A Numerical Simulation Method for Penetration Analysis of Integrated Installation of Drag Anchor and Anchor Chain

Abstract

The present application relates to a numerical simulation method for the integrated installation and penetration analysis of a drag anchor - anchor chain, belonging to the technical field of numerical simulation of drag anchor - anchor chain. The method uses the CEL finite element calculation method in the ABAQUS numerical analysis software. The method comprises the following steps: S1. Establish a numerical calculation and analysis model; S2. Assign corresponding material properties to each established model; S3. Assemble the numerical calculation and analysis model; S4. Establish a dynamic display analysis step; S5. Establish the interaction among the drag anchor foundation model, the anchor chain model, and the soil body model; S6. Define boundary conditions; S7. Set the material assignment of the cavity element as "empty", assign the soil body the material properties set in step S2, and apply a geostress field to the soil body; S8. Perform mesh division on the established numerical calculation and analysis model and submit it for calculation; S9. Post - processing; It has the effect of truly describing the interaction among the drag anchor - anchor chain - soil body in a sandy soil environment and improving the accuracy and reliability of the numerical simulation results.

Description

Technical Field

[0001] The present invention relates to the technical field of numerical simulation of drag anchors - anchor chains, and particularly relates to a numerical simulation method for integrated installation and penetration analysis of drag anchors - anchor chains. Background Art

[0002] Currently, the most commonly used finite element calculation methods are mainly the Lagrangian method and the Eulerian method. The former is a calculation method in which the mesh adheres to the material, and the mesh deforms with the material, being able to well track the changes in the material boundary. However, for large - deformation problems, the mesh will undergo severe deformation, resulting in non - convergence of the calculation. The latter adopts a method where the mesh is fixed and the material can flow freely in the mesh, and the mesh does not deform with the material, overcoming the numerical singularity brought about by mesh distortion in the Lagrangian method. However, the Eulerian method cannot well track the changes in the material boundary. CEL (Coupled Eulerian Lagrangian) absorbs the advantages of both Eulerian and Lagrangian meshes. The soil body adopts the method where the mesh is fixed and the material can flow freely in the mesh, completely avoiding the distortion of elements during large - deformation calculations. The structure adopts the Lagrangian algorithm to track the changes in the contact surface between the soil and the structure through the boundary of the structure.

[0003] Since the CEL technology was proposed, it has developed rapidly. This technology has been widely applied in large - deformation problems. The penetration process of drag anchors - anchor chains in sandy soil sites belongs to a typical large - deformation problem of soil bodies. Some scholars have carried out research on the penetration of drag anchors using the CEL technology, initially verifying the feasibility of this technology for the installation analysis of drag anchors.

[0004] The research topics carried out by scholars include: research on the penetration of drag anchors in clay sites, research on the influence of the side - inclination angle of the anchor shank on the diving performance of drag anchors in sandy soil, and research on the penetration of drag anchors - anchor chains in clay.

[0005] In the research on the penetration of drag anchors in clay sites, the drag anchor is a rigid body, the soil body is clay with undrained shear strength increasing linearly with depth, and the Eulerian mesh is adopted. The coupling action between the cable and the soil, and the cable and the anchor is replaced by applying a varying drag force and direction at the mooring point. To a certain extent, they have proved the feasibility of using the CEL method to analyze the penetration process of drag anchors in clay sites. However, in this research, the drag - anchor model is overly simplified, and there is a large contingency in the calculated value of the drag - force formula at the mooring point; there are many empirical coefficients in the adopted drag - force calculation formula, and the values are not clear (for example: the value range of the cable - end resistance coefficient is 7.6 - 14); the most prominent defect is the failure to simulate the anchor chain, resulting in unreliable calculation results.

[0006] In the study of the influence of the shank inclination angle on the diving performance of the towing anchor in sand, the towing anchor is a simplified model of MK5, and the soil friction angle is 20°, 25° and 30°. The towing anchor motion analysis model without anchor chain traction is adopted, that is, the movement of the towing anchor relies on the horizontal traction speed applied to the mooring point at the front end of the anchor shank to replace the coupling effect between the cable and the soil, and the cable and the anchor. This study proves the feasibility of using the CEL method to analyze the penetration process of the towing anchor in sand sites to a certain extent, but it also has similar problems to the research on the penetration of the towing anchor in clay sites. First, the towing anchor model is over-simplified; secondly, in practice, the anchor chain towing speed is equal to the horizontal and vertical combined speeds of the mooring point of the towing anchor, and during the penetration process of the towing anchor, the horizontal speed changes all the time and is also affected by soil parameters, anchor parameters, etc. Similarly, the horizontal and vertical speeds have a significant impact on the penetration process of the towing anchor, so the constant horizontal traction speed applied to the mooring point is inconsistent with the actual situation. That is, the research method is quite different from the actual penetration process of the towing anchor, and the calculation results are unreliable.

[0007] In the study of the penetration of towed anchor-chain in clay, the researchers simulated the anchor chain in the CEL model. By simplifying the anchor chain links into cylindrical rigid bodies, using the Link connector provided by Abaqus to simulate the contact between the anchor chains, and simplifying the tow anchor into a rectangular plate or wedge, the simplified towed anchor-chain penetration process in clay was successfully simulated. However, when this method was used to simulate the penetration of towed anchor-chain in sandy soil sites, the calculation did not converge and the Euler soil body "irregular motion" was problematic. After analysis, it was found that the soil beds in the above studies were all clay, and the anchor chain tensions were 70t and 40t respectively. Under these conditions, the CEL method can be calculated smoothly. However, when the towing anchor-chain penetrates into the sand, the tension on the anchor chain will reach the order of thousands of tons, resulting in excessive deformation of the Link connector in the U3 direction, causing the calculation to not converge, and also inconsistent with the actual chain link connection behavior. This is related to the fact that the Link connector only constrains the relative displacement between the nodes in U1 (one direction). Although the Link connector releases the rotational freedom between the nodes, it fails to accurately constrain the relative displacement between the nodes, causing the Link connector to deform during the calculation process, sharing part of the displacement of the towing anchor and the anchor chain, and causing the potential energy to be greater than the total energy during the numerical calculation process, resulting in the calculation termination.

[0008] In summary, existing studies have failed to truly describe the interaction between the towing anchor-anchor chain and soil in the sandy soil environment, resulting in large errors in the output results of the numerical simulation calculation of the integrated installation penetration of the towing anchor-anchor chain, or even inability to calculate. Summary of the invention

[0009] The invention provides a numerical simulation method for penetration analysis of integrated installation of a drag anchor and anchor chain.

[0010] The technical solution adopted by the present invention to solve its technical problems is: a numerical simulation method for the integrated installation and penetration analysis of a drag anchor - anchor chain, which uses the CEL finite element calculation method in the ABAQUS numerical analysis software. The method includes the following steps:

[0011] S1. Establish a numerical calculation and analysis model, which includes a soil model, a drag anchor foundation model, a link model, and an anchor chain model;

[0012] In the soil model, the soil is set as an Euler material, and cavity elements are set on the soil surface;

[0013] The drag anchor foundation model is built using Lagrangian solid modeling and set as a rigid body;

[0014] The link model is set as a rigid body;

[0015] The anchor chain model is formed by connecting the links using a Join - Rotation combination connector;

[0016] S2. Assign corresponding material properties to each of the established models;

[0017] S3. Assemble the numerical calculation and analysis model, set the position and shape of the drag anchor foundation model, and set the position of the anchor chain model;

[0018] S4. Establish a dynamic display analysis step, which includes: a ground stress balance analysis step, a body force application analysis step for the drag anchor foundation model - anchor chain model, and a drag analysis step for the drag point of the anchor chain model;

[0019] S5. Establish the interactions between the drag anchor foundation model, the anchor chain model, and the soil model, and set general contact conditions between the drag anchor foundation model, the anchor chain model, and the soil model;

[0020] Between the drag anchor foundation model and the anchor chain model, a Join - Rotation combination connector is used to connect the mooring point of the drag anchor foundation model with the first link of the anchor chain model, and historical variable output is set for the Join - Rotation combination connector to output the tensile forces at the mooring point of the drag anchor foundation model and the drag point of the anchor chain model;

[0021] S6. Define boundary conditions, set the horizontal velocity of the nodes on the outer boundary of the soil elements and cavity elements in the Euler region and set it as an Euler absorption boundary, and set the velocity of the bottom boundary nodes for the soil elements and cavity elements in the Euler region;

[0022] S7. Set the material assignment of the cavity elements as "empty", assign the soil the material properties set in step S2, and apply a ground stress field to the soil;

[0023] S8. Mesh the established numerical calculation and analysis model and submit it for calculation;

[0024] S9. Post-process, extract the horizontal and vertical displacements and tensile forces at the mooring point of the drag anchor foundation model, extract the tensile force at the drag point, and extract the horizontal and vertical displacements at the anchor tip of the drag anchor foundation model.

[0025] The link model adopts a combination form of a cylinder-sphere end.

[0026] The height range of the cavity is greater than the heave height during the penetration process of the drag anchor-chain.

[0027] In step S2, the stress-strain relationship of sand is described by an ideal elastoplastic constitutive model that satisfies the Mohr-Coulomb yield condition.

[0028] In step S2, the stress-strain relationship of clay is described by an ideal elastoplastic Tresca constitutive model.

[0029] In step S2, the material properties include one or more of mass density, Young's modulus, Poisson's ratio, friction angle, dilation angle, yield strength, and K0 coefficient.

[0030] In step S3, set the initial position of the drag anchor foundation model at the mud surface and the initial position of the anchor chain model to be laid flat on the seabed.

[0031] There is an angle between the anchor plate plane of the drag anchor foundation model and the mud surface.

[0032] In step S6, set the horizontal velocity of the soil elements and the nodes on the outer boundary of the cavity elements in the Euler region to 0, and set the velocity of the bottom boundary nodes to 0.

[0033] In step S8, for the soil model and cavity elements, use hexahedral elements for meshing. In the penetration area of the drag anchor foundation model, use a fine mesh with a mesh size of 0.3 m, and in the area outside the penetration area of the drag anchor foundation model, use a coarser mesh with a mesh size of 0.6 m;

[0034] The drag anchor foundation model and the link model are meshed using tetrahedral elements.

[0035] Through the above technical solutions, compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. Conduct an integrated installation and penetration analysis of the drag anchor-chain model with high reducibility in sand. The simulation environment fits the actual scenario, the interaction is accurate and stable, the calculation converges, and the empirical values are replaced by the actual calculated output values, improving the accuracy and reliability of the calculated output results;

[0037] 2. The drag anchor foundation model uses solid modeling, which overcomes the problem of unreliable calculation results caused by over-simplifying the anchor claw.

[0038] 3. The anchor chain model and the mooring point of the drag anchor foundation model and the first link of the anchor chain model are all connected by a Join-Rotation combined connector. The Rotation connector provides a rotational connection between two nodes, that is, it releases the rotational freedom between the two nodes. The Join connector provides a relative position connection between two nodes, that is, it constrains the relative displacement of the two nodes in three directions. Therefore, the Join-Rotation combined connector can release the rotational freedom of the two nodes while constraining the relative displacement of the nodes, and can accurately simulate the contact behavior between the drag anchor and the anchor chain, and between the links.

[0039] 4. The link is simulated in the form of a cylinder-sphere end combination, which reduces the end resistance suffered by the link during the calculation and is conducive to the convergence of the calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be further described below in conjunction with the drawings and embodiments.

[0041] Figure 1 It is a schematic flow diagram of the present invention;

[0042] Figure 2 It is a schematic diagram of the CEL finite element model of the drag anchor-anchor chain-soil body of the present invention;

[0043] Figure 3 It is a schematic diagram of the drag anchor foundation model of the present invention;

[0044] Figure 4 It is the result of the drag anchor-anchor chain penetration process of the present invention;

[0045] Figure 5 It is a comparison of the bearing capacity results of different model sizes perpendicular to the drag direction of the present invention;

[0046] Figure 6 It is a comparison of the penetration trajectory results of different model sizes perpendicular to the drag direction of the present invention;

[0047] Figure 7 It is a comparison of the bearing capacity results of different mesh sizes in the drag area of the present invention;

[0048] Figure 8 It is a comparison of the penetration trajectory results of different mesh sizes in the drag area of the present invention;

[0049] Figure 9 It is a comparison of the bearing capacity results of different drag speeds of the present invention;

[0050] Figure 10Comparison of penetration trajectories at different towing speeds of the present invention. Detailed implementation manners

[0051] Now, the present invention will be further described in detail with reference to the accompanying drawings. In the description of the present application, it should be understood that the orientation or positional relationship indicated by terms such as "left side", "right side", "upper part", "lower part", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. "First", "second", etc. do not represent the importance of components, so they cannot be understood as limitations to the present invention. The specific dimensions adopted in this embodiment are only for illustrating the technical solution by way of example, and do not limit the protection scope of the present invention.

[0052] As Figure 1 shown, a numerical simulation method for the integrated installation and penetration analysis of a towing anchor - anchor chain of the present invention uses the CEL finite element calculation method in the ABAQUS numerical analysis software. The method includes the following steps:

[0053] S1. Establish a numerical calculation and analysis model, which includes a soil model, a towing anchor foundation model, a link model, and an anchor chain model;

[0054] As Figure 2 shown, symmetry is considered in the soil model, and 1 / 2 of the overall area is used for modeling. The entire soil uses Eulerian material, with a length of 167 m along the towing direction, 6D = 50 m perpendicular to the towing direction (D is the width of the towing anchor), a soil depth of 30 m, and cavity elements are set on the soil surface. The height range of the cavity elements is greater than the uplift height during the penetration process of the towing anchor - anchor chain;

[0055] As Figure 3 shown, the towing anchor foundation model is modeled using Lagrangian solids, and the model of the towing anchor is the 25t MK6 type. The towing anchor foundation model is set as a rigid body;

[0056] As Figure 2 shown, the link model adopts a combination form of a cylinder - spherical end, that is, a combination of a cylinder and two hemispheres at both ends. The link model is set as a rigid body;

[0057] The anchor chain model uses a Join - Rotation combined connector to connect the links to form an anchor chain model. The total length of the anchor chain is 62 m. The radius of the cylinder in the link is 0.183 m, the length is 0.343 m, the radius of the end sphere is 0.183 m, and the length of the connector is 0.15 m.

[0058] S2. Assign corresponding material properties to each established model. Use an ideal elastoplastic constitutive model that satisfies the Mohr-Coulomb yield criterion to describe the stress-strain relationship of sand. The material properties include one or more of mass density, Young's modulus, Poisson's ratio, friction angle, dilation angle, yield strength, and K0 coefficient. In this solution, the mass density of sand is 980, Young's modulus is 12,000,000, Poisson's ratio is 0.3, the internal friction angle is set to 20°, the dilation angle is set to 0.1, and the yield stress is set to 1000.

[0059] Use an ideal elastoplastic Tresca constitutive model to describe the stress-strain relationship of clay. The parameter units in this step can be converted according to the model size units, as long as the unified unit system requirements are met.

[0060] S3. Assemble the numerical calculation analysis model. Set the position and shape of the drag anchor foundation model and the position of the anchor chain model. The initial position of the drag anchor foundation model is on the mud surface. There is an angle between the anchor plate plane of the drag anchor foundation model and the mud surface, and the angle is 48°. The distance from the anchor tip to the left boundary of the soil body is 18 m. The initial position of the anchor chain model is laid flat on the seabed, and the length is 62 m.

[0061] S4. Establish a dynamic display analysis step. The analysis steps include: a geostatic stress equilibrium analysis step, set to 10; a body force application analysis step for the drag anchor foundation model - anchor chain model, set to 5 s; a dragging analysis step for the dragging point of the anchor chain model, set to 120 s.

[0062] S5. Establish the interaction between the drag anchor foundation model, the anchor chain model, and the soil model. Set the general contact conditions between the drag anchor foundation model, the anchor chain model, and the soil model. Use a penalty function contact algorithm. The tangential direction of the contact surface follows the Coulomb friction relationship, with a friction coefficient of 0.4. The normal direction of the contact surface allows separation.

[0063] Between the drag anchor foundation model and the anchor chain model, use a Join-Rotation combined connector to connect the mooring point of the drag anchor foundation model and the first link of the anchor chain model. Set rigid bodies for the drag anchor foundation model and the individual link model. The reference point of the drag anchor foundation model is set at the mooring point. Set the historical variable output for the Join-Rotation combined connector to output the tensile forces at the mooring point of the drag anchor foundation model and the dragging point of the anchor chain model. During operation, set a separate set for the connector, and at the same time, set the historical variable output for this set.

[0064] S6. Define the boundary conditions. For the soil elements and cavity elements in the Euler region, set the horizontal velocity of the nodes on the outer boundary to 0 and set it as an Euler absorption boundary. The velocity of the nodes on the bottom boundary is set to 0.

[0065] Set symmetric boundaries for the drag anchor foundation model and the anchor chain model.

[0066] Apply a displacement boundary of 72 m to the towing point of the anchor chain model.

[0067] Apply gravity to the soil model with a vertical component set to -10, apply body forces to the drag anchor foundation model with a vertical component of the anchor fluke set to -62605.4 and a vertical component of the anchor shank set to -400000; apply body forces to the anchor chain model with a vertical component set to -37660.

[0068] S7. Assign the material of the cavity element as "void", endow the soil part with the material properties set in step S2, and apply a geostress field to this soil part; set the stress value to 0 with the corresponding vector coordinate being 30, set the stress value to -294000 with the corresponding vector coordinate being 0, and set the lateral coefficient to 1.

[0069] S8. Mesh the established numerical calculation and analysis model and submit it for calculation; the soil model and the cavity are meshed using hexahedral elements, a fine mesh with a mesh size of 0.3 m is used within the penetration area of the drag anchor foundation model, and a coarser mesh with a mesh size of 0.6 m is used in the area outside the penetration area of the drag anchor foundation model; the drag anchor foundation model and the chain link model are meshed using tetrahedral elements with the size determined by the automatic meshing method.

[0070] S9. Post-process, extract the tension at the mooring point of the drag anchor foundation model and the tension at the towing point of the anchor chain model from the historical variable output, and extract the horizontal and vertical displacements of the drag anchor foundation model and the horizontal and vertical displacements at the anchor tip of the drag anchor foundation model from the field variable output.

[0071] As Figure 4 shown, conduct a numerical simulation with the drag anchor - anchor chain as a whole. Compared with the existing research that analyzes the drag anchor alone, the drag anchor foundation model uses solid modeling to highly reproduce the shape of the drag anchor; the chain link adopts a combination form of a cylinder - sphere end. During the movement process, the streamline shape of the sphere is similar to the end of the real chain link, which is beneficial to reducing the resistance received by the anchor chain and highly reproduces the movement form of the anchor chain towing the drag anchor. At the same time, it also solves the problem of using empirical coefficients in the analysis of the drag anchor alone, making the simulation situation consistent with the actual situation.

[0072] Compared with the analysis in existing research through a simplified drag anchor - anchor chain model, the anchor chain is connected by a Join - Rotation combined connector. The Rotation connector provides rotational connection between two nodes, that is, it releases the rotational freedom between the two nodes, and then this connector cannot restrict the displacement freedom between the nodes. Therefore, a connector that can constrain the relative movement between nodes needs to be coupled. The Join connector provides relative position connection between two nodes, that is, it constrains the relative displacements of the two nodes in three directions. So the Join - Rotation combined connector can release the rotational freedom of the two nodes while constraining the relative displacement of the nodes, and can accurately simulate the contact behavior between the drag anchor and the anchor chain, and between the chain links. On this basis, combined with a highly restored drag anchor and an anchor chain in the form of a cylinder - sphere end combination, the movement of the drag anchor driven by the anchor chain is used to truly and accurately describe the interaction between the drag anchor - anchor chain - soil body.

[0073] As Figures 5 - 10 shown, through the sensitivity analysis of the CEL method simulation parameters for the integrated penetration process of the drag anchor - anchor chain, convergence boundaries are obtained for the model size perpendicular to the drag direction, the mesh size in the drag area, and the drag speed, which proves the reliability of the numerical simulation technology proposed in the present invention.

[0074] Those skilled in the art of the present technology can understand that unless otherwise defined, all terms (including technical terms and scientific terms) used here have the same meaning as the general understanding of those of ordinary skill in the art to which this application belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with their meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless defined as such here.

[0075] The meaning of "and / or" as described in this application refers to the situation where each exists alone or both exist simultaneously.

[0076] The meaning of "connection" as described in this application can be a direct connection between components or an indirect connection between components through other components.

[0077] Taking the above - mentioned ideal embodiments of the present invention as an inspiration, through the above - described description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A numerical simulation method for the integrated installation and penetration analysis of a drag anchor and anchor chain, characterized in that The method uses the CEL finite element calculation method in the ABAQUS numerical analysis software, and the method includes the following steps: S1. Establish a numerical calculation and analysis model, which includes a soil model, a drag anchor foundation model, a chain link model, and an anchor chain model; In the soil model, the soil is set as an Euler material, and cavity elements are set on the soil surface; The drag anchor foundation model is modeled using Lagrangian solids and set as a rigid body; The chain link model is set as a rigid body; The anchor chain model is formed by connecting the chain links using a Join-Rotation combination connector; S2. Assign corresponding material properties to each established model; S3. Assemble the numerical calculation and analysis model, set the position and shape of the drag anchor foundation model, and set the position of the anchor chain model; S4. Establish a dynamic display analysis step, and the analysis step includes: a geostress balance analysis step, a step of applying body force to the drag anchor foundation model - anchor chain model, and a step of dragging the drag point of the anchor chain model; S5. Establish the interaction between the drag anchor foundation model, the anchor chain model, and the soil model, and set general contact conditions between the drag anchor foundation model, the anchor chain model, and the soil model; Between the drag anchor foundation model and the anchor chain model, the drag anchor foundation model mooring point and the first chain link of the anchor chain model are connected using a Join-Rotation combination connector, and historical variable output is set for the Join-Rotation combination connector to output the tensile forces at the drag anchor foundation model mooring point and the drag point of the anchor chain model; S6. Define boundary conditions, set the horizontal velocity of the nodes on the outer boundary of the soil elements and cavity elements in the Euler region and set it as an Euler absorption boundary, and set the velocity of the bottom boundary nodes for the soil elements and cavity elements in the Euler region; S7. Set the material assignment of the cavity element as "void", assign the soil the material properties set in step S2, and apply a geostress field to the soil; S8. Mesh the established numerical calculation and analysis model and submit it for calculation; S9. Post-process, extract the displacements and tensile forces in the horizontal and vertical directions at the mooring point of the drag anchor foundation model, extract the tensile force at the drag point, and extract the horizontal and vertical displacements at the anchor tip of the drag anchor foundation model.

2. The numerical simulation method for the integrated installation and penetration analysis of a drag anchor - anchor chain according to claim 1, wherein The chain link model adopts a combination form of a cylinder - spherical end.

3. A numerical simulation method for the integrated installation and penetration analysis of a drag anchor and a chain according to claim 1, characterized in that The height range of the cavity is greater than the heave height during the penetration process of the drag anchor - anchor chain.

4. A numerical simulation method for integrated installation penetration analysis of a drag anchor and an anchor chain according to claim 1, characterized in that In step S2, an ideal elastoplastic constitutive model that satisfies the Mohr-Coulomb yield condition is used to describe the stress-strain relationship of sand.

5. A numerical simulation method for the integrated installation and penetration analysis of a drag anchor and a chain according to claim 1, characterized in that, In step S2, an ideal elastoplastic Tresca constitutive model is used to describe the stress-strain relationship of clay.

6. The numerical simulation method for integrated installation penetration analysis of a drag anchor - anchor chain according to claim 1, characterized in that In step S2, the material properties include one or more of mass density, Young's modulus, Poisson's ratio, friction angle, dilation angle, yield strength, and K0 coefficient.

7. A numerical simulation method for the integrated installation and penetration analysis of a drag anchor - anchor chain according to claim 1, characterized in that, In step S3, set the initial position of the drag anchor foundation model to be at the mud surface, and the initial position of the anchor chain model to be laid flat on the seabed.

8. A numerical simulation method for the integrated installation and penetration analysis of a drag anchor and a chain according to claim 7, characterized in that, There is an angle between the anchor plate plane of the drag anchor foundation model and the mud surface.

9. A numerical simulation method for integrated installation penetration analysis of a drag anchor - anchor chain according to claim 1, characterized in that, In step S6, set the horizontal velocity of the nodes on the outer boundary of the soil elements and cavity elements in the Euler region to 0, and set the velocity of all bottom boundary nodes to 0.

10. A numerical simulation method for the integrated installation and penetration analysis of a drag anchor - anchor chain according to claim 1, characterized in that, In step S8, the soil body model and the cavity element are divided using hexahedron elements. A fine grid is used within the penetration area of the drag anchor foundation model, with a grid size of 0.3 m, and a coarser grid is used in the area outside the penetration area of the drag anchor foundation model, with a grid size of 0.6 m; The drag anchor foundation model and the chain link model are divided using tetrahedron elements.

Images