy(tn)) is compared with the maximum allowable stress [σy] of the armored steel wire of the catenary and / or lazy wave type riser to determine whether the maximum stress value exceeds the warning threshold and to determine the safety status of the riser.

[0175] Based on the early warning module, the maximum stress value and location (max(σ)) of the catenary and / or lazy wave riser armored steel wire at any given time will be recorded. y (t n ),L(t n The data is transmitted to the early warning module. If the result exceeds the early warning threshold, the industrial control computer display module on the hull will start flashing, indicating that the current state is dangerous, and will play a pre-recorded voice audio signal to achieve the early warning function. At this time, the operator should stop the external transmission operation and adjust the position of the hull to ensure the safety of the riser.

[0176] Based on the early warning module, when max(σ) y (t n ))≤[σ y When the system is deemed to be in a safe state, the warning will be lifted, the display module will stop flashing, the current status will be displayed as safe, and the pre-recorded voice audio signal will stop playing.

[0177] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A system for monitoring the force behaviour of a marine flexible riser armour wire, characterised by, The riser monitoring module, the transmission module, the control processing module and the early warning module are connected in sequence. The monitoring module is used for collecting signal source information of the hull and the riser. The transmission module is used for transmitting the signal source information of the hull and the riser collected by the monitoring module to the control processing module. The control processing module is used for generating a preset system early warning threshold based on a preset riser safety index. The maximum stress value of the riser is updated and corrected according to the signal source information, and a corrected system threshold is generated synchronously. It is judged whether the maximum stress value of the riser armor wire exceeds the early warning threshold. The judgment result is transmitted to the early warning module. The early warning module is used for performing sound or / and image display early warning according to the judgment result of the control processing module. The control processing module comprises a data processing module and a data calculation module. The data processing module uses abnormal data deletion and data selection to preliminarily process the signal source information of the ship body and the riser collected; the maximum stress value of the riser is obtained, and the maximum stress value of the catenary or lazy wave riser armor wire at the time t is compared with the maximum allowable stress of the riser armor wire to determine whether the maximum stress value exceeds the early warning threshold and determine the safety state of the riser. n The data processing module uses abnormal data deletion and data selection to preliminarily process the signal source information of the ship body and the riser collected; the maximum stress value of the riser is obtained, and the maximum stress value of the catenary or lazy wave riser armor wire at the time t is compared with the maximum allowable stress of the riser armor wire to determine whether the maximum stress value exceeds the early warning threshold and determine the safety state of the riser. The data calculation module substitutes the collected signal source information of the hull and the riser into catenary riser stress control equations and lazy wave riser stress control equations respectively to obtain the inclination, vertical stress, axial stress and linear curvature of the whole catenary riser and / or lazy wave riser, and then calculates the stress state of any point of the rectangular cross-section armor wire at any moment to further obtain the maximum stress value and position of the riser armor wire at any moment.

2. A system for monitoring the behaviour of a flexible marine riser armour wire according to claim 1, characterised in that, The riser monitoring module comprises hull instrument devices, catenary riser instrument devices and lazy wave riser instrument devices. The hull instrument devices comprise an inertial navigation system and a GPS navigation system installed on the hull. The hull instrument devices obtain the distance Z from the riser joint to the seabed and the horizontal distance S from the riser joint to the subsea Christmas tree through the inertial navigation system IMU installed on the hull and the GPS navigation system installed on the hull. The catenary riser instrument devices comprise an inclination sensor A installed on the riser suspended section. The catenary riser instrument devices obtain the inclination value θ1 of the riser section I through the inclination sensor A installed on the riser suspended section. The lazy wave riser instrument devices comprise inclination sensors a, B, C and D installed on the riser suspended section. The lazy wave riser instrument devices obtain the inclination values θ2, θ3, θ4 and θ5 of the riser suspended section through the inclination sensors a, B, C and D installed on the riser suspended section.

3. A system for monitoring the behaviour of a steel wire under stress in a flexible marine riser according to claim 1, characterised in that, The transmission module comprises a data integration module and a display module. The data integration module transmits the collected signal source information of the hull and the riser to the computer host of the offshore hull by using acoustic transmission and / or wired transmission methods. The display module displays the processed data by using a display, and displays the stress behavior of the riser armor wire in real time.

4. A system for monitoring the behaviour of a steel wire under stress in a flexible marine riser according to claim 1, characterised in that, The data processing module performs preliminary processing on the information in the following manner: Catenary data processing: The maximum stress value of the catenary riser armor wire at time t0 is compared with the maximum allowable stress of the catenary riser armor wire, whether the maximum stress value exceeds the early warning threshold is judged, and the safety state of the riser is judged; the maximum stress value and position of the catenary riser armor wire at time t1 are calculated, and the maximum stress value of the corrected riser is updated; the maximum stress value of the catenary riser armor wire at time t1 is obtained and compared with the maximum allowable stress of the riser armor wire, whether the maximum stress value exceeds the early warning threshold is judged, and the safety state of the riser is judged; in this way, the maximum stress value of the riser is updated in turn according to the above steps, and the maximum stress value of the corrected riser at the latest time t n The maximum stress value of the catenary riser armor wire at time t0 is obtained and compared with the maximum allowable stress of the catenary riser armor wire, whether the maximum stress value exceeds the early warning threshold is judged, and the safety state of the riser is judged; the maximum stress value and position of the catenary riser armor wire at time t1 are calculated, and the maximum stress value of the corrected riser is updated; the maximum stress value of the catenary riser armor wire at time t1 is obtained and compared with the maximum allowable stress of the riser armor wire, whether the maximum stress value exceeds the early warning threshold is judged, and the safety state of the riser is judged; in this way, the maximum stress value of the riser is updated in turn according to the above steps, and the maximum stress value of the corrected riser at the latest time t n The maximum stress value of the catenary riser armor wire at time t0 is obtained and compared with the maximum allowable stress of the catenary riser armor wire, whether the maximum stress value exceeds the early warning threshold is judged, and the safety state of the riser is judged; the maximum stress value and position of the catenary riser armor wire at time t1 are calculated, and the maximum stress value of the corrected riser is updated; the maximum stress value of the catenary riser armor wire at time t1 is obtained and compared with the maximum allowable stress of the riser armor wire, whether the maximum stress value exceeds the early warning threshold is judged, and the safety state of the riser is judged; in this way, the maximum stress value of the riser is updated in turn according to the above steps, and the maximum stress value of the corrected riser at the latest time t Lazy wave data processing: The maximum stress value of the lazy wave type riser armored wire at the time t0 is compared with the maximum allowable stress of the lazy wave type riser armored wire, whether the maximum stress value exceeds the early warning threshold is judged, and the safety state of the riser is judged; the maximum stress value and position of the lazy wave type riser armored wire at the time t1 are calculated, and the maximum stress value of the corrected riser is updated; the maximum stress value of the lazy wave type riser armored wire at the time t1 is obtained and compared with the maximum allowable stress of the lazy wave type riser armored wire, whether the maximum stress value exceeds the early warning threshold is judged, and the safety state of the riser is judged; in this way, the maximum stress value of the riser is updated in turn according to the above steps, and the maximum stress value of the corrected riser at the latest time t n The maximum stress value of the lazy wave type riser armored wire at the time t0 is obtained and compared with the maximum allowable stress of the lazy wave type riser armored wire, whether the maximum stress value exceeds the early warning threshold is judged, and the safety state of the riser is judged; the maximum stress value and position of the lazy wave type riser armored wire at the time t1 are calculated, and the maximum stress value of the corrected riser is updated; the maximum stress value of the lazy wave type riser armored wire at the time t1 is obtained and compared with the maximum allowable stress of the lazy wave type riser armored wire, whether the maximum stress value exceeds the early warning threshold is judged, and the safety state of the riser is judged; in this way, the maximum stress value of the riser is updated in turn according to the above steps, and the maximum stress value of the corrected riser at the latest time t n The maximum stress value of the lazy wave type riser armored wire at the time t0 is obtained and compared with the maximum allowable stress of the lazy wave type riser armored wire, whether the maximum stress value exceeds the early warning threshold is judged, and the safety state of the riser is judged; the maximum stress value and position of the lazy wave type riser armored wire at the time t1 are calculated, and the maximum stress value of the corrected riser is updated; the maximum stress value of the lazy wave type riser armored wire at the time t1 is obtained and compared with the maximum allowable stress of the lazy wave type riser armored wire, whether the maximum stress value exceeds the early warning threshold is judged, and the safety state of the riser is judged; in this way, the maximum stress value of the 5. A system for monitoring the behaviour of a steel wire under stress in a flexible marine riser according to claim 1, characterised in that, The early warning module comprises a sound module and an image display module. The sound module is used for playing a safety early warning warning sound. The image display module is configured to display information of each monitoring quantity of the ship body, the inclination, the vertical force, the axial force and the linear curvature of the whole catenary riser and / or lazy wave riser at any moment, the stress state of any point of the rectangular cross-section armored steel wire at any moment, and the maximum stress value and position of the armored steel wire of the riser at any moment.

6. A method of operating a system for monitoring the behaviour of a steel wire under stress in a marine flexible riser according to claim 1, characterised in that, The method comprises the following steps: Step 1: collecting the signal source information of the ship body and the riser by the monitoring module; Step 2: transmitting the signal source information of the ship body and the riser collected in step 1 to the control processing module through the transmission module; Step 3: generating a preset system warning threshold based on a preset riser safety index by the control processing module; updating and correcting the maximum stress value of the riser according to the signal source information, and synchronously generating a corrected system threshold; determining whether the maximum stress value of the catenary riser and / or the lazy wave riser exceeds the warning threshold; and transmitting the determination result to the warning module; Step 4: transmitting the maximum stress value and position of the armored steel wire of the catenary riser and / or the lazy wave riser at any moment obtained in step 3 to the warning module, and performing sound and / or image display warning if the result exceeds the warning threshold; if the catenary riser and / or the lazy wave riser is determined to be in a dangerous state, the display module of the ship body will start to flash, display the current state as a dangerous state, and play a pre-recorded voice audio signal, thereby achieving a warning effect; Step 5, judging and canceling the early warning; when max(σ y (t n ))≤[σ y ], it is considered that the catenary riser and / or lazy wave riser is in a safe state, and the early warning is canceled. The step 3 comprises: Step 3.1: calculating the inclination, the vertical force, the axial force and the linear curvature of the whole catenary riser and / or lazy wave riser according to the signal source information of the ship body and the riser collected by the control processing module; Step 3.2: calculating the stress state of any point of the rectangular cross-section armored steel wire at any moment according to the inclination, the vertical force, the axial force and the linear curvature of the whole catenary riser and / or lazy wave riser obtained in step 3.1; Step 3.3: calculating the maximum stress value and position of the armored steel wire of the catenary riser and / or lazy wave riser at any moment; Step 3.4, compare the maximum stress value max(σ y (t0)) of the catenary and / or lazy wave riser armor wire at time t0 with the maximum allowable stress [σ y ] of the catenary and / or lazy wave riser armor wire, determine whether the maximum stress value exceeds the early warning threshold, and determine the safety state of the riser. wherein: max is the maximum value symbol; σ is the stress of the catenary and / or lazy wave riser armor wire; y is the four corner number of the rectangular cross section; taking the value of 1, 2, 3, 4; [σ y ] is the maximum allowable stress of the catenary and / or lazy wave riser armor wire, i.e. the maximum stress that the riser armor wire can withstand; When max(σ y (t0))≤[σ y ], the riser is considered in a safe condition; When max(σ y (t0))>[σ y ], the riser is considered in danger. Step 3.5, calculate the maximum stress value and position of the catenary and / or lazy wave type riser armor wire at t1 time max(σ y (t1), L(t1)) and update the maximum allowable stress value of the modified riser armor wire; compare max(σ y (t1)) with the maximum allowable stress [σ y ] of the catenary and / or lazy wave type riser armor wire, judge whether the maximum stress value exceeds the early warning threshold, and judge the safety state of the riser; wherein L is the length of the riser under consideration; When max(σ y (t1))≤[σ y ], the riser is considered to be in a safe state; When max(σ y (t1))>[σ y ], the riser is considered in danger. Step 3.6, update the latest time t according to step 3.5 in turn n Maximum stress value and position of catenary and / or lazy wave riser armor wire max(σ y (t n ), L(t n )) and update the maximum allowable stress value of the riser armor wire; compare max(σ y (t n )) with the maximum allowable stress [σ y ] of the catenary and / or lazy wave riser armor wire, judge whether the maximum stress value exceeds the early warning threshold, and judge the safety state of the riser; When max(σ y (t n ))≤[σ y ], the riser is considered to be in a safe state; When max(σ y (t n ))>[σ y ], the riser is considered in danger.

7. The method of working according to claim 6, characterized in that, In the step 3.1, the control processing module substitutes the signal source information of the ship body and the riser collected into the force control equation of the catenary riser and / or lazy wave riser to obtain the inclination, the vertical force, the axial force and the linear curvature of the whole catenary riser and / or lazy wave riser, and the force control equation of the whole catenary riser and / or lazy wave riser is calculated as follows: ； ； ； According to the geometric relationship, the following control equation is obtained: ； ； ； where L i is the length of the riser under consideration, a i is the tangent value at x = 0, e i , q 0 i , q 1 i , q 2 i , q i , a i , b i , w i , x i and h i are dimensionless quantities; where T h is the horizontal force on the riser, E i I i is the bending stiffness, w is the force per unit length of the riser in the vertical direction, x is the projected length of the riser in the water depth direction, y is the projected length of the riser in the horizontal direction, T i is the force on the riser in the axial direction, M i is the bending moment on the riser, s is the length of the riser from the fixed point at the bottom of the riser to the calculated location, and θ is the inclination of the riser.

8. The method of claim 6, wherein, In the step 3.2, the stress state of any point of the rectangular cross-section armored steel wire at any moment is calculated according to the inclination, the vertical force, the axial force and the linear curvature of the whole catenary riser and / or lazy wave riser obtained in step 3.1, and the specific calculation is as follows: The inclination, the vertical force, the axial force and the linear curvature of the whole catenary riser and / or lazy wave riser obtained in step 3.1 are substituted into the force equation of the armored steel wire of the riser to obtain the maximum stress value and position of the armored steel wire of the catenary riser and / or lazy wave riser at any moment; The force equation of the armored steel wire of the riser is calculated as follows: The orthogonal frame (n, b, t) is constructed on the helical steel wire, and the local rectangular coordinate system (x2, x3) is established on the rectangular steel wire section, wherein x2 is the long axis of the rectangle, and x3 is the short axis of the rectangle; When the riser is bent, the force state of an arbitrary point of the rectangular section steel wire is obtained by solving the curvature change of each direction of the rectangular section: ； wherein, is the stress in the principal curvature direction of the rectangular cross-section, is the stress in the secondary curvature direction of the rectangular cross-section, is the stress in the torsion direction of the rectangular cross-section, φ is the winding angle of the steel wire, b is the width of the steel wire, β0 is the cross-section torsion coefficient, E w is the elastic modulus of the helical steel wire, Δk n , Δk b and Δτ are the change amounts of the curvatures in each direction of the rectangular cross-section of the helical steel wire, and the expressions are as follows: ； ； where GJ is the torsional stiffness of the cross-section, E w I n and E w I b are the bending stiffnesses of the rectangular cross-section about the x3 and x2 axes, respectively. When the steel wire is subjected to an axial tension force F w The force state of an arbitrary point of the rectangular cross-section steel wire can be expressed as: ； Wherein l is the length of the steel wire; In the process of stretching and bending of the steel wire, the normal stress at the corner point of the rectangular section is represented as: ； Wherein y is the corner point number corresponding to the four corners of the rectangular section of the armored steel wire, y=1, 2, 3, 4.

9. The method of working according to claim 8, characterized in that, In the force equation of the riser armored steel wire: The force w of the unit length of the riser in the vertical direction of the catenary type riser, the fitting function of w is as follows: ； ； ； ； wherein p1, p2, p3, p4, p5, p6, p7 are variables of the equation, representing the length of different riser segments l1, l2, and the force in the vertical direction per unit length of different riser segments w1, w2 1_1 1_2 l2, and the force in the vertical direction per unit length of different riser segments w1, w2 p f implicit functions of​​ The force w of the unit length of the riser in the vertical direction of the lazy wave type riser, the fitting function of w is as follows: ； ； ； ； ； ； ； ； ； ； where p1 to p 15 are the variables of the equation, representing the lengths l1, l 1_1 , l 1_2 , l2, l3, l4, l5 of the different riser segments and the forces w p , w f per unit length of the different riser segments in the vertical direction as implicit functions.

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