A method for analyzing the force of a coastal net bag structure mooring rope

Abstract

The present application relates to the technical field of coastal engineering, and more particularly to a method for analyzing the force of mooring ropes of a coastal net structure, which solves the technical problems of long cycle and high cost in traditional force analysis relying on numerical simulation and physical model test, and comprises the following steps: collecting sea environment parameters and calculating wave parameters based on wave theory; determining the size and blocking condition of the net structure, calculating the blocking rate and underwater water-blocking area of the net; performing dimensionless processing on the flow and wave parameters, introducing a blocking rate correction coefficient determined according to the model test results, and calculating the maximum tension of the mooring rope connected to the pier or anchor block by using a fitting formula; and finally, performing safety evaluation of the net structure mooring system according to the calculation results. The present application can efficiently and at low cost estimate the maximum tension of the mooring rope of the net structure under complex dynamic conditions, and can provide quantitative basis for the design and safety check of coastal engineering.

Description

Technical Field

[0001] This invention relates to the field of coastal engineering technology, and in particular to a method for analyzing the stress on mooring ropes of a coastal net structure. Background Technology

[0002] In coastal nuclear power engineering and coastal protection engineering, flexible debris barriers (such as net structures) are often installed at the intake point to intercept marine organisms, floating debris, and other foreign objects, ensuring the safe operation of the water intake system. These flexible net structures operate under complex marine hydrodynamic environments (such as the combined effects of tides and waves), where the mooring ropes and connecting structures (piers, anchor blocks) bear dynamic loads and experience complex stress conditions. Improper design can lead to rope breakage, structural instability, and consequently, blockages or even shutdowns of the water intake system.

[0003] Currently, the industry mainly relies on numerical simulation or physical model testing for hydrodynamic load analysis and mooring rope stress analysis of such flexible net structures. While these two methods can obtain relatively accurate results, they generally suffer from problems such as long cycle time, high cost, and strong dependence on specialized software and test conditions. This makes it difficult to obtain stress estimates quickly and economically in the early design or scheme comparison stage, thus affecting design efficiency and the timeliness of scheme optimization.

[0004] Therefore, we propose a stress analysis method for mooring ropes in coastal net structures to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for analyzing the stress on mooring ropes of coastal net structures, which solves the technical problems of long cycle and high cost in traditional stress analysis relying on numerical simulation and physical model tests.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for analyzing the stress on mooring ropes of a coastal net structure includes the following steps: Step S1: Determination and Calculation of Key Environmental Parameters: Determine the basic environmental parameters of the target assembly sea area, including water depth d and design water flow velocity U. c The wave height H and period T are designed; then, the maximum water particle velocity U of the wave is calculated based on linear wave theory. w The wavelength L provides an input for subsequent quantification of the maximum tensile force of the mooring rope; Step S2, Determination and Calculation of Key Netting Structural Parameters: Determine the structural geometric parameters of the flexible netting, including the net opening width B. n Network port height and total length of the net Set the blockage length based on experience or risk assessment, and calculate the blockage rate. This parameter is defined as the blockage length. With the length of the net The ratio is used to quantify the degree of blockage; and based on the relative relationship between water depth and net height, the underwater area of ​​the net opening plane is calculated. ; Step S3, Dimensionless Processing: To eliminate the influence of physical dimensions and improve the universality and comparability of the formulas, the water flow velocity U is processed accordingly. c Maximum wave velocity U w The wavelength L was dimensionless, and the dimensionless water flow velocity was calculated. Dimensionless wave maximum water particle velocity and dimensionless wavelength This process introduces a correction factor that reflects the impact of blockage, determined by physical model experiments; Step S4, Maximum Tension Calculation: Substitute the dimensionless parameters obtained in Step S3 into the fitting formula established using multiple regression analysis based on physical model test data to calculate the maximum tension F of the mooring ropes connecting the pier or anchor block. lmax or F mlmax ; Step S5, Safety Assessment: Based on the calculated maximum tension of the mooring ropes, conduct a preliminary assessment of the structural safety and stability of the net structure mooring system (mooring ropes, pier structure, and anchor blocks) to provide quantitative basis for engineering design scheme comparison or safety verification.

[0007] Preferably, in step S1, the maximum wave velocity U is... w The calculation uses the linear wave theory formula: ; The mathematical expression for calculating wavelength L is: ; Where L represents wavelength, T represents period, d represents water depth, H represents wave height, and g represents gravitational acceleration.

[0008] Preferably, the blocking rate in step S2 is... The calculation formula is: ; in, The length of the blockage is determined by the direction from the end of the bag to the opening. This represents the total length of the net.

[0009] Preferably, the calculation of the underwater area of ​​the net opening in step S2 is based on water depth conditions: When the water depth d is less than the height of the mesh opening At that time, it was believed that the net was not completely submerged, so it was taken... ; When the water depth d is greater than or equal to the height of the mesh opening At that time, it was believed that the net was completely submerged, so it was taken out. ; in, The area of ​​the plane containing the opening of the net is submerged underwater, and d represents the water depth. Indicates the network port width. Indicates the network port height.

[0010] Preferably, the dimensionless water flow velocity in step S3 The calculation formula is: ; Where ε represents the clogging rate of the net structure, d represents the water depth, g represents the acceleration due to gravity, and U c Indicates the water flow velocity. This represents the coefficient that indicates the effect of the blockage rate on the water flow.

[0011] Preferably, in step S3, different formulas are used to calculate the dimensionless maximum water particle velocity of the waves for mooring ropes connecting different components. : For the maximum tension F of the mooring ropes connecting the piers lmax The calculation of its dimensionless wave velocity for: ; For the maximum tension F of the mooring rope connecting the anchor blocks mlmax The calculation of its dimensionless wave velocity for: ; Among them, U w This indicates the maximum velocity of water particles in the wave. The denot represents the blockage rate of the net structure, d represents the water depth, and g represents the acceleration due to gravity.

[0012] Preferably, the dimensionless wavelength in step S3 The calculations also distinguish between connecting components: For the maximum tension F of the mooring ropes connecting the piers lmax The calculation of its dimensionless wavelength for: ; For the maximum tension F of the mooring rope connecting the anchor blocks mlmax The calculation of its dimensionless wavelength for: ; Where L represents wavelength, The denot represents the blockage rate of the net structure, d represents the water depth, and g represents the acceleration due to gravity.

[0013] Preferably, the fitting formula in step S4 is the following multivariate high-order polynomial regression model: ; in, a is the maximum tension of the dimensionless mooring rope. c a w a wL b represents the regression coefficient. This represents the dimensionless velocity of water flow. This represents the maximum water particle velocity of a dimensionless wave. Indicates dimensionless wavelength; The maximum dimensional tension of a mooring rope is: ; in, This represents the maximum tension of the mooring ropes. This represents the maximum tension of the dimensionless mooring rope. For the density of water, Let d be the acceleration due to gravity and d be the water depth. This represents the area of ​​the plane containing the opening of the net underwater.

[0014] The present invention has at least the following beneficial effects: Achieving low-cost and efficient estimation of the maximum tension of mooring ropes in net structures: Traditional methods rely on complex numerical models and physical experiments, which are limited by long construction periods and high costs. This invention introduces a fitting formula based on physical model experimental data and regression analysis, combined with dimensionless processing and a blockage rate correction coefficient, to achieve rapid and low-cost calculation of the maximum tension of mooring ropes connecting piers and anchor blocks. This method can provide an estimate of the maximum tension of mooring ropes in the early design stage, greatly improving design efficiency, reducing early analysis costs, and providing an effective tool for rapid comparison and safety verification of engineering schemes.

[0015] The present invention also has the following beneficial effects: It possesses good versatility and engineering applicability: Through systematic dimensionless processing, the influence of physical dimensions is effectively eliminated, making the calculation formula highly universal and comparable, applicable to flexible net structures of different marine environments and structural dimensions. By introducing the blockage rate ε, the impact of different blockage conditions (such as marine organism aggregation and debris accumulation) on the mooring rope stress can be quantitatively assessed. As shown in Example 3, this method can conveniently perform multi-condition comparative analysis, clearly revealing the variation law between the blockage rate and the maximum tensile force, thereby providing direct quantitative basis for the reasonable selection of structural safety factors, the setting of early warning thresholds, or the design of cleaning and decontamination systems, supporting the refinement and optimization of engineering design. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating the stress analysis method for mooring ropes in a coastal net structure according to the present invention. Figure 2 This is a side view of the degree of blockage in the net-shaped mesh of the present invention; Figure 3 This is a top view showing the degree of blockage in the net-shaped mesh of the present invention; Figure 4 This is a front view of the degree of blockage in the net-shaped mesh of the present invention; Figure 5 This is a reference diagram showing the experimental conditions of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0019] Table 1 Summary of parameters in the fitting formula for the net bag ; Note: R represents the correlation coefficient in regression analysis. The closer to 1, the better the model fit. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of protection of this invention.

[0020] Example 1: Stress Analysis of Mooring Ropes on Connecting Piers under Sudden Working Conditions This embodiment uses a flexible debris-blocking net installed at the intake of a coastal nuclear power plant as an example to illustrate the specific implementation process of this method under marine organism outbreak conditions (with a high blockage rate).

[0021] Step S1: Determination and Calculation of Key Environmental Parameters: Collect basic environmental parameters for the target sea area: water depth d = 7.5 meters, design current velocity U. c = 0.5m / s, design wave height H = 1.0 m, period T = 10.0 s.

[0022] According to linear wave theory, the wavelength L is calculated as follows: ; The solution obtained by iteration is L = 81.40 m.

[0023] Calculate the maximum water particle velocity of the wave : =0.602m / s; Step S2: Determination and Calculation of Key Net Bag Structural Parameters: Mesh bag structural parameters: mesh opening width = 5.25 m, network port height = 10.0 m, total length of the net = 30m, set the blockage length = 8.0 m, under the unfavorable condition of complete blockage of the tail sump, the blockage rate is: .

[0024] Since the water depth d = 7.5 m < the height of the mesh opening = 10.0 m, the net structure is not completely submerged, the area of ​​the plane containing the net opening underwater: ; Step S3: Dimensionless processing: Dimensionless water flow velocity is calculated using F from Table 1. lmax Corresponding to β c = 3.0: 0.3538; Calculate the maximum water particle velocity of the dimensionless wave: 0.444 Calculate the dimensionless wavelength: ; Step S4: Calculate the dimensionless maximum tension of the mooring ropes connecting the pier: F in Table 1 lmaxSubstituting the corresponding regression analysis coefficients into the dimensionless tensile force formula: ; The maximum tension of the mooring ropes connecting the pier is: ; The estimation results of the model established in this invention are as follows: The physical model test result was 23.22 kN, a difference of 2%. The model estimation accuracy is high.

[0025] Step S5: Security Assessment Based on the calculated maximum tensile force F lmax = KN, combined with the design breaking force of the mooring ropes and the strength of the connecting components with the pier, can be used to conduct a safety check, and the safety of the net structure mooring system can be preliminarily assessed.

[0026] Example 2: Stress Analysis of Mooring Ropes Connecting Anchor Blocks under Typical Working Conditions This embodiment uses a flexible debris-blocking net installed at the intake of a water intake channel of a coastal nuclear power plant as an example to illustrate the specific implementation process of this method under typical operating conditions.

[0027] Step S1: Determination and Calculation of Key Environmental Parameters: Marine environmental parameters: d = 7.5 m, U c = 0.5 m / s, H = 1.5 m, T= 8.0s.

[0028] Calculations yield: L = 63.17m, U w =0.931m / s.

[0029] Step S2: Determination and Calculation of Key Net Bag Structural Parameters: = 5.25 m, = 10.0 m, = 30 m, blockage length = 4 m, then: ; Because d < , = 5.25 × 7.5 = 39.375 m 2 Step S3: Dimensionless processing: Dimensionless water flow velocity is calculated using F from Table 1. mlmax corresponding = 1.2: ; Calculate the maximum water particle velocity of the dimensionless wave: ; Calculate the dimensionless wavelength: ; Step S4: Calculate the dimensionless maximum tension of the mooring ropes connecting the pier: Substitute F into Table 1 above mlmax Corresponding coefficients: ; The maximum tension of the mooring rope connecting the anchor block is: ; The estimation results of the model established in this invention are as follows: The physical model test result was 15.8 kN, a difference of 3%. The model estimation accuracy is high.

[0030] Step S5: Security Assessment Calculated F mlmax In addition to verifying the design breaking force of the mooring ropes, the stability of the anchor block can also be further verified.

[0031] Example 3: Comparison and Design Optimization Analysis of Multiple Blockage Rate Operating Conditions This embodiment compares and analyzes the forces acting on the same net under different blockage rates, providing a basis for structural optimization in the design phase.

[0032] Step S1: Determination and Calculation of Key Environmental Parameters: Marine environmental parameters: d = 8 m, U c = 0.5 m / s, H = 3.0 m, T = 10 s.

[0033] The calculated values ​​are L = 83.72m, U w = 1.754 m / s.

[0034] Step S2: Determination and Calculation of Key Net Bag Structural Parameters: Net parameters: = 5.0m, = 9.0 m, = 28 m.

[0035] Calculate the following three blockage conditions respectively: Operating Condition A: = 0 m, ε = 0.000 Operating Condition B: = 4 m, ε = 0.143 Operating Condition C: = 8 m, ε = 0.286 Because d < , = 5 × 8 = 40 m 2 .

[0036] Steps S3-S4: Dimensionless calculation and calculation of the maximum tension of the mooring ropes connecting to the pier: Use F from Table 1 lmax Using the corresponding coefficients and formulas, the maximum tension F of the mooring ropes connecting the piers is calculated under three working conditions. lmax The results are summarized in Table 2: ; Table 2 Step S5: Safety Assessment and Design Recommendations As the blockage rate increases, the maximum tensile force of the mooring ropes connected to the piers also increases. Under operating condition C, the maximum tensile force exceeds 60 kN, significantly higher than under non-blockage conditions. It is recommended to increase the safety factor of the pier connection structure during the design phase, or to install a blockage warning and automatic cleaning system to address the high risk of blockage.

[0037] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A method for analyzing the forces acting on mooring ropes of a coastal net structure, characterized in that, Includes the following steps: Step S1: Determination and Calculation of Key Environmental Parameters: Collect basic environmental parameters of the target assembly sea area, including water depth d and design water flow velocity U. c The wave height H and period T are designed; then, the maximum water particle velocity U of the wave is calculated based on linear wave theory. w The wavelength L provides an input for subsequent quantification of the maximum tensile force of the mooring rope; Step S2, Determination and Calculation of Key Netting Structural Parameters: Determine the structural geometric parameters of the flexible netting, including the net opening width B. n Network port height and total length of the net Set the blockage length based on experience or risk assessment, and calculate the blockage rate. This parameter is defined as the blockage length. With the length of the net The ratio is used to quantify the degree of blockage; and based on the relative relationship between water depth and net height, the underwater area of ​​the net opening plane is calculated. ; Step S3, Dimensionless Processing: To eliminate the influence of physical dimensions and improve the universality and comparability of the formulas, the water flow velocity U is processed accordingly. c Maximum wave velocity U w The wavelength L was dimensionless, and the dimensionless water flow velocity was calculated. Dimensionless wave maximum water particle velocity and dimensionless wavelength This process introduces a correction factor that reflects the impact of blockage, determined by physical model experiments; Step S4, Maximum Tension Calculation: Substitute the dimensionless parameters obtained in Step S3 into the fitting formula established using multiple regression analysis based on physical model test data to calculate the maximum tension F of the mooring ropes connecting the pier or anchor block. lmax or F mlmax ; Step S5, Safety Assessment: Based on the calculated maximum tension of the mooring ropes, a preliminary assessment of the structural safety and stability of the net structure mooring system (mooring ropes, pier structure, and anchor blocks) is conducted to provide quantitative basis for engineering design scheme comparison or safety verification.

2. The method for analyzing the force on mooring ropes of a coastal net structure according to claim 1, characterized in that, In step S1, the maximum wave velocity U is... w The calculation uses the linear wave theory formula: ； The mathematical expression for calculating wavelength L is: ； Where L represents wavelength, T represents period, d represents water depth, H represents wave height, and g represents gravitational acceleration.

3. The method for analyzing the force on mooring ropes of a coastal net structure according to claim 1, characterized in that, The blocking rate in step S2 The calculation formula is: ； in, The length of the blockage is determined by the direction from the end of the bag to the opening. This represents the total length of the net.

4. The method for analyzing the force on mooring ropes of a coastal net structure according to claim 1, characterized in that, In step S2, the calculation of the underwater area of ​​the net opening is differentiated based on water depth conditions: When the water depth d is less than the height of the net At that time, it was believed that the net was not completely submerged, so it was taken... ; When the water depth d is greater than or equal to the height of the net At that time, it was believed that the net was completely submerged, so it was taken out. ; in, The area of ​​the plane containing the opening of the net underwater is represented by d, where d represents the water depth. Indicates the network port width. Indicates the network port height.

5. The method for analyzing the force on mooring ropes of a coastal net structure according to claim 1, characterized in that, The dimensionless water flow velocity in step S3 The calculation formula is: ； Where ε represents the blocking rate of the net structure, d represents the water depth, g represents the acceleration due to gravity, and U c Indicates the water flow velocity. This represents the coefficient of influence of the blocking rate on water flow.

6. The method for analyzing the force on mooring ropes of a coastal net structure according to claim 1, characterized in that, In step S3, different formulas are used to calculate the dimensionless maximum water particle velocity of the waves for mooring ropes connecting different components. : For the maximum tension F of the mooring ropes connecting the piers lmax The calculation of its dimensionless wave velocity for: ； For the maximum tension F of the mooring rope connecting the anchor blocks mlmax The calculation of its dimensionless wave velocity for: ； Among them, U w This indicates the maximum velocity of water particles in the wave. The denot represents the blockage rate of the net structure, d represents the water depth, and g represents the acceleration due to gravity.

7. The method for analyzing the force on mooring ropes of a coastal net structure according to claim 1, characterized in that, dimensionless wavelength in step S3 The calculations also distinguish between connecting components: For the maximum tension F of the mooring ropes connecting the piers lmax The calculation of its dimensionless wavelength for: ； For the maximum tension F of the mooring rope connecting the anchor blocks mlmax The calculation of its dimensionless wavelength for: ； in, Indicates wavelength. The denot represents the blockage rate of the net structure, d represents the water depth, and g represents the acceleration due to gravity.

8. The method for analyzing the force on mooring ropes of a coastal net structure according to claim 1, characterized in that, The fitting formula in step S4 is the following multivariate high-order polynomial regression model: ； in, a is the maximum tension of the dimensionless mooring rope. c a w a wL b represents the regression coefficient. This represents the dimensionless velocity of water flow. This represents the maximum water particle velocity of a dimensionless wave. Indicates dimensionless wavelength; The maximum dimensional tension of a mooring rope is: ； in, This represents the maximum tension of the mooring ropes. This represents the maximum tension of the dimensionless mooring rope. For the density of water, Let d be the acceleration due to gravity and d be the water depth. This represents the area of ​​the plane containing the opening of the net underwater.

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