A process optimization method for hoisting a large offshore wind power cylinder structure by a sling

Abstract

The application discloses a process optimization method for hoisting a large offshore wind power cylinder structure by a sling, and comprises the following steps: S1, for the hoisting process of the wind power cylinder, a mechanical model considering material properties and steel wire rope properties is established; S2, a theoretical sling wrap angle is calculated, the in-plane axial force, shear force and bending moment distribution of the cylinder in the sling hoisting process are obtained, and a risk position in the hoisting process is predicted through an actual wrap angle; S3, the radial displacement of each angle of the cylinder is calculated, and the absolute ovality and the relative ovality of the wind power cylinder are calculated according to the obtained radial displacement; S4, based on a longitudinal simplified mechanical model of the wind power cylinder hoisting, a theoretical sling hoisting position is calculated, and a calculation algorithm for accurately predicting a reasonable hoisting position is formed; and S5, a theoretical sling hoisting inclination angle is calculated, and the maximum inclination angle under the sling hoisting is determined. Through optimization of the sling hoisting scheme, the hoisting position, the hoisting wrap angle and the hoisting inclination angle are reasonably arranged, and the risks such as sliding and overturning possibly occurring in the hoisting process are effectively reduced.

Description

Technical Field

[0001] This invention belongs to the field of wind turbine casing hoisting, specifically involving a process optimization method for hoisting large offshore wind turbine casing structures. Background Technology

[0002] With the continuous development of marine engineering technology, wind turbine casing structures are increasingly widely used in offshore platforms, subsea pipelines, shipbuilding, and other fields. Due to their large size and heavy weight, safety, efficiency, and cost control during the hoisting of wind turbine casings have always been pressing challenges in the marine engineering field. "Sling hoisting" is a commonly used lifting method due to its ease of operation and low cost. However, with the expansion of project scale and the increase in the weight of the hoisted object, ensuring safety and stability during "sling hoisting" has become a critical issue that needs to be addressed.

[0003] "Hanging and hoisting" primarily utilizes steel wire ropes or other flexible materials wrapped around the surface of the wind turbine casing, lifting the object through friction and the design of the winding method. During this process, factors such as the hoisting position between the rope and the casing, the hoisting wrap angle and the rationality of the friction coefficient, as well as the shape and weight distribution of the casing, all directly affect the safety and stability of the hoisting. Studies have shown that during the hoisting of wind turbine casings, rope slippage and friction can lead to stress concentration, increasing the risk of the object slipping. Furthermore, due to the influence of wind loads, vibration, swaying, and other instability phenomena can easily occur during hoisting, even leading to more serious phenomena such as the casing slipping and overturning. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned shortcomings and provide an optimized process for hoisting and hauling large offshore wind turbine cylinder structures.

[0005] The objective of this invention is achieved through the following technical solution: an optimized process for hoisting and hauling large offshore wind turbine shroud structures, comprising,

[0006] S1. Establish a mechanical model that considers material properties and wire rope properties for the hoisting process of wind turbine casing;

[0007] S2. Calculate the theoretical wrap angle to obtain the axial force, shear force and bending moment distribution in the plane of the cylinder during the wrap lifting process. Based on the actual wrap angle, predict the risk location during the lifting process.

[0008] S3. Calculate the radial displacement of the cylinder at various angles, and calculate the absolute ellipticity and relative ellipticity of the wind turbine cylinder based on the obtained radial displacement.

[0009] S4. Based on the simplified longitudinal mechanical model of wind turbine cylinder hoisting, calculate the theoretical hoisting position and form a calculation algorithm to accurately predict the reasonable hoisting position;

[0010] S5. Based on the simplified mechanical model of the inclined hoisting of the wind turbine cylinder, calculate the theoretical hoisting tilt angle and determine the maximum tilt angle under the hoisting.

[0011] A further improvement of the present invention is that: in step S1, Q345R steel is selected as the cylinder material, and without considering the safety factor, the tension of the wire rope is: (1);

[0012] In formula (1): T is the tension in each wire rope; The maximum lifting weight of the lifting equipment is n; n is the number of wire ropes used, using two strands in one bend, with two lifting points, which is equivalent to 4 wire ropes. The angle between the wire rope and the horizontal plane of the hoisted load;

[0013] In the selection of wire rope, the tensile force P of the wire rope is calculated using the following formula: (2);

[0014] In formula (2): k is the safety factor for the use of wire rope, and the sling is made of 6x37 type wire rope in the form of a ring or 8 strands.

[0015] A further improvement of the present invention is that: in step S2, the cylindrical structure is twice statically indeterminate, and the axial force of the curved beam... Shear force and bending moment Based on the boundary conditions: (3);

[0016] In formula (3), , , These are the axial force, shear force, and bending moment of the curved beam, respectively. , , These are the axial force, shear force, and bending moment caused by gravity within the cylindrical surface, respectively. , , The axial force, shear force, and bending moment are caused by the uniformly distributed force generated by the wire rope pulling the cylinder. , , The axial force, shear force, and bending moment caused by the tension in the wire rope; , , The axial force, shear force, and bending moment are caused by symmetrical pressure within the cylindrical surface. , , The axial force, shear force, and bending moment are caused by the symmetrical bending moment within the cylindrical surface.

[0017] The solution is obtained using the unit force method from mechanics of materials. A horizontal axial unit force is applied at point A at the end of the curved beam. Unit bending moment in the axial direction Establish the force method equations for a second-order statically indeterminate curved beam. (4);

[0018] In formula (4), unit force When acting alone, point A along Displacement caused by direction; unit force and unit bending moment When both are acting simultaneously, point A along... Displacement caused by direction; unit bending moment When acting alone, point A along Displacement caused by direction; , , In unit force When the uniformly distributed force of the sling, the weight of the cylinder, and the tension of the wire rope act individually, point A along... Displacement caused by direction; , , To be respectively at unit bending moment When the uniformly distributed force of the sling, the weight of the cylinder, and the tension of the wire rope act individually, point A along... Displacement caused by direction;

[0019] Calculate formula (4) and substitute the result into formula (3) to solve for the distribution of axial force, shear force and bending moment in the plane of the cylinder during the hoisting process. In the actual hoisting project, substitute the actual parameters to obtain the distribution of axial force, shear force and bending moment in the plane of the cylinder during the hoisting process. Thus, the risk position in the hoisting process can be predicted by the actual wrap angle.

[0020] A further improvement of the present invention is that, in step S3, the formula for calculating the radial displacement of the cylinder at various angles is as follows:

[0021] when When the radial displacement equation is: (5);

[0022] when When the radial displacement equation is: (6);

[0023] In formulas (5) and (6): , , and , , These are the angles under a unit radial force. The axial force, shear force, and bending moment on the left and right sides, with the expression for the internal forces of the curved beam under a unit radial force is as follows:

[0024] (7);

[0025] In formula (7): , , These represent the axial force, shear force, and bending moment of the curved beam under unit radial force.

[0026] Based on the obtained radial displacement, the formulas for calculating the absolute and relative ellipticity of the wind turbine casing during the hoisting process are as follows: (8);

[0027] In formula (8): Absolute ellipticity; Relative ellipticity; and These are the maximum and minimum deformation diameters of the wind turbine casing, respectively. It is the inner diameter of the cross section.

[0028] A further improvement of the present invention is that, in step S4, according to the principles of mechanics of materials, when the cylinder as a whole is subjected to a uniformly distributed load of its own weight, it is simplified to a simple mechanical cantilever beam model, and the following formula can be obtained through calculation: (9);

[0029] In formula (9): R A The force is the force at the left fulcrum; R B q is the force at the right fulcrum; l is the uniformly distributed load of the cylinder's self-weight; a is the total length of the cylinder; and a is the distance from the fulcrum to both ends.

[0030] The bending moment at any point can also be calculated using the following formula: (10);

[0031] In formula (10): M is the bending moment;

[0032] And axial stress for: (11);

[0033] In formula (11): W is the section modulus for bending resistance;

[0034] Based on the above calculation formula, the maximum positive bending moment occurs at the mid-span of the cylinder, and the bending moment is... The maximum negative bending moment occurs at both the left and right suspension points, with a value of [value missing]. According to the optimization requirement of minimizing maximum bending moment, the maximum positive bending moment should be equal to the maximum negative bending moment, that is... , the best position for hoisting under the strength requirement can be determined as the distance from the end of the position, at this time the maximum bending moment value in the cylinder , the longitudinal bending moment is minimized, the bending normal stress is minimized, and it is the best strength hoisting design position;

[0035] The maximum positive deflection occurs at the mid-span of the cylinder, and the maximum negative deflection occurs at both ends of the cylinder. The deflections are respectively and . To ensure the optimization requirement of minimizing the maximum deflection, the values at the location where the maximum deflection occurs should be equal, that is . The best position under the deflection requirement is determined as , at this time the deflection is the smallest, and it is the best stiffness hoisting design position. Therefore, to ensure the best strength and deflection of the cylinder, in actual hoisting, the best hoisting position is selected to be between and . In the project, the position from the head is selected as the hoisting position.

[0036] A further improvement of the present invention is that in step S5, for two symmetric steel wires, the relationship between the tensile forces of the two steel wires and the position of the center of gravity of the inclined cylinder is as follows: (12);

[0037] In formula (12): l1 is the distance from the center of gravity of the inclined cylinder to the left hoisting point; l2 is the distance from the center of gravity of the inclined cylinder to the right hoisting point; R is the radius of the cylinder, is the distance from the fulcrum to both ends, is the inclination angle of the cylinder. When the cylinder is in a balanced state during hoisting, the equilibrium equation is:

[0038] (13);

[0039] In formula (13), is the total weight of the cylinder. Combining formula (13) and arranging, we can get: (14);

[0040] A further improvement of the present invention is that when there is an inclination during hoisting, T1 > T2. At this time, the tensile force of the steel wire at the lower end is greater, and it is necessary to satisfy T1 < F to ensure that the hoisting load of this steel wire is within the safe range; when the tensile force received by the steel wire at the upper end gradually decreases until the tensile force drops to 0, at this time, the cylinder overturns. Therefore, when the radius R of the cylinder is larger, the safe range of the inclination angle is smaller, and it is easier for the cylinder to overturn;

[0041] During hoisting, the pressure F N between the steel wire and the cylinder and the frictional force F S1The expression is: (15);

[0042] To prevent the drum from slipping, the pressure and friction between the wire rope and the drum must satisfy the following relationship: (16);

[0043] In formula (16): f is the coefficient of friction when the wire rope slides against the drum, therefore The range of values ​​is .

[0044] Compared with the prior art, the present invention has the following advantages:

[0045] 1. This invention, focusing on the dynamic simulation and optimization of the hoisting process for wind turbine casings, has significant practical implications and application value. By constructing a precise model and combining it with advanced simulation technology, various situations during the hoisting process can be simulated, providing a scientific basis for optimizing the hoisting scheme. Optimizing the hoisting scheme allows for the rational arrangement of hoisting positions, hoisting wrap angles, and hoisting inclination angles, effectively reducing risks such as slippage and overturning that may occur during hoisting. This invention not only helps solve current hoisting challenges in the marine engineering field but also provides valuable reference and guidance for future marine engineering technology development. Continuous optimization of hoisting schemes and technical methods can promote continuous innovation and progress in marine engineering technology.

[0046] 2. This invention identifies high-risk areas during hoisting by calculating the distribution of axial force, shear force, and bending moment under theoretical and actual wrap angles, effectively preventing localized damage or slippage accidents caused by stress concentration. It introduces calculation and evaluation methods for absolute and relative ellipticity to ensure the shape stability of the cylinder during hoisting, avoiding subsequent installation or usage problems caused by excessive deformation. Through simplified longitudinal and inclined hoisting models, the optimal hoisting position and maximum safe tilt angle are calculated, ensuring both strength and stiffness requirements while considering practical feasibility, significantly improving hoisting safety and efficiency. Through tribological analysis and tilt angle limitation calculations, it effectively suppresses swaying and sliding phenomena caused by wind loads, reducing the risk of cylinder overturning, making it particularly suitable for hoisting operations in complex environments such as marine engineering. Attached Figure Description

[0047] Figure 1 This is a simplified force diagram of the cylinder in this invention.

[0048] Figure 2 This is a simplified diagram of the local forces acting on the cylinder in this invention.

[0049] Figure 3 This is a simplified diagram of the forces acting on the curved beam under radial unit force in this invention.

[0050] Figure 4This is a longitudinal force diagram of the cylinder in this invention.

[0051] Figure 5 This is a force diagram showing the cylinder being tilted during hoisting in this invention.

[0052] Figure 6 The in-plane bending moment of the cylinder in this invention varies with different angles. The changes.

[0053] Figure 7 This is a diagram showing the deformation result of the cylinder when the half-wrap angle is 90° in this invention.

[0054] Figure 8 This is a diagram showing the deformation result of the cylinder when the half-wrap angle is 120° in this invention.

[0055] Figure 9 This is a diagram showing the deformation result of the cylinder when the half-wrap angle is 135° in this invention. Detailed Implementation

[0056] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments and accompanying drawings. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0057] An optimized process for hoisting and hauling large offshore wind turbine hull structures includes,

[0058] S1. Establish a mechanical model that considers material properties and wire rope properties for the hoisting process of wind turbine casing;

[0059] S2. Calculate the theoretical wrap angle to obtain the axial force, shear force and bending moment distribution in the plane of the cylinder during the wrap lifting process. Based on the actual wrap angle, predict the risk location during the lifting process.

[0060] S3. Calculate the radial displacement of the cylinder at various angles, and calculate the absolute ellipticity and relative ellipticity of the wind turbine cylinder based on the obtained radial displacement.

[0061] S4. Based on the simplified longitudinal mechanical model of wind turbine cylinder hoisting, calculate the theoretical hoisting position and form a calculation algorithm to accurately predict the reasonable hoisting position;

[0062] S5. Based on the simplified mechanical model of the inclined hoisting of the wind turbine cylinder, calculate the theoretical hoisting tilt angle and determine the maximum tilt angle under the hoisting.

[0063] In step S1, the material selection for the wind turbine casing must consider various factors. Based on the hoisting and operating conditions requirements mentioned in this invention, the wind turbine casing needs to meet requirements such as good tensile strength, impact resistance, and corrosion resistance. Simultaneously, it also needs to comprehensively consider multiple conditions such as strength, stability, processability and manufacturability, service life, and maintenance. Therefore, to ensure that the selected material can meet the actual needs of the casing and the operating environment, Q345R steel is chosen as the casing material. To simplify the stress analysis of the casing, it is assumed that the hoisting rope is long and vertical. This ensures that the stability, strength, and stiffness of the structure closely approximate the actual situation, guaranteeing the validity of the analysis results and providing guidance for practical engineering.

[0064] Without considering a safety factor, the tension in the wire rope is: (1);

[0065] In formula (1): T is the tension in each wire rope; The maximum lifting weight of the lifting equipment is n; n is the number of wire ropes used, using two strands in one bend, with two lifting points, which is equivalent to 4 wire ropes. The angle between the wire rope and the horizontal plane of the hoisted load;

[0066] In the selection of wire rope, the tensile force P of the wire rope is calculated using the following formula: (2);

[0067] In formula (2): k is the safety factor for the use of wire rope, and the sling is made of 6x37 type wire rope in the form of a ring or 8 strands.

[0068] In step S2, the wrap angle during cylinder hoisting plays a crucial role, directly affecting the stability and safety of the hoisting process. The wrap angle refers to the angle formed when the hoisting rope or sling contacts the cylinder surface. A larger wrap angle means a larger and more evenly distributed contact area between the hoisting rope or sling and the cylinder, thus helping to reduce stress and deformation of the cylinder during hoisting. Based on mechanical principles, this can be simplified into a curved beam model for analysis, allowing calculations to determine the stress on the cylinder under different wrap angles.

[0069] like Figure 1 As shown, the inner diameter of the cylinder ,thickness The specific gravity of the steel used is The elastic modulus and Poisson's ratio are respectively and (shearing model) The steel wire rope forms a semi-wrapped angle when it contacts the cylinder. The uniform self-weight load of the cylinder is , and Let x be a set of symmetrical pressures in the x-direction. and It is a set of symmetrical bending moments.

[0070] The cylindrical structure is twice statically indeterminate. Figure 2 In the coordinate system, the axial force of the curved beam Shear force and bending moment Based on the boundary conditions: (3);

[0071] In formula (3), , , These are the axial force, shear force, and bending moment of the curved beam, respectively. , , These are the axial force, shear force, and bending moment caused by gravity within the cylindrical surface, respectively. , , The axial force, shear force, and bending moment are caused by the uniformly distributed force generated by the wire rope pulling the cylinder. , , The axial force, shear force, and bending moment caused by the tension in the wire rope; , , The axial force, shear force, and bending moment are caused by symmetrical pressure within the cylindrical surface. , , The axial force, shear force, and bending moment are caused by the symmetrical bending moment within the cylindrical surface.

[0072] The solution is obtained using the unit force method from mechanics of materials. A horizontal axial unit force is applied at point A at the end of the curved beam. Unit bending moment in the axial direction Establish the force method equations for a second-order statically indeterminate curved beam. (4);

[0073] In formula (4), unit force When acting alone, point A along Displacement caused by direction; unit force and unit bending moment When both are acting simultaneously, point A along... Displacement caused by direction; unit bending moment When acting alone, point A along Displacement caused by direction; , , In unit force When the uniformly distributed force of the sling, the weight of the cylinder, and the tension of the wire rope act individually, point A along... Displacement caused by direction; , , To be respectively at unit bending moment When the uniformly distributed force of the sling, the weight of the cylinder, and the tension of the wire rope act individually, point A along... Displacement caused by direction;

[0074] Calculate formula (4) and substitute the result into formula (3) to solve for the distribution of axial force, shear force and bending moment in the plane of the cylinder during the hoisting process. In the actual hoisting project, substitute the actual parameters to obtain the distribution of axial force, shear force and bending moment in the plane of the cylinder during the hoisting process. Thus, the risk position in the hoisting process can be predicted by the actual wrap angle.

[0075] In step S3, the force method is used to solve for the analytical expression of deformation at any position of the curved beam. Figure 3 The figure shows a simplified model of a curved beam with hinged ends. Radial force of curved beam The angle corresponding to the action.

[0076] The formulas for calculating the radial displacement of the cylinder at various angles are shown below.

[0077] when When the radial displacement equation is: (5);

[0078] when When the radial displacement equation is: (6);

[0079] In formulas (5) and (6): , , and , , These are the angles under a unit radial force. The axial force, shear force, and bending moment on the left and right sides, with the expression for the internal forces of the curved beam under a unit radial force is as follows:

[0080] (7);

[0081] In formula (7): , , These represent the axial force, shear force, and bending moment of the curved beam under unit radial force.

[0082] Based on the obtained radial displacement, the formulas for calculating the absolute and relative ellipticity of the wind turbine casing during the hoisting process are as follows: (8);

[0083] In formula (8): Absolute ellipticity; Relative ellipticity; and These are the maximum and minimum deformation diameters of the wind turbine casing, respectively. It is the inner diameter of the cross section.

[0084] The standard GB / T 150.1-2011 specifies that the ellipticity of the pressure vessel shell should generally not exceed 1%-2%. In practical applications, if strength requirements are stringent, a wrap angle that meets the strength requirements should be used; if stiffness requirements are stringent, a wrap angle that meets the stiffness requirements should be used. This selection method can be flexibly adjusted according to specific working conditions and design needs to ensure the safety and reliability of the sling hoisting system.

[0085] In step S4, according to the principles of mechanics of materials, such as Figure 4 As shown, when the cylinder is subjected to a uniformly distributed load of its own weight, it is simplified to a simple mechanical cantilever beam model, and the following formula can be obtained through calculation: (9);

[0086] In formula (9): R A The force is the force at the left fulcrum; R B q is the force at the right fulcrum; l is the uniformly distributed load of the cylinder's self-weight; a is the total length of the cylinder; and a is the distance from the fulcrum to both ends.

[0087] The bending moment at any point can also be calculated using the following formula: (10);

[0088] In formula (10): M is the bending moment;

[0089] And axial stress for: (11);

[0090] In formula (11): W is the section modulus for bending resistance;

[0091] Based on the above calculation formula, the maximum positive bending moment occurs at the mid-span of the cylinder, and the bending moment is... The maximum negative bending moment occurs at both the left and right suspension points, with a value of [value missing]. According to the optimization requirement of minimizing maximum bending moment, the maximum positive bending moment should be equal to the maximum negative bending moment, that is... The optimal hoisting position under the strength requirement can be determined as the distance from the end. The position where the maximum bending moment in the cylinder is located. The optimal strength hoisting design position is when the longitudinal bending moment and bending normal stress are minimized.

[0092] The maximum positive deflection occurs at the mid-span of the cylinder, and the maximum negative deflection occurs at both ends of the cylinder. The deflections are respectively and . To ensure the optimization requirement of minimizing the maximum deflection, the values at the locations where the maximum deflections occur should be equal, that is . The optimal position under the deflection requirement is determined to be . At this time, the deflection is the smallest, which is the optimal stiffness hoisting design position. Therefore, to ensure the best strength and deflection of the cylinder, in actual hoisting, the optimal hoisting position is selected to be between and from the head. In the project, the position from the head is selected as the hoisting position.

[0093] In step S5, as shown in Figure 5 , during the sling hoisting of the cylinder, due to reasons such as wind load, the cylinder may tilt and generate a certain inclination angle. Therefore, it is necessary to ensure that the lifted object can be stably and horizontally lifted without sliding or overturning at the selected inclination angle. At this time, without considering the influence of the wrap angle on the friction force, the forces of the ropes on the cylinder are simplified to the bottom contact point (i.e., the case where the wrap angle is zero). The friction force obtained by such a simplified treatment is the smallest, and the calculated value is relatively the safest. For two symmetric steel ropes, the relationship between the magnitudes of the tensions of the two steel ropes and the position of the center of gravity of the tilted cylinder is as follows:

[0094] (12);

[0095] In formula (12): l1 is the distance from the center of gravity of the tilted cylinder to the left hoisting point; l2 is the distance from the center of gravity of the tilted cylinder to the right hoisting point; R is the radius of the cylinder, is the distance from the fulcrum to both ends, is the inclination angle of the cylinder. When the cylinder is in a balanced state during hoisting, the equilibrium equation is:

[0096] (13);

[0097] In formula (13), is the total weight of the cylinder. Combining formula (13) and arranging, we can get: (14);

[0098] When hoisting with an inclination angle, T1 > T2. At this time, the tension of the steel rope at the lower end is greater, and it is necessary to satisfy T1 < F to ensure that the hoisting load of this steel rope is within the safe range;

[0099] When the tension of the steel rope at the upper end gradually decreases until the tension drops to 0, at this time, The cylinder may overturn; therefore, the larger the cylinder radius R, the smaller the safe range of the tilt angle, and the more likely the cylinder is to overturn.

[0100] The expressions for the pressure FN and frictional force FS1 between the wire rope and the cylinder during the hoisting process are: (15);

[0101] To prevent the drum from slipping, the pressure and friction between the wire rope and the drum must satisfy the following relationship: (16);

[0102] In formula (16): f is the coefficient of friction when the wire rope slides against the drum, therefore The range of values ​​is .

[0103] Therefore, the range of the tilt angle is not only related to the cylinder radius R, but also closely related to the material properties of the cylinder and the wire rope. When the tilt angle exceeds its critical value, the cylinder and the wire rope will not be able to maintain sufficient friction to prevent slippage, leading to slippage and overturning of the lifting device. This phenomenon can cause a series of serious consequences, including uncontrolled slippage of objects, equipment damage, and even personal injury or death. Therefore, in actual lifting operations, the tilt angle range must be accurately calculated and strictly controlled to ensure that it is always kept below the safe limit to prevent potential slippage hazards and unforeseen safety accidents.

[0104] The following section details the specific implementation steps and actual effects of this application, using engineering examples as examples:

[0105] Geometric parameters for the wind turbine casing hoisting process: outer diameter , inner diameter Wall thickness Material parameters: density Young's modulus Poisson's ratio shear modulus Tensile yield strength ;

[0106] 1. Selection of wire rope:

[0107] The total weight of the object being lifted, the hook, and the rigging in this invention is 12 tons. Two steel wire ropes are used for lifting, one bent and two strands, for two-point lifting. Assuming the angle between the steel wire rope and the vertical line of the object being lifted is 60°, this invention uses 60° for calculation. Without considering the safety factor, according to formula (1), the tension of the steel wire rope is... The safety factor for the wire rope used in this hoisting operation is selected as 6. According to formula (2), the calculated tension of the wire rope is... According to calculation Referring to Appendix A.6 of GB / T20118-2017 "General Technical Conditions for Steel Wire Ropes" for 6x37M type steel wire rope, select the appropriate steel wire rope model. The recommended specifications are: steel wire rope grade 1960, minimum breaking strength 250KN, and steel wire rope diameter 20mm. The final selected steel wire rope must be intact and free from any damage. If damage is found, it must be used in accordance with GB50798-2012 "Specifications for Lifting Engineering of Large Petrochemical Equipment," considering different reduction factors based on the degree of damage.

[0108] 2. Selection and verification of hoisting angle:

[0109] This invention proposes an optimized method for cylinder hoisting, which improves the safety and efficiency of the hoisting process by scientifically selecting the hoisting wrap angle. Existing research indicates that to prevent slippage and overturning during hoisting, the wrap angle for cylinder hoisting typically needs to be greater than 180°. However, theoretical analysis shows that a larger wrap angle is not always better; an excessively large wrap angle can lead to uneven stress distribution on the cylinder and a significant increase in bending moment fluctuations. Considering both hoisting efficiency and operational difficulty, the wrap angle selection in engineering practice is generally limited to between 180° and 270°.

[0110] Through calculation and simulation analysis, this invention has conducted an in-depth study on the bending moment distribution of the cylinder under different wrap angles. Based on the calculation in step 3, it can be concluded that the in-plane bending moment of the cylinder varies with different angles. The changing trend, such as Figure 6 As shown, the variation trend of in-plane bending moment with different angles (including 90°, 100°, 112.5°, 120°, and 135°) of the thin-walled cylinder was calculated. The study found that when the half-angle is too large, the stress distribution on the cylinder is uneven, and the bending moment fluctuation increases significantly. Therefore, when selecting the angle, it is necessary to consider not only the maximum bending moments in both positive and negative directions, but also to comprehensively observe the overall stress situation of the cylinder to determine the optimal angle.

[0111] Through further analysis Figure 6 From the overall trend of change, it can be found that when the half-angle of wrapping is 120°, the bending moment distribution of the cylinder is the most stable, the overall fluctuation is the smallest, and the stress distribution is uniform. To verify the above theoretical results, refer to Figures 7 to 9 The present invention further selected three cases with half-cover angles of 90°, 120° and 135° for simulation and comparison.

[0112] Although calculations show that the ellipticity at 135° is 1.02%, the smallest of the three, from... Figure 6It can be seen that the overall condition of the cylinder is not as good as that of 240° under this condition. To further verify the accuracy of the theory, based on step 4, theoretical analysis and simulation verification were conducted on the influence of different semi-enclosed angle structures on the ellipticity of the cylinder. It was found that using a specific semi-enclosed angle structure can effectively reduce the deformation of the cylinder during the support process. The specific data are as follows:

[0113] Table 1. Roundness and relative ellipticity of cross sections at different wrap angles

[0114]

[0115] Since the theoretical derivation of this invention is based on a two-dimensional plane, there is a certain error between the theoretical and simulated values. As can be seen from the above data, when the half-cover angle is 120°, the theoretical relative ellipticity of the cylinder reaches its lowest value of 0.91%, indicating that the shimming and hoisting at this angle has the best effect on maintaining the shape of the cylinder. The 120° half-cover angle shimming and hoisting can more effectively control the deformation of the cylinder and improve the overall structural stability. Furthermore, although the simulation results may show larger errors at both ends due to boundary effects, these errors are within a controllable range. Moreover, the simulation results are basically consistent with the theoretical calculation trends, verifying the rationality and reliability of the structural design of this invention. Therefore, this invention preferably uses a 120° half-cover angle (cover angle 240°) for shimming to improve the safety and stability of equipment operation.

[0116] 3. Maximum lifting tilt angle

[0117] The maximum hoisting angle can be obtained according to formula (16). The coefficient of friction between the wire rope and the cylinder depends on the materials of the cylinder and the wire rope. Based on the given material parameters in the example, when using a wire rope to lift a cylinder made of Q345R material, the coefficient of friction between the wire rope and the cylinder is... The value is typically between 0.10 and 0.30. The specific value depends on the contact surface conditions, material surface properties, etc. In "sling hoisting" projects, the center of gravity shifts when tilted, causing uneven forces on the ropes or hoisting equipment. At a certain angle, the cylinder may slip or overturn, potentially causing objects to fall or even flip. Therefore, clamps, straps, and other securing devices can be used to help stabilize the cylinder and reduce movement and swaying during hoisting.

[0118] This invention, focusing on the dynamic simulation and optimization of the hoisting process for wind turbine casings, has significant practical implications and application value. By constructing a precise model and combining it with advanced simulation technology, various situations during the hoisting process can be simulated, providing a scientific basis for optimizing the hoisting scheme. Optimizing the hoisting scheme allows for the rational arrangement of hoisting positions, hoisting wrap angles, and hoisting inclination angles, effectively reducing risks such as slippage and overturning during hoisting. This invention not only helps solve current hoisting challenges in the marine engineering field but also provides valuable reference and guidance for future marine engineering technology development. Continuous optimization of hoisting schemes and techniques can drive continuous innovation and progress in marine engineering technology.

[0119] This invention identifies high-risk areas during hoisting by calculating the distribution of axial force, shear force, and bending moment under theoretical and actual wrap angles, effectively preventing localized damage or slippage accidents caused by stress concentration. It introduces calculation and evaluation methods for absolute and relative ellipticity to ensure the shape stability of the cylinder during hoisting, avoiding subsequent installation or usage problems caused by excessive deformation. Through simplified longitudinal and inclined hoisting models, the optimal hoisting position and maximum safe tilt angle are calculated, ensuring both strength and stiffness requirements while considering practical feasibility, significantly improving hoisting safety and efficiency. Through tribological analysis and tilt angle limitation calculations, it effectively suppresses swaying and sliding phenomena caused by wind loads, reducing the risk of cylinder overturning, making it particularly suitable for hoisting operations in complex environments such as marine engineering.

[0120] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. An optimized process for hoisting and hauling large offshore wind turbine casing structures, characterized in that: include, S1. Establish a mechanical model that considers material properties and wire rope properties for the hoisting process of wind turbine casing; S2. Calculate the theoretical wrap angle to obtain the axial force, shear force and bending moment distribution in the plane of the cylinder during the wrap lifting process. Based on the actual wrap angle, predict the risk location during the lifting process. S3. Calculate the radial displacement of the cylinder at various angles, and calculate the absolute ellipticity and relative ellipticity of the wind turbine cylinder based on the obtained radial displacement. S4. Based on the simplified longitudinal mechanical model of wind turbine cylinder hoisting, calculate the theoretical hoisting position and form a calculation algorithm to accurately predict the reasonable hoisting position; S5. Based on the simplified mechanical model of the inclined hoisting of the wind turbine cylinder, calculate the theoretical hoisting angle and determine the maximum hoisting angle under the hoisting method; In step S5, for the two symmetrical wire ropes, the relationship between the tension of the two wire ropes and the position of the center of gravity of the inclined drum is as follows: (12); In formula (12): l is the total length of the cylinder; l1 is the position of the cylinder's center of gravity from the left lifting point after tilting; l2 is the position of the cylinder's center of gravity from the right lifting point after tilting; R is the cylinder radius. The distance from the fulcrum to both ends, Let be the tilt angle of the cylinder. When the cylinder is in equilibrium during hoisting, the equilibrium equation is: （13） ； In formula (13), Given the total weight of the cylinder, we can obtain the following by combining formula (13): (14); When hoisting with an inclination angle, T1 > T2. At this time, the pulling force of the wire rope at the lower end is greater, and it is necessary to satisfy T1 < F to ensure that the hoisting load of the wire rope is within the safe range. When the pulling force on the wire rope at the upper end gradually decreases until the pulling force drops to 0, at this time, the cylinder body overturns. Therefore, when the radius R of the cylinder body is larger, the safe range of the inclination angle is smaller, and it is easier for the cylinder body to overturn; The pressure F between the wire rope and the cylinder during hoisting. N With frictional force F S1 The expression is: (15); To prevent the drum from slipping, the pressure and friction between the wire rope and the drum must satisfy the following relationship: (16); In formula (16): f is the coefficient of friction when the wire rope slides against the drum, therefore The range of values ​​is .

2. The optimized process for hoisting and hauling a large offshore wind turbine casing structure according to claim 1, characterized in that: In step S1, Q345R steel is selected as the cylinder material. Without considering a safety factor, the tension of the wire rope is: (1); In formula (1): T is the tension in each wire rope; The maximum lifting weight of the lifting equipment is n; n is the number of wire ropes used, using two strands in one bend, with two lifting points, which is equivalent to 4 wire ropes. The angle between the wire rope and the horizontal plane of the hoisted load; In the selection of wire rope, the tensile force P of the wire rope is calculated using the following formula: (2); In formula (2): k is the safety factor for the use of wire rope, and the sling is made of 6x37 type wire rope in the form of a ring or 8 strands.

3. The optimized process method for hoisting and installing a large offshore wind turbine casing structure according to claim 2, characterized in that: In step S2, the cylindrical structure is twice statically indeterminate, and the axial force of the curved beam... Shear force and bending moment Based on the boundary conditions: （3）； In formula (3), , , These are the axial force, shear force, and bending moment of the curved beam, respectively. , , These are the axial force, shear force, and bending moment caused by gravity within the cylindrical surface, respectively. , , The axial force, shear force, and bending moment are caused by the uniformly distributed force generated by the wire rope pulling the cylinder. , , The axial force, shear force, and bending moment caused by the tension in the wire rope; , , The axial force, shear force, and bending moment are caused by symmetrical pressure within the cylindrical surface. , , The axial force, shear force, and bending moment are caused by the symmetrical bending moment within the cylindrical surface. The solution is obtained using the unit force method from mechanics of materials. A horizontal axial unit force is applied at point A at the end of the curved beam. Unit bending moment in the axial direction Establish the force method equations for a second-order statically indeterminate curved beam. (4); In formula (4), unit force When acting alone, point A along Displacement caused by direction; unit force and unit bending moment When both are acting simultaneously, point A along... Displacement caused by direction; unit bending moment When acting alone, point A along Displacement caused by direction; , , In unit force When the uniformly distributed force of the sling, the weight of the cylinder, and the tension of the wire rope act individually, point A along... Displacement caused by direction; , , To be respectively at unit bending moment When the uniformly distributed force of the sling, the weight of the cylinder, and the tension of the wire rope act individually, point A along... Displacement caused by direction; Calculate formula (4) and substitute the result into formula (3) to solve for the distribution of axial force, shear force and bending moment in the plane of the cylinder during the hoisting process. In the actual hoisting project, substitute the actual parameters to obtain the distribution of axial force, shear force and bending moment in the plane of the cylinder during the hoisting process. Thus, the risk position in the hoisting process can be predicted by the actual wrap angle.

4. The optimized process method for hoisting and installing a large offshore wind turbine casing structure according to claim 3, characterized in that: In step S3, the formulas for calculating the radial displacement of the cylinder at various angles are as follows. when When the radial displacement equation is: (5); when When the radial displacement equation is: (6); In formulas (5) and (6): , , and , , These are the angles under a unit radial force. The axial force, shear force, and bending moment on the left and right sides, with the expression for the internal forces of the curved beam under a unit radial force is as follows: (7); In formula (7): , , These represent the axial force, shear force, and bending moment of the curved beam under unit radial force. Based on the obtained radial displacement, the formulas for calculating the absolute and relative ellipticity of the wind turbine casing during the hoisting process are as follows: (8); In formula (8): Absolute ellipticity; Relative ellipticity; and These are the maximum and minimum deformation diameters of the wind turbine casing, respectively. It is the inner diameter of the cross section.

5. The optimized process method for hoisting and installing a large offshore wind turbine casing structure according to claim 4, characterized in that: In step S4, based on the principles of mechanics of materials, when the cylinder as a whole is subjected to a uniformly distributed load of its own weight, it is simplified into a simple mechanical cantilever beam model, and the following formula can be obtained through calculation: （9）； In formula (9): R A The force is the force at the left fulcrum; R B q is the force at the right fulcrum; l is the uniformly distributed load of the cylinder's self-weight; a is the total length of the cylinder; and a is the distance from the fulcrum to both ends. The bending moment at any point can also be calculated using the following formula: (10); In formula (10): M is the bending moment; And axial stress for: (11); In formula (11): W is the section modulus for bending resistance; Based on the above calculation formula, the maximum positive bending moment occurs at the mid-span of the cylinder, and the bending moment is... The maximum negative bending moment occurs at both the left and right suspension points, with a value of [value missing]. According to the optimization requirement of minimizing maximum bending moment, the maximum positive bending moment should be equal to the maximum negative bending moment, that is... The optimal hoisting position under the strength requirement can be determined as the distance from the end. The position where the maximum bending moment in the cylinder is located. The optimal strength hoisting design position is when the longitudinal bending moment and bending normal stress are minimized. The maximum positive deflection occurs at the mid-span of the cylinder, and the maximum negative deflection occurs at both ends of the cylinder, with deflections of respectively... and To ensure the optimization requirement of minimizing maximum deflection, the values ​​at the points where maximum deflection occurs must be equal, i.e. The optimal position under the deflection requirement was determined as follows: At this point, the deflection is minimal, representing the optimal stiffness for the hoisting design. Therefore, to ensure optimal strength and deflection of the cylinder, the optimal hoisting position in actual hoisting is chosen from a distance of [distance from the end cap]. and In the meantime, the project selects the head. This is the hoisting location.

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