Method for determining strength of pipe joint and related device

Abstract

The invention discloses a pipe joint strength determination method and a related device, and the method comprises the steps: obtaining an integrated model for a jacket foundation, and extracting a fatigue time-history load of the integrated model at a target type pipe joint according to a preset load working condition; and a pipe node model for the target type pipe node is obtained, and the geometric information of the target type pipe node included in the pipe node model is the same as that of the target type pipe node included in the integrated model, so that the stress condition of the target type pipe node can be finely analyzed. And according to the fatigue time-history load, determining the stress conditions of a plurality of pipe nodes included in the pipe node model under the plurality of simulation working conditions, and obtaining the strength of the target type of pipe nodes. Therefore, the fatigue time-history load, obtained based on the integrated model, of the target type pipe node can reflect the coupling effect of loads such as a wave load and a wind load, the pipe node model is analyzed based on the fatigue time-history load and is consistent with the actual physical world, potential safety hazards brought to a jacket are avoided, and the safety of a jacket foundation is improved.

Description

Technical Field

[0001] The invention relates to the technical field of wind power generation, and in particular to a method for determining the strength of a pipe node and a related device. Background Art

[0002] The pipe node is an important part of the jacket in the jacket foundation, and is mostly used in offshore areas with a water depth of more than 40m. As an important part of the offshore support structure, the jacket must withstand various complex dynamic loads and wave dynamic loads during the operation of wind turbines during its design life. On the other hand, its own complex welding structure, especially the welds, makes it more prone to fatigue failure. Therefore, the safety of the pipe node of the jacket is one of the important aspects of the safety of the offshore support structure.

[0003] In related technologies, the strength of the pipe nodes of the jacket is usually calculated using the distribution method. Taking fatigue strength as an example, the wave fatigue and wind turbine fatigue of the pipe nodes are calculated separately, and then the two are superimposed to obtain the final result. Among them, wind turbine fatigue is usually calculated using equivalent fatigue or Markov matrix, and wave fatigue is usually calculated using spectral fatigue method.

[0004] However, the superposition calculation method is inconsistent with the actual physical world, which makes it impossible to judge whether the final result is conservative or not, thus posing a safety hazard to the conductor rack. Summary of the invention

[0005] In view of the above problems, the present application provides a method for determining the strength of a pipe node and a related device, which can simultaneously consider the coupling effects of loads such as wave loads and wind loads to avoid safety hazards to the conductor frame.

[0006] Based on this, the embodiments of the present application disclose the following technical solutions:

[0007] In one aspect, an embodiment of the present application provides a method for determining the strength of a pipe node, the method comprising:

[0008] Acquire an integrated model for a jacket foundation, wherein the integrated model includes a target type pipe node, and the target type pipe node includes a plurality of pipe nodes;

[0009] Extracting fatigue time-history loads of the integrated model at the target type of pipe node according to a preset load condition;

[0010] Acquire a pipe node model for the target type pipe node, wherein the pipe node model is identical to geometric information of the target type pipe node included in the integrated model;

[0011] According to the fatigue time-history load, the stress conditions of the multiple tube nodes included in the tube node model under multiple simulated working conditions are determined to obtain the strength of the target type of tube nodes.

[0012] Optionally, the method further includes:

[0013] Constraining the node displacement included in the target tube node, and establishing load umbrellas on the tops of the respective tube nodes included in the other tube nodes, wherein the target tube node is one of the multiple tube nodes included in the target type tube node, and the other tube nodes are other tube nodes in the multiple tube nodes except the target tube node, and the load umbrellas are used to evenly distribute the point loads on the tube node model;

[0014] Establishing a first local coordinate system at the center of the payload parachute, wherein the first local coordinate system includes three mutually perpendicular coordinate axes, and different coordinate axes represent the forces on the payload parachute in different directions;

[0015] Unit forces or unit moments are applied to different coordinate axes included in the first local coordinate system to obtain a variety of simulation working conditions.

[0016] Optionally, unit forces or unit moments are applied to different coordinate axes included in the first local coordinate system to obtain multiple simulation conditions, including:

[0017] Applying a positive unit force, a negative unit force, a positive unit moment and a negative unit moment to the target coordinate axis included in the first local coordinate system respectively;

[0018] The three coordinate axes included in the first local coordinate system are respectively used as the target coordinate axes to obtain 36 unit working conditions;

[0019] According to the unit operating condition, the simulated operating condition is obtained.

[0020] Optionally, determining the stress conditions of multiple tube nodes included in the tube node model under multiple simulated working conditions according to the fatigue time history load to obtain the strength of the target type of tube node includes:

[0021] Establishing a second local coordinate system at the weld toe position of the pipe joint model, the second local coordinate system comprising a first coordinate axis, a second coordinate axis and a third coordinate axis, the first coordinate axis is parallel to the weld, the second coordinate axis is perpendicular to the weld, and the third coordinate axis is perpendicular to the first coordinate axis and the second coordinate axis;

[0022] Determine, according to the multiple simulation conditions, multiple stresses of the pipe node model in three coordinate axis directions in the second local coordinate system;

[0023] The strength of the target type of tubular node is determined according to the multiple stresses and the fatigue time history load.

[0024] Optionally, determining a plurality of stresses of the pipe node model in three coordinate axis directions in the second local coordinate system according to the plurality of simulation conditions includes:

[0025] Determining the type of weld included in the tubular node model according to welding specifications;

[0026] According to the type of the weld, extracting an extrapolated reference point corresponding to the weld;

[0027] According to the extrapolated reference point corresponding to the weld and the multiple simulated working conditions, multiple stresses in the three coordinate axis directions of the pipe node model in the second local coordinate system are determined.

[0028] Optionally, the method further includes:

[0029] Dividing the pipe node model into grids to obtain a pipe node grid model;

[0030] Applying shell elements on the surface of the tube node mesh model, wherein the shell elements are used to extract stress and strain information of the tube node at the weld;

[0031] The determining the strength of the target type of tubular node according to the multiple stresses and the fatigue time history load comprises:

[0032] Obtain the corresponding relationship between load and stress;

[0033] Based on the corresponding relationship between the load and the stress, the fatigue time history load and the multiple stresses are combined and calculated to obtain multiple stress components corresponding to the shell element respectively;

[0034] Determining stress-strain information according to the multiple stress components;

[0035] The strength of the target type of pipe node is determined according to the stress-strain information.

[0036] Optionally, determining the strength of the target type of pipe node according to the stress-strain information includes:

[0037] Obtain stress-life SN curve;

[0038] The fatigue strength of the target type of pipe node at the weld is determined according to the stress-strain information and the SN curve, wherein the SN curve is used to characterize the relationship between fatigue strength and fatigue life.

[0039] On the other hand, the present application provides a device for determining the strength of a pipe node, the device comprising: an acquisition unit, an extraction unit and a determination unit;

[0040] The acquisition unit is used to acquire an integrated model for the jacket foundation, wherein the integrated model includes a target type pipe node, and the target type pipe node includes a plurality of pipe nodes;

[0041] The extraction unit is used to extract the fatigue time history load of the integrated model at the target type pipe node according to a preset load condition;

[0042] The acquisition unit is further used to acquire a pipe node model for the target type pipe node, wherein the pipe node model has the same geometric information as the target type pipe node included in the integrated model;

[0043] The determination unit is used to determine the stress conditions of multiple tubular nodes included in the tubular node model under multiple simulated working conditions according to the fatigue time-history load, and obtain the strength of the target type of tubular nodes.

[0044] Optionally, the device further comprises a establishing unit and an applying unit;

[0045] The establishing unit is used for:

[0046] Constraining the node displacement included in the target tube node, and establishing load umbrellas on the tops of the respective tube nodes included in the other tube nodes, wherein the target tube node is one of the multiple tube nodes included in the target type tube node, and the other tube nodes are other tube nodes in the multiple tube nodes except the target tube node, and the load umbrellas are used to evenly distribute the point loads on the tube node model;

[0047] Establishing a first local coordinate system at the center of the payload parachute, wherein the first local coordinate system includes three mutually perpendicular coordinate axes, and different coordinate axes represent the forces on the payload parachute in different directions;

[0048] The applying unit is used to apply unit force or unit moment to different coordinate axes included in the first local coordinate system to obtain multiple simulation working conditions.

[0049] Optionally, the device further comprises an applying unit, configured to:

[0050] Applying a positive unit force, a negative unit force, a positive unit moment and a negative unit moment to the target coordinate axis included in the first local coordinate system respectively;

[0051] The three coordinate axes included in the first local coordinate system are respectively used as the target coordinate axes to obtain 36 unit working conditions;

[0052] According to the unit operating condition, the simulated operating condition is obtained.

[0053] Optionally, the determining unit is specifically configured to:

[0054] Establishing a second local coordinate system at the weld toe position of the pipe joint model, the second local coordinate system comprising a first coordinate axis, a second coordinate axis and a third coordinate axis, the first coordinate axis is parallel to the weld, the second coordinate axis is perpendicular to the weld, and the third coordinate axis is perpendicular to the first coordinate axis and the second coordinate axis;

[0055] Determine, according to the multiple simulation conditions, multiple stresses of the pipe node model in three coordinate axis directions in the second local coordinate system;

[0056] The strength of the target type of tubular node is determined according to the multiple stresses and the fatigue time history load.

[0057] Optionally, the determining unit is specifically configured to:

[0058] Determining the type of weld included in the tubular node model according to welding specifications;

[0059] According to the type of the weld, extracting an extrapolated reference point corresponding to the weld;

[0060] According to the extrapolated reference point corresponding to the weld and the multiple simulated working conditions, multiple stresses in the three coordinate axis directions of the pipe node model in the second local coordinate system are determined.

[0061] Optionally, the device further comprises a dividing unit and an applying unit;

[0062] The division unit is used to divide the pipe node model into grids to obtain a pipe node grid model;

[0063] The applying unit is used to apply shell elements on the surface of the pipe node mesh model, and the shell elements are used to extract stress and strain information of the pipe node at the weld;

[0064] The determining unit is specifically configured to:

[0065] Obtain the corresponding relationship between load and stress;

[0066] Based on the corresponding relationship between the load and the stress, the fatigue time history load and the multiple stresses are combined and calculated to obtain multiple stress components corresponding to the shell element respectively;

[0067] Determining stress-strain information according to the multiple stress components;

[0068] The strength of the target type of pipe node is determined according to the stress-strain information.

[0069] Optionally, the determining unit is specifically configured to:

[0070] Obtain stress-life SN curve;

[0071] The fatigue strength of the target type of pipe node at the weld is determined according to the stress-strain information and the SN curve, wherein the SN curve is used to characterize the relationship between fatigue strength and fatigue life.

[0072] In another aspect, the present application provides a computer device, the device comprising a processor and a memory:

[0073] The memory is used to store program codes and transmit the program codes to the processor;

[0074] The processor is used to execute the method described in the above aspects according to the instructions in the program code.

[0075] On the other hand, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium is used to store a computer program, and the computer program is used to execute the method described in the above aspects.

[0076] On the other hand, an embodiment of the present application provides a computer program product or a computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the method described in the above aspects.

[0077] The advantages of the above technical solution of this application are:

[0078] An integrated model for the jacket foundation is obtained, the integrated model includes a target type pipe node, and the target type pipe node includes multiple pipe nodes. According to the preset load condition, the fatigue time-history load of the integrated model at the target type pipe node is extracted, and the fatigue time-history load can reflect the influence of the coupling effect of loads such as wave load and wind load on the target type pipe node. Then, a pipe node model for the target type pipe node is obtained, and the pipe node model has the same geometric information as the target type pipe node included in the integrated model, so as to finely analyze the stress condition of the target type pipe node. Finally, according to the fatigue time-history load, the stress conditions of multiple pipe nodes included in the pipe node model under multiple simulation conditions are determined, and the strength of the target type pipe node is obtained. Therefore, the fatigue time-history load of the target type pipe node obtained based on the integrated model can reflect the coupling effect of loads such as wave load and wind load. The pipe node model is analyzed based on the fatigue time-history load, which is consistent with the actual physical world, avoiding safety hazards to the jacket and improving the safety of the jacket foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0080] Figure 1 A flow chart of a method for determining the strength of a pipe node provided in an embodiment of the present application;

[0081] Figure 2 A schematic diagram of a device for determining the strength of a pipe node provided in an embodiment of the present application;

[0082] Figure 3 A structural diagram of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0083] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0084] The foundation of the jacket usually consists of a jacket, a transition section and piles. Among them, the piles are welded twice with a diameter of about 2m-3m and driven into the seabed in advance. The jacket is a steel truss structure, which is welded from large-diameter low-alloy steel pipes. The jacket consists of main legs and cross braces. The main legs can be three-leg tower jackets or four-leg tower jackets. The main legs of the jacket are connected by horizontal cross braces and diagonal braces to transfer loads and strengthen the strength of the jacket. The transition section is a box beam structure located above the jacket, which serves to connect the tower and the jacket. Taking the jacket as an example, as an important part of the offshore support structure, the jacket has to withstand various complex dynamic loads and wave dynamic loads during the operation of the wind turbine during its 25-year design life. On the other hand, its own complex welding structure, especially the welds, makes it more prone to fatigue failure. Therefore, the safety of the pipe nodes of the jacket is one of the important contents of the safety of the offshore support structure.

[0085] In the related technology, the strength of the pipe nodes of the conductor rack is mostly calculated by the distribution method. Taking fatigue strength as an example, the wave fatigue and wind turbine fatigue of the pipe nodes are calculated separately, and then the two are superimposed to obtain the final result. Among them, wind turbine fatigue mostly uses equivalent fatigue or Markov matrix, and wave fatigue mostly uses spectral fatigue method. However, this superposition calculation method cannot take into account the coupling effect of waves and wind, and is inconsistent with the actual physical world, resulting in the inability to judge whether the final result is conservative or not, thus bringing safety hazards to the conductor rack.

[0086] In addition, the nominal stress method is often used to perform fatigue calculations on welded joints during fatigue calculations. For welds with regular shapes, especially welds with the normal direction perpendicular to the mud surface, this evaluation method is reasonable and effective, because the nominal stress calculated at this time is based on the size of the structure. However, for pipe node welds, since the load and the structural size direction of the weld are not consistent, the nominal stress obtained at this time cannot accurately reflect the stress distribution of the structure at this time. Specifically, the traditional nominal stress method is mostly based on a single load component when calculating the fatigue strength of the structure, and only considering a single load component, the fatigue calculation result may be biased to be less conservative. For offshore wind power, due to the influence of ice, waves and other conditions, the influence of loads such as Mx (load in one direction) and Mz (load in one direction) gradually increases. Therefore, for conservative considerations, when calculating the fatigue strength of the pipe node of the jacket, it is necessary to simultaneously consider the remaining load components except My (load in one direction). Therefore, using the nominal stress method to calculate the fatigue strength of the structure may cause the calculation result to be too conservative or too unconservative, which will bring safety hazards to the jacket.

[0087] Based on this, an embodiment of the present application provides a method for determining the strength of a pipe node and a related device. The fatigue time-history load of the target type of pipe node obtained based on the integrated model can reflect the coupling effect of loads such as wave loads and wind loads. The pipe node model is analyzed based on the fatigue time-history load, which is consistent with the actual physical world, avoids safety hazards to the conductor rack, and improves the safety of the conductor rack foundation.

[0088] Combine the following Figure 1 , a method for determining the strength of a pipe joint provided in an embodiment of the present application is introduced. Figure 1 , this figure is a flow chart of a method for determining the strength of a pipe node provided in an embodiment of the present application, and the method may include S101-S104.

[0089] S101: Obtain an integrated model for the jacket foundation.

[0090] In the related technologies, the strength of the pipe nodes of the jacket is mostly calculated by the distribution method. Taking fatigue strength as an example, the wave fatigue and wind turbine fatigue of the pipe nodes are calculated separately, and then the two are superimposed to obtain the final result. This method cannot take into account the coupling effect of waves and wind, and is inconsistent with the force of the pipe nodes in the actual physical world, resulting in an inability to judge whether the final result is conservative or not, thus bringing safety hazards to the jacket.

[0091] Based on this, the embodiment of the present application no longer models the pipe node separately, but considers that the pipe node will be affected by wave loads and wind loads, establishes an integrated model for the pipe frame foundation, and simulates the forces exerted on the wind turbine in the actual physical world based on the integrated model. The integrated model includes a target type pipe node, which is a type of pipe node including multiple pipe nodes, such as a K-type pipe node including 4 pipe nodes (the shape of this type of pipe node is like the letter K).

[0092] For example, an integrated model is established in the load simulation software, which includes the pipe frame foundation, tower and wind turbine, so that the internal force of the integrated model can be analyzed later to obtain the comprehensive force on the pipe node, thereby restoring the force on the pipe node in the actual physical world, rather than simply superimposing it.

[0093] S102: Extracting fatigue time-history loads of the integrated model at target type pipe nodes according to preset load conditions.

[0094] It is understandable that the target type of pipe node is subjected to different forces under different working conditions, and at different time points, the target type of pipe node is subjected to different forces. Therefore, based on the preset load conditions, the working conditions that the target type of pipe node may encounter in actual situations are simulated, such as the working conditions that the target type of pipe node will encounter are determined according to the IEC 61400 specification (a design specification for offshore wind turbines), that is, the preset load conditions. According to the preset load conditions, the fatigue time history load of the integrated model at the target type of pipe node is extracted, that is, the load that changes in size and direction over time.

[0095] Therefore, the fatigue time-history loads at the target type of pipe nodes extracted based on the integrated model can reflect the influence of load coupling such as wave load and wind load on the target type of pipe nodes, which is consistent with the forces exerted on the pipe nodes in the actual physical world, so that more accurate results can be obtained in subsequent analysis.

[0096] S103: Obtain a pipe node model for a pipe node of the target type.

[0097] The pipe node model has the same geometric information as the target type pipe nodes included in the integrated model, that is, the pipe node model is a part of the integrated model, so that only the target type pipe nodes can be analyzed in a targeted manner in the future, thereby reducing the amount of calculation and shortening the calculation time.

[0098] For example, a three-dimensional (3D) model for a target type of pipe node is established using computer aided design (CAD) software. The 3D model is a pipe node model, and the 3D model can correctly reflect the pipe node geometry information, even if it is the same as the geometry information of the target type of pipe node included in the integrated model. As a possible implementation, in order to facilitate subsequent analysis, the geometry information and spatial information of the 3D model can be made the same as the geometry information and spatial information of the target type of pipe node included in the integrated model.

[0099] S104: According to the fatigue time history load, the stress conditions of multiple tube nodes included in the tube node model under multiple simulation conditions are determined to obtain the strength of the target type of tube nodes.

[0100] As can be seen from the above, fatigue time-history load is a load that changes in size and direction over time. It can reflect whether the physical structure will fail under the alternating load. Therefore, the stress conditions of multiple pipe nodes included in the pipe node model under various simulated working conditions can be determined according to the fatigue time-history load, so as to obtain the strength of the target type of pipe node, so as to judge whether the pipe node will have problems due to excessive force under certain working conditions, thereby improving the safety of the jacket foundation.

[0101] It can be seen from the above technical solution that an integrated model for the jacket foundation is obtained, and the integrated model includes a target type pipe node, and the target type pipe node includes multiple pipe nodes. According to the preset load condition, the fatigue time-history load of the integrated model at the target type pipe node is extracted, and the fatigue time-history load can reflect the influence of the coupling effect of loads such as wave load and wind load on the target type pipe node. Then, a pipe node model for the target type pipe node is obtained, and the pipe node model has the same geometric information as the target type pipe node included in the integrated model, so as to finely analyze the stress condition of the target type pipe node. Finally, according to the fatigue time-history load, the stress conditions of multiple pipe nodes included in the pipe node model under multiple simulation conditions are determined, and the strength of the target type pipe node is obtained. Therefore, the fatigue time-history load of the target type pipe node obtained based on the integrated model can reflect the coupling effect of loads such as wave load and wind load. The pipe node model is analyzed based on the fatigue time-history load, which is consistent with the actual physical world, avoiding safety hazards to the jacket and improving the safety of the jacket foundation.

[0102] As can be seen from the foregoing, the simulation working condition is to simulate the actual working condition of the target type of pipe node. Since the real environment is complex and changeable, if a simulation working condition is established for each real environment, the workload is large. Based on this, the embodiment of the present application sets a variety of unit working conditions based on a variety of real environments, and obtains the required simulation working conditions through different combinations of one or more unit working conditions. The following is a specific description through S201-S203.

[0103] S201: constraining the node displacements included in the target tube node, and establishing load parachutes at the tops of the respective tube nodes included in the other tube nodes.

[0104] The target pipe node is a pipe node of the target type pipe node including multiple pipe nodes, and the other pipe nodes are other pipe nodes among the multiple pipe nodes except the target pipe node.

[0105] The node displacements included in the target tube node are constrained, and load umbrellas are established on the tops of the various tube nodes included in other tube nodes. That is, for the tube node model, one tube node in the target type tube node is constrained, and load umbrellas are established on the tops of the remaining tube nodes. The load umbrella is used to evenly distribute the point load on the tube node model so that the tube nodes included in the tube node model can simulate their stress conditions in the actual physical world.

[0106] As a possible implementation method, after building a three-dimensional model in CAD software, the three-dimensional model can be imported into finite element software to obtain a pipe node model. The pipe node model is meshed by finite element software to obtain a pipe node mesh model, and shell elements are applied to the surface of the pipe node mesh model so that the stress and strain information of the pipe node at the weld can be extracted by shell elements later. Taking the K-type pipe node as an example, it includes 4 pipe nodes, which can constrain the displacement of all nodes on the surface of pipe node 1, and load umbrellas are established on the tops of the remaining pipe nodes (i.e., pipe node 2, pipe node 3 and pipe node 4) for transferring loads. Therefore, the finite element method is used to calculate the pipe node structure of the jacket foundation, taking into account the influence of the actual complex shape of the structure on the calculation results, or in other words, considering the stress concentration effect caused by the complex structure.

[0107] S202: Establish a first local coordinate system at the center of the payload parachute.

[0108] The first local coordinate system includes three mutually perpendicular coordinate axes, and different coordinate axes represent the forces on the load parachute in different directions, such as the x-axis, y-axis and z-axis included in the spatial rectangular coordinate system.

[0109] S203: Apply unit force or unit moment to different coordinate axes included in the first local coordinate system to obtain multiple simulation working conditions.

[0110] The first local coordinate system includes three coordinate axes, and different coordinate axes represent the forces on the load parachute in different directions. Therefore, a force can be applied to each coordinate axis, which represents a force applied in one direction. Therefore, unit force or unit moment can be applied to different coordinate axes included in the first local coordinate system to obtain unit working conditions, thereby combining one or more unit working conditions to obtain multiple simulation working conditions.

[0111] Therefore, by establishing a unit operating condition, the influence of all load components on the structure is taken into account, and the influence of multiple load components on the fatigue strength of the structure can be considered at the same time, and the results are more comprehensive and accurate.

[0112] As a possible implementation method, a positive unit force, a reverse unit force, a positive unit moment and a negative unit moment are respectively applied to the target coordinate axis included in the first local coordinate system, and the target coordinate axis is one of the three coordinate axes included in the first local coordinate system. The three coordinate axes included in the first local coordinate system are respectively used as the target coordinate axes to obtain 36 unit working conditions, thereby obtaining the simulation working conditions according to the unit working conditions.

[0113] For example, a first local coordinate system is established at the center of the load parachute, and the direction of the first local coordinate system is consistent with the direction of the coordinate system in the load simulation software (such as Bladed). Unit force or unit moment can be applied to the position distribution of the load parachute corresponding to tube node 2, tube node 3 and tube node 4, respectively. For example, a positive unit force (which can be expressed as Fx, Fy and Fz), a reverse unit force (which can be expressed as -Fx, -Fy and Fz), a positive unit moment (which can be expressed as Mx, My and Mz) and a negative unit moment (which can be expressed as -Mx, -My and -Mz) are applied to the x-axis, and 3×12=36 unit working conditions are obtained.

[0114] Therefore, the calculation method of constraining a single node and loading the remaining nodes can make the current simulation closer to reality. By transferring the unit load to the structure through a load parachute, the influence of different foundation positions on the fatigue strength of the structure can be considered at the same time, and the result is more comprehensive.

[0115] As a possible implementation method, an embodiment of the present application provides a specific implementation method of S104, that is, according to the fatigue time-history load, determining the stress conditions of multiple pipe nodes included in the pipe node model under multiple simulated working conditions, and obtaining the specific implementation method of the strength of the target type of pipe node, which is specifically explained below through S1041-S1043.

[0116] S1041: Establish a second local coordinate system at the weld toe position of the pipe joint model.

[0117] The second local coordinate system includes a first coordinate axis, a second coordinate axis and a third coordinate axis. The first coordinate axis is parallel to the weld, the second coordinate axis is perpendicular to the weld, and the third coordinate axis is perpendicular to the first coordinate axis and the second coordinate axis.

[0118] For example, a second local coordinate system is established at the weld toe position of the pipe joint model. The second local coordinate system may be a spatial coordinate system including an x-axis, a y-axis and a z-axis, wherein the x-axis is parallel to the weld and the y-axis is perpendicular to the weld.

[0119] S1042: Determine multiple stresses of the pipe node model in three coordinate axis directions in the second local coordinate system according to multiple simulation conditions.

[0120] For example, in the second local coordinate system, the stress perpendicular to the weld is the first normal stress, which can be expressed as sy. The stress parallel to the weld is the second normal stress, which can be expressed as sx. The stress parallel to the weld is the shear stress, which can be expressed as sxy.

[0121] As a possible implementation method, the type of welds included in the pipe node model can be determined according to the welding specification; the extrapolated reference points corresponding to the welds can be extracted according to the type of welds; and the multiple stresses in the three coordinate axis directions of the pipe node model in the second local coordinate system can be determined according to the extrapolated reference points corresponding to the welds and multiple simulation conditions.

[0122] For example, if the current pipe node is welded based on the International Welding Association specification IIW, the weld toe type can be determined based on the provisions of IIW. If it is a type a weld (i.e., subsequent processing is performed along the surface of the structure), the extrapolated reference points are at 0.4t and 1t from the weld toe, respectively, and t is the thickness of the tower wall used for interpolation. If it is a type b weld (i.e., subsequent processing is performed along the edge of the structure), the extrapolated reference points are at 4mm, 8mm, and 12mm from the weld toe. The APDL program of Ansys (a finite element software) is used to extract the sx, sy, and sxy of the shell unit under different unit conditions, thereby obtaining multiple stresses in the three coordinate axis directions of the pipe node model in the second local coordinate system under different simulation conditions.

[0123] S1043: Determine the strength of the target type of tubular node based on multiple stresses and fatigue time history loads.

[0124] The strength of the target type of tubular joint is determined by fatigue time history load, or in other words, time series load is used for calculation instead of Markov matrix, which reduces the amount of calculation.

[0125] As a possible implementation method, the tube node model can be meshed first to obtain a tube node mesh model; shell elements are applied to the surface of the tube node mesh model so as to extract the stress and strain information of the tube node at the weld based on the shell elements. Then, the corresponding relationship between load and stress is obtained; based on the corresponding relationship between load and stress, the fatigue time history load and multiple stresses are combined and calculated to obtain multiple stress components corresponding to the shell elements; based on the multiple stress components, the stress and strain information is determined; based on the stress and strain information, the strength of the target type of tube node is determined.

[0126] For example, according to the specific relationship between load and stress, the fatigue time history load and the unit stress under the aforementioned 36 unit conditions (or the multiple stresses calculated in the second local coordinate system) are combined and calculated to obtain the three stress components of the shell element under the corresponding simulation conditions, which can be expressed as σ x , σ y and τ xy Then the critical plane method (CPA) is used to calculate the weld to obtain the stress spectrum at the weld toe, and the stress spectrum is subjected to rain flow statistics to obtain stress-strain information.

[0127] As a possible implementation method, a stress-life SN curve can be obtained; the fatigue strength of the target type of pipe node at the weld can be determined based on the stress-strain information and the SN curve. The SN curve is used to characterize the relationship between fatigue strength and fatigue life. For example, the Palmgren-Miner damage of the weld can be obtained by combining the SN curve, and the fatigue strength safety factor SRF of the weld can be obtained by taking the 25-year cumulative damage D=1 as a reference.

[0128] In addition to the method for determining the strength of a pipe node provided in the embodiment of the present application, a device for determining the strength of a pipe node is also provided. Figure 2 As shown, it includes: an acquisition unit 201, an extraction unit 202 and a determination unit 203;

[0129] The acquisition unit 201 is used to acquire an integrated model for a jacket foundation, wherein the integrated model includes a target type pipe node, and the target type pipe node includes a plurality of pipe nodes;

[0130] The extraction unit 202 is used to extract the fatigue time history load of the integrated model at the target type pipe node according to a preset load condition;

[0131] The acquisition unit 201 is further used to acquire a pipe node model for the target type pipe node, wherein the pipe node model has the same geometric information as the target type pipe node included in the integrated model;

[0132] The determination unit 203 is used to determine the stress conditions of the multiple tube nodes included in the tube node model under multiple simulation conditions according to the fatigue time history load, and obtain the strength of the target type of tube node.

[0133] It can be seen from the above technical solution that an integrated model for the jacket foundation is obtained, and the integrated model includes a target type pipe node, and the target type pipe node includes multiple pipe nodes. According to the preset load condition, the fatigue time-history load of the integrated model at the target type pipe node is extracted, and the fatigue time-history load can reflect the influence of the coupling effect of loads such as wave load and wind load on the target type pipe node. Then, a pipe node model for the target type pipe node is obtained, and the pipe node model has the same geometric information as the target type pipe node included in the integrated model, so as to finely analyze the stress condition of the target type pipe node. Finally, according to the fatigue time-history load, the stress conditions of multiple pipe nodes included in the pipe node model under multiple simulation conditions are determined, and the strength of the target type pipe node is obtained. Therefore, the fatigue time-history load of the target type pipe node obtained based on the integrated model can reflect the coupling effect of loads such as wave load and wind load. The pipe node model is analyzed based on the fatigue time-history load, which is consistent with the actual physical world, avoiding safety hazards to the jacket and improving the safety of the jacket foundation.

[0134] As a possible implementation, the device further includes an establishing unit and an applying unit;

[0135] The establishing unit is used for:

[0136] Constraining the node displacement included in the target tube node, and establishing load umbrellas on the tops of the respective tube nodes included in the other tube nodes, wherein the target tube node is one of the multiple tube nodes included in the target type tube node, and the other tube nodes are other tube nodes in the multiple tube nodes except the target tube node, and the load umbrellas are used to evenly distribute the point loads on the tube node model;

[0137] Establishing a first local coordinate system at the center of the payload parachute, wherein the first local coordinate system includes three mutually perpendicular coordinate axes, and different coordinate axes represent the forces on the payload parachute in different directions;

[0138] The applying unit is used to apply unit force or unit moment to different coordinate axes included in the first local coordinate system to obtain multiple simulation working conditions.

[0139] As a possible implementation, the device further includes an applying unit, which is used to:

[0140] Applying a positive unit force, a negative unit force, a positive unit moment and a negative unit moment to the target coordinate axis included in the first local coordinate system respectively;

[0141] The three coordinate axes included in the first local coordinate system are respectively used as the target coordinate axes to obtain 36 unit working conditions;

[0142] According to the unit operating condition, the simulated operating condition is obtained.

[0143] As a possible implementation manner, the determining unit 203 is specifically configured to:

[0144] Establishing a second local coordinate system at the weld toe position of the pipe joint model, the second local coordinate system comprising a first coordinate axis, a second coordinate axis and a third coordinate axis, the first coordinate axis is parallel to the weld, the second coordinate axis is perpendicular to the weld, and the third coordinate axis is perpendicular to the first coordinate axis and the second coordinate axis;

[0145] Determine, according to the multiple simulation conditions, multiple stresses of the pipe node model in three coordinate axis directions in the second local coordinate system;

[0146] The strength of the target type of tubular node is determined according to the multiple stresses and the fatigue time history load.

[0147] As a possible implementation manner, the determining unit 203 is specifically configured to:

[0148] Determining the type of weld included in the tubular node model according to welding specifications;

[0149] According to the type of the weld, extracting an extrapolated reference point corresponding to the weld;

[0150] According to the extrapolated reference point corresponding to the weld and the multiple simulated working conditions, multiple stresses in the three coordinate axis directions of the pipe node model in the second local coordinate system are determined.

[0151] As a possible implementation, the device further includes a dividing unit and an applying unit;

[0152] The division unit is used to divide the pipe node model into grids to obtain a pipe node grid model;

[0153] The applying unit is used to apply shell elements on the surface of the pipe node mesh model, and the shell elements are used to extract stress and strain information of the pipe node at the weld;

[0154] The determining unit 203 is specifically configured to:

[0155] Obtain the corresponding relationship between load and stress;

[0156] Based on the corresponding relationship between the load and the stress, the fatigue time history load and the multiple stresses are combined and calculated to obtain multiple stress components corresponding to the shell element respectively;

[0157] Determining stress-strain information according to the multiple stress components;

[0158] The strength of the target type of pipe node is determined according to the stress-strain information.

[0159] As a possible implementation manner, the determining unit 203 is specifically configured to:

[0160] Obtain stress-life SN curve;

[0161] The fatigue strength of the target type of pipe node at the weld is determined according to the stress-strain information and the SN curve, wherein the SN curve is used to characterize the relationship between fatigue strength and fatigue life.

[0162] The present application also provides a computer device, see Figure 3 , which shows a structural diagram of a computer device provided in an embodiment of the present application, such as Figure 3 As shown, the device includes a memory 310 and a processor 320:

[0163] The memory 310 is used to store program codes and transmit the program codes to the processor;

[0164] The processor 320 is used to execute any one of the methods for determining the strength of a pipe node provided in the above embodiments according to the instructions in the program code.

[0165] An embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium is used to store a computer program, wherein the computer program is used to execute any one of the methods for determining the strength of a pipe node provided in the above embodiments.

[0166] The embodiment of the present application also provides a computer program product or a computer program, which includes a computer instruction, and the computer instruction is stored in a computer-readable storage medium. The processor of the computer device reads the computer instruction from the computer-readable storage medium, and the processor executes the computer instruction, so that the computer device executes the method for determining the strength of a pipe node provided in various optional implementations of the above aspects.

[0167] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the system or device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0168] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0169] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0170] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0171] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining the strength of a tubular joint, characterized in that: The method comprises: Acquire an integrated model for a jacket foundation, wherein the integrated model includes a target type pipe node, and the target type pipe node includes a plurality of pipe nodes; Extracting fatigue time-history loads of the integrated model at the target type of pipe node according to a preset load condition; Acquire a pipe node model for the target type pipe node, wherein the pipe node model is identical to geometric information of the target type pipe node included in the integrated model; According to the fatigue time-history load, the stress conditions of the multiple tube nodes included in the tube node model under multiple simulated working conditions are determined to obtain the strength of the target type of tube nodes.

2. The method according to claim 1, characterized in that The method further comprises: Constraining the node displacement included in the target tube node, and establishing load umbrellas on the tops of the respective tube nodes included in the other tube nodes, wherein the target tube node is one of the multiple tube nodes included in the target type tube node, and the other tube nodes are other tube nodes in the multiple tube nodes except the target tube node, and the load umbrellas are used to evenly distribute the point loads on the tube node model; Establishing a first local coordinate system at the center of the payload parachute, wherein the first local coordinate system includes three mutually perpendicular coordinate axes, and different coordinate axes represent the forces on the payload parachute in different directions; Unit forces or unit moments are applied to different coordinate axes included in the first local coordinate system to obtain a variety of simulation working conditions.

3. The method according to claim 2, characterized in that The unit force or unit moment is applied to different coordinate axes included in the first local coordinate system to obtain a variety of simulation conditions, including: Applying a positive unit force, a negative unit force, a positive unit moment and a negative unit moment to the target coordinate axis included in the first local coordinate system respectively; The three coordinate axes included in the first local coordinate system are respectively used as the target coordinate axes to obtain 36 unit working conditions; According to the unit operating condition, the simulated operating condition is obtained.

4. The method according to claim 1, characterized in that: The step of determining the stress conditions of the plurality of pipe nodes included in the pipe node model under a plurality of simulated working conditions according to the fatigue time history load, and obtaining the strength of the pipe node of the target type, comprises: Establishing a second local coordinate system at the weld toe position of the pipe joint model, the second local coordinate system comprising a first coordinate axis, a second coordinate axis and a third coordinate axis, the first coordinate axis is parallel to the weld, the second coordinate axis is perpendicular to the weld, and the third coordinate axis is perpendicular to the first coordinate axis and the second coordinate axis; Determine, according to the multiple simulation conditions, multiple stresses of the pipe node model in three coordinate axis directions in the second local coordinate system; The strength of the target type of tubular node is determined according to the multiple stresses and the fatigue time history load.

5. The method according to claim 4, characterized in that Determining a plurality of stresses of the pipe node model in three coordinate axis directions in the second local coordinate system according to the plurality of simulation conditions includes: Determining the type of weld included in the tubular node model according to welding specifications; According to the type of the weld, extracting an extrapolated reference point corresponding to the weld; According to the extrapolated reference point corresponding to the weld and the multiple simulated working conditions, multiple stresses in the three coordinate axis directions of the pipe node model in the second local coordinate system are determined.

6. The method according to claim 4, characterized in that The method further comprises: Dividing the pipe node model into grids to obtain a pipe node grid model; Applying shell elements on the surface of the tube node mesh model, wherein the shell elements are used to extract stress and strain information of the tube node at the weld; The determining the strength of the target type of tubular node according to the multiple stresses and the fatigue time history load comprises: Obtain the corresponding relationship between load and stress; Based on the corresponding relationship between the load and the stress, the fatigue time history load and the multiple stresses are combined and calculated to obtain multiple stress components corresponding to the shell element respectively; Determining stress-strain information according to the multiple stress components; The strength of the target type of pipe node is determined according to the stress-strain information.

7. The method according to claim 6, characterized in that Determining the strength of the target type of pipe node according to the stress-strain information includes: Obtain stress-life SN curve; The fatigue strength of the target type of pipe node at the weld is determined according to the stress-strain information and the SN curve, wherein the SN curve is used to characterize the relationship between fatigue strength and fatigue life.

8. A device for determining the strength of a pipe joint, characterized in that: The device comprises: an acquisition unit, an extraction unit and a determination unit; The acquisition unit is used to acquire an integrated model for the jacket foundation, wherein the integrated model includes a target type pipe node, and the target type pipe node includes a plurality of pipe nodes; The extraction unit is used to extract the fatigue time history load of the integrated model at the target type pipe node according to a preset load condition; The acquisition unit is further used to acquire a pipe node model for the target type pipe node, wherein the pipe node model has the same geometric information as the target type pipe node included in the integrated model; The determination unit is used to determine the stress conditions of multiple tubular nodes included in the tubular node model under multiple simulated working conditions according to the fatigue time-history load, and obtain the strength of the target type of tubular nodes.

9. A computer device, characterized in that: The device comprises a processor and a memory: The memory is used to store program code and transmit the program code to the processor; The processor is used to execute the method according to any one of claims 1 to 7 according to the instructions in the program code.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium is used to store a computer program, and the computer program is used to execute the method according to any one of claims 1 to 7.

11. A computer program product, characterized in that The method comprises a computer program or an instruction; when the computer program or the instruction is executed by a processor, the method according to any one of claims 1 to 7 is executed.

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