Tree type hierarchical balance hoisting calculation simulation method

Abstract

The application discloses a tree type hierarchical balance hoisting calculation simulation method, and realizes self-balance of a portal crane in folding through a hoisting rope unit and a rigid rod, the hoisting rope forces of each hoisting rope in a single lifting mechanism are basically consistent, the actual hoisting rope force state of the hoisting folding working condition is well simulated, the hoisting rope force of a single hoisting point is provided, and the accuracy of the total hoisting rope force of the single lifting mechanism is ensured, so that more accurate basis is provided for judging whether the bearing capacity of each lifting mechanism and the block hoisting point meets the demand, and finally the correctness of the structural strength checking of the block structure in the hoisting working condition is ensured.

Description

Technical Field

[0001] This invention relates to the field of calculating lifting forces on gantry cranes in marine engineering, and particularly to a tree-type hierarchical balance lifting calculation and simulation method. Background Technology

[0002] In the construction of semi-submersible production platforms, a gantry crane is often used for hoisting and assembling. The structural feature of a gantry crane is that it uses several pulley systems to arrange the lifting ropes, with each pulley system corresponding to multiple lifting points. During hoisting, the lifting rope force borne by each lifting point in each pulley system is equal. However, in traditional hoisting calculations, each lifting rope is simulated independently, resulting in inconsistent lifting rope forces at each lifting point, which is significantly inconsistent with the actual conditions of gantry crane hoisting. Summary of the Invention

[0003] This invention provides a tree-type hierarchical balancing hoisting calculation simulation method, which can automatically balance the hoisting rope force under the hoisting and closing condition of the gantry crane, so as to simulate that the hoisting rope force borne by each hoisting point in each pulley group is equal during the actual hoisting process, thereby making the hoisting verification calculation of the block more accurate.

[0004] This invention provides a tree-based hierarchical balanced hoisting calculation and simulation method, comprising the following steps:

[0005] S1. Determine the number of lifting points on the gantry crane. Each lifting point is equipped with one primary lifting rope unit.

[0006] S2. The upper ends of every two primary suspension rope units are connected to the two ends of a primary rigid rod. Secondary suspension rope units are set on the primary rigid rods, with the lower end of the secondary suspension rope unit connected between the two ends of the primary rigid rod and the upper end connected to one end of the secondary rigid rod. The upper end of any unpaired suspension rope unit is connected to a lower level rigid rod where no suspension rope unit is connected. This process is repeated, adding rigid rods and suspension rope units level by level until a single suspension rope unit can sum the suspension rope forces at all lifting points. S3. After completing the suspension rope model, import the suspension rope model into the modular structure model. Connect each lower end of the primary suspension rope to the corresponding block lifting point. Then apply the dry weight of the equipment and the self-weight of the structure to complete the calculation of the suspension rope force and the structural strength verification.

[0007] Furthermore, in step S2, when the number of lifting points m = 2 n When n is a positive integer, the upper ends of two adjacent first-level suspension rope units are connected to the two ends of the first-level rigid rod. The lower end of the second-level suspension rope unit is located at the midpoint of the first-level rigid rod, and the upper end is connected to the two ends of the second-level rigid rod. This process is repeated, adding new rigid rods and suspension rope units until a single suspension rope unit can complete the sum of the suspension rope forces at all suspension points.

[0008] Furthermore, in step S2, when the number of lifting points m≠2 nWhen n is a positive integer, the upper ends of two adjacent suspension rope units in each level are connected to the two ends of the corresponding rigid rod. This continues until an odd number of suspension rope units appear in a certain level. In this level, the upper ends of the adjacent suspension rope units are connected to the ends of the suspension rope units of the corresponding rigid rod in pairs. The remaining suspension rope unit is then connected across levels to the ends of the rigid rods below that are not connected to the suspension rope. This process is repeated, adding rigid rods and suspension rope units level by level, until a single suspension rope unit can complete the sum of the suspension rope forces at all suspension points.

[0009] 4. The tree-type hierarchical balance hoisting calculation and simulation method according to claim 3, characterized in that: in step S2, the rigid rods of level x (x≥2) satisfy the following condition: the distance from the position of the (x+1) level hoisting rope unit connected to the rigid rod of level x to both ends of the rigid rod of level x is inversely proportional to the number of first-level hoisting rope units directly or indirectly connected to both ends of the rigid rod of level x.

[0010] The technical advantages of this invention are as follows: By using a rope unit and a rigid rod, this invention achieves a consistent rope force across all ropes in a single lifting mechanism during hoisting, resulting from the self-balancing of rope forces. This effectively simulates the actual rope force state during hoisting, providing accurate rope force for individual lifting point verification and ensuring the accuracy of the total rope force of a single lifting mechanism. Consequently, it provides a more accurate basis for determining whether the load-bearing capacity of each lifting mechanism and block lifting point meets the requirements, ultimately ensuring the correctness of the structural strength (UC, unity check, ratio of calculated stress to allowable stress) verification under the block structure hoisting conditions. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the gantry crane lifting rope in an embodiment of the present invention;

[0012] Figure 2 This is a schematic diagram of the simulation calculation of the suspension rope in the existing technology;

[0013] Figure 3 This is a diagram showing the results of simulating and calculating the force on the suspension rope in existing technologies;

[0014] Figure 4 This is a diagram showing the UC result of the suspension rope simulation calculation structure in the existing technology;

[0015] Figure 5 This is a schematic diagram of the suspension rope simulation calculation in Embodiment 1 of the present invention;

[0016] Figure 6 This is a diagram showing the results of the simulated calculation of the suspension rope force in Embodiment 1 of the present invention;

[0017] Figure 7 This is a diagram showing the result of the simulated calculation of the suspension rope structure UC in Embodiment 1 of the present invention;

[0018] Figure 8 This is a schematic diagram of the suspension rope simulation calculation in Embodiment 2 of the present invention;

[0019] Figure 9 This is a diagram showing the results of the simulated calculation of the suspension rope force in Embodiment 2 of the present invention; Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0021] Appendix Figures 1 to 9 As shown, this embodiment of the invention provides a tree-type hierarchical balanced hoisting calculation simulation method, applicable to gantry crane hoisting conditions. By using hoisting rope units and rigid bars, and utilizing the principle of balance bars, it effectively replaces the pulley blocks and wire ropes in actual working conditions. This achieves the goal of simulating that the hoisting rope force borne by each hoisting point in each pulley block is equal during the actual hoisting process, thereby making the hoisting verification calculation of the blocks more accurate. At the same time, it can also more accurately determine whether the force on each pulley block is within the limit of the equipment's capacity.

[0022] In the lifting operation of a gantry crane, the gantry crane has several lifting mechanisms. Each lifting mechanism includes a pulley block, a balance beam, and lifting points on the block, all connected by a steel wire rope. Therefore, under static conditions, the lifting points in each lifting mechanism can withstand the same rope force.

[0023] This invention discloses a tree-type hierarchical balanced hoisting calculation and simulation method, comprising the following steps:

[0024] S1. Determine the number of lifting points on the gantry crane. Each lifting point is equipped with one primary lifting rope unit.

[0025] S2. The upper ends of every two primary suspension rope units are connected to the two ends of a primary rigid rod. Secondary suspension rope units are set on the primary rigid rod, with the lower end of the secondary suspension rope unit connected between the two ends of the primary rigid rod and the upper end connected to one end of the secondary rigid rod. The upper end of any unpaired suspension rope unit is connected to a lower rigid rod where no suspension rope unit is connected. This process is repeated, adding rigid rods and suspension rope units at each level until a single suspension rope unit can complete the sum of the suspension rope forces at all suspension points.

[0026] Step S2 includes two cases:

[0027] (1) When the number of suspension points m = 2 nWhen n is a positive integer, the upper ends of two adjacent first-level suspension rope units are connected to the two ends of the first-level rigid rod. The lower end of the second-level suspension rope unit is located at the midpoint of the first-level rigid rod, and the upper end is connected to the two ends of the second-level rigid rod. This process is repeated, adding new rigid rods and suspension rope units until a single suspension rope unit can complete the sum of the suspension rope forces at all suspension points.

[0028] (2) When the number of suspension points m≠2 n When n is a positive integer, the upper ends of two adjacent suspension rope units in each level are connected to the two ends of the corresponding rigid rod. This continues until an odd number of suspension rope units appear in a certain level. In this level, the upper ends of the adjacent suspension rope units are connected to the ends of the suspension rope units of the corresponding rigid rod in pairs. The remaining suspension rope unit is then connected across levels to the ends of the rigid rods below that are not connected to the suspension rope. This process is repeated, adding rigid rods and suspension rope units level by level, until a single suspension rope unit can complete the sum of the suspension rope forces at all suspension points.

[0029] The rigid rod of grade x (x≥2) satisfies the following condition: the distance from the position of the (x+1) grade suspension rope unit connected to the rigid rod of grade x to both ends of the rigid rod of grade x is inversely proportional to the number of first-level suspension rope units directly or indirectly connected to both ends of the rigid rod of grade x.

[0030] S3. After completing the suspension rope model, import the suspension rope model into the modular structure model. Connect each lower end of the primary suspension rope to the corresponding block lifting point. Then apply the dry weight of the equipment and the self-weight of the structure to complete the suspension rope force and structural strength verification.

[0031] Example 1, Figure 1 The diagram below shows the lifting rope of the gantry crane in Embodiment 1 of the present invention. Taking a gantry crane with 12 lifting mechanisms as an example, the maximum lifting capacity of a single lifting mechanism is 1680 tons. Each lifting mechanism is connected to 16 lifting points on the block by a set of wire ropes through a pulley block and a balance beam mechanism. Finally, during the lifting process, it is required that the lifting rope force borne by the corresponding 16 lifting points in each lifting mechanism is equal.

[0032] In the existing technology, the nodes on the suspension rope are fixedly constrained (111111, where 1 represents the constrained node's degree of freedom, in order: X, Y, Z translational degrees of freedom and X, Y, Z rotational degrees of freedom). The two ends of the suspension rope element release five degrees of freedom except for the axial displacement degree of freedom (the suspension rope element is only subjected to axial force, 011111-011111, where 1 represents releasing the degree of freedom at the element's endpoint, and 0 represents not releasing the degree of freedom at the element's endpoint, in order: X, Y, Z translational degrees of freedom and X, Y, Z rotational degrees of freedom). The suspension rope model is as follows: Figure 2 As shown, Figure 3 For the calculation results of the suspension rope force, from Figure 3The results show that existing simulations of the lifting rope calculations cannot ensure that the lifting rope forces at each lifting point in the various lifting mechanisms are equal, nor can they guarantee that the total lifting rope force of a single lifting mechanism exceeds the lifting rope capacity (1680 tons). Most seriously, incorrect lifting rope forces lead to inaccurate structural strength UC (UnityCheck, the ratio of internal stress to allowable stress in structural elements). Figure 4 This means that the safety of the module hoisting cannot be guaranteed.

[0033] In this embodiment, the number of lifting points m = 16, such as Figure 5 As shown, a total of 5 levels of suspension rope units and 4 levels of rigid rods are set up, including 16 first-level suspension rope units, 8 second-level suspension rope units, 4 third-level suspension rope units, 2 fourth-level suspension rope units, and 1 fifth-level suspension rope unit. The rigid rods from the fourth level to the first level are 8, 4, 2, and 1 respectively. The two ends of the first-level suspension rope unit are connected to the lifting point and the two ends of the first-level rigid rod, respectively. The two ends of the second-level suspension rope unit are connected to the midpoint of the first-level rigid rod and the two ends of the second-level rigid rod, respectively, and so on.

[0034] The suspension rope unit also releases five degrees of freedom except for the axial displacement degree of freedom of the suspension rope (the suspension rope unit is only subject to axial force, 011111-011111, where 1 represents releasing the degree of freedom at the end of the unit, and 0 represents not releasing the degree of freedom at the end of the unit, in order: X, Y, Z translational degrees of freedom and X, Y, Z rotational degrees of freedom). The nodes at both ends of the rigid rod constrain the X / Y translational degrees of freedom on the horizontal plane, but do not constrain the vertical translational degrees of freedom and the three rotational degrees of freedom (110000, where 1 represents constraining the degree of freedom at the node, and 0 represents not constraining the degree of freedom at the node, in order: X, Y, Z translational degrees of freedom and X, Y, Z rotational degrees of freedom). In this way, the midpoint of the rigid rod connected by the upper suspension rope is used as the fulcrum of the lever, and the rigid rod acts as a lever. The suspension rope forces at both ends of the rigid rod reach equilibrium, and finally the suspension rope forces of the 16 suspension ropes in a single lifting mechanism tend to be consistent. After completing the hoisting rope model, import it into the modular structure model. Connect each lower end of the primary hoisting rope to the corresponding module lifting point. Then, apply the dry weight of the equipment and the self-weight of the structure to perform hoisting calculations, and obtain the hoisting rope force and structural strength UC calculation results as follows: Figure 6 , Figure 7 As shown.

[0035] The calculation results of the existing hoisting calculation method are compared with the calculation results of the embodiments of this application, as shown in Table 1:

[0036] Table 1

[0037]

[0038] Example 2: The number of lifting points in each group (m ≠ 2) nWhen n is an integer, to ensure that each lifting point bears equal rope force, according to the principle that the torque at both ends of the rigid rod is equal, the rigid rod of level x (x≥2) satisfies the following condition: the distance from the position of the (x+1) level rope unit connected to the rigid rod of level x to both ends of the rigid rod of level x is inversely proportional to the number of first-level rope units directly or indirectly connected to both ends of the rigid rod of level x. The so-called indirectly connected first-level rope units refer to the total number of first-level rope units supported by the upper-level rigid rod and rope units.

[0039] Taking 15 lifting points per group as an example, the two lengths of the rigid rod are arranged as follows: Figure 8 As shown, there are 7 first-level rigid rods, 4 second-level rigid rods, 2 third-level rigid rods, and 1 fourth-level rigid rod. The left end of the rightmost second-level rigid rod is connected to 2 first-level suspension rope units, and the right end is connected to 1 first-level suspension rope unit. The ratio of the distance from the position of the third-level suspension rope unit on the rightmost second-level rigid rod to both ends is 1:2, and so on. The ratio of the distance from the position of the fourth-level suspension rope unit on the rightmost third-level rigid rod to both ends is 3:4, and the ratio of the distance from the position of the fifth-level suspension rope unit on the rightmost fourth-level rigid rod to both ends is 7:8.

[0040] When the number of lifting points is 9, the first-level lifting rope units are paired up in pairs, with their upper ends connected to both ends of the first-level rigid rod. At this time, there is still 1 first-level rigid rod left, with its upper end connected to the end of the fourth-level rigid rod that is not connected to the lifting rope unit. This allows the 9 first-level lifting rope units to be gathered into 1 fifth-level lifting rope unit.

[0041] The calculation results of the suspension rope force are as follows: Figure 9 As shown.

[0042] from Figure 9 As can be seen, the force of each lifting rope calculated by the tree-type hierarchical balance hoisting calculation simulation method is basically consistent, which meets the actual use requirements.

[0043] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A tree-type hierarchical balanced hoisting calculation and simulation method, comprising the following steps, characterized in that, S1. Determine the number of lifting points on the gantry crane. Each lifting point is equipped with one primary lifting rope unit. S2. The upper ends of every two primary suspension rope units are connected to the two ends of a primary rigid rod. Secondary suspension rope units are set on the primary rigid rod, with the lower end of the secondary suspension rope unit connected between the two ends of the primary rigid rod and the upper end connected to one end of the secondary rigid rod. The upper end of any unpaired suspension rope unit is connected to a lower rigid rod where no suspension rope unit is connected. This process is repeated, adding rigid rods and suspension rope units at each level until a single suspension rope unit can complete the sum of the suspension rope forces at all suspension points. S3. After completing the suspension rope model, import the suspension rope model into the modular structure model. Connect each lower end of the primary suspension rope to the corresponding block lifting point. Then apply the dry weight of the equipment and the self-weight of the structure to complete the calculation of the suspension rope force and the structural strength verification. In step S2, when the number of lifting points m = 2 n When n is a positive integer, the upper ends of two adjacent first-level suspension rope units are connected to the two ends of the first-level rigid rod. The lower end of the second-level suspension rope unit is located at the midpoint of the first-level rigid rod, and the upper end is connected to the two ends of the second-level rigid rod. This process is repeated, adding new rigid rods and suspension rope units until a single suspension rope unit can complete the sum of the suspension rope forces at all suspension points. In step S2, when the number of lifting points m≠2 n When n is a positive integer, the upper ends of two adjacent suspension rope units in each level are connected to the two ends of the corresponding rigid rod. This continues until an odd number of suspension rope units appear in a certain level. In this level, the upper ends of the adjacent suspension rope units are connected to the ends of the suspension rope units of the corresponding rigid rod in pairs. The remaining suspension rope unit is then connected across levels to the ends of the rigid rod below that are not connected to the suspension rope. This process is repeated, adding rigid rods and suspension rope units level by level until a single suspension rope unit can complete the sum of the suspension rope forces at all suspension points. In step S2, the rigid rod of level x (x≥2) satisfies the following condition: the distance from the position of the (x+1) level rope unit connected to the rigid rod of level x to both ends of the rigid rod of level x is inversely proportional to the number of first-level rope units directly or indirectly connected to both ends of the rigid rod of level x, so that each suspension point bears an equal rope force.

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