Dynamic response analysis method of long-span floating bridge based on fluid-structure vehicle-bridge coupling

Abstract

The present invention is a method for analyzing the dynamic response of long-span floating bridges based on fluid-solid vehicle-bridge coupling. The interaction between waves and pontoons is analyzed by computational fluid dynamics methods, the finite element method is used to simulate the upper structure of the floating bridge and vehicle loads, and the connection between the two is established by collaborative simulation, so that the pressure and displacement parameters of the structural solver ABAQUS software and the fluid solver Star‑CCM+ software can be exchanged at each time step, thereby studying the response of discrete pontoon-type offshore floating bridges under the combined action of vehicles and waves, achieving effective analysis of the stress characteristics of the floating bridge structure, and providing a reference for the design and practical application of floating bridge structures. Based on the powerful structural analysis capabilities of ABAQUS software and the excellent fluid analysis advantages of Star‑CCM+ software, as well as the good coupling effect between the two, the present invention realizes the solution of fluid-solid coupling and vehicle-bridge coupling with less computing resources, ensures the calculation accuracy of the numerical model, and provides guidance for the subsequent design and application of long-span floating bridges.

Description

Technical Field

[0001] The present invention belongs to the field of bridge simulation analysis, and in particular relates to a dynamic response analysis method for a long-span floating bridge based on fluid-solid vehicle-bridge coupling. Background Art

[0002] Currently, the methods for solving fluid-structure coupling problems are mainly divided into two categories: (1) direct coupling solution and (2) separation solution; the analysis of vehicle-bridge coupling is divided into three categories: (1) field experiment method, (2) theoretical derivation method, and (3) numerical simulation method.

[0003] For fluid-structure interaction problems, direct coupling methods solve the fluid and structural equations as a unified system, placing high demands on algorithms and requiring strong computational analysis capabilities. Separate solutions employ independent fluid and structural solvers to solve their respective governing equations, approximating the true structural and fluid solutions with a small data exchange interval. For vehicle-bridge interaction problems, field experiments require extensive preparation and are costly. Theoretical derivation methods are often suitable for simple models, while numerical simulations are more economical and applicable. However, existing numerical simulation methods rarely comprehensively consider both vehicle-bridge and fluid-structure interaction. Summary of the Invention

[0004] The purpose of the present invention is to provide a dynamic response analysis method for long-span floating bridges based on fluid-solid vehicle-bridge coupling, aiming to solve the problems of cumbersome modeling and low efficiency in the current comprehensive problems of vehicle-bridge coupling and fluid-solid coupling. Based on the powerful structural analysis function of ABAQUS software and the excellent fluid analysis advantages of Star-CCM+ software, as well as the good coupling effect between the two, the vehicle-bridge fluid-solid coupling solution is achieved with less computing resources, ensuring the calculation accuracy of the numerical model, and providing guidance for the design and practical application of future long-span floating bridges.

[0005] The technical solution for achieving the objectives of the present invention is a method for analyzing the dynamic response of long-span floating bridges based on fluid-structure vehicle-bridge coupling. This method uses computational fluid dynamics to analyze the interaction between waves and pontoons, uses the finite element method to simulate the floating bridge superstructure and vehicle loads, and uses collaborative simulation to establish a connection between the two, enabling the exchange of pressure and displacement parameters at each time step between the structural solver ABAQUS and the fluid solver Star-CCM+. The method specifically includes the following steps:

[0006] Step S1: Create simplified models of the pontoon, main beam, and vehicle components in ABAQUS. The pontoon uses shell elements, the bridge uses beam elements with virtual surfaces on the outside, and the vehicle uses simplified truss spring elements. Set the attribute parameters, export the geometric model of the pontoon, and save it as a .sat file.

[0007] Step S2: Assemble the components in ABAQUS software, set the analysis step and contact parameters, and use optimized spring elements to simulate the coupling relationship between the vehicle and the bridge;

[0008] Step S3: Apply loads, set boundary conditions, and divide the mesh in ABAQUS software to generate the .inp file;

[0009] Step S4: Import the .sat file of the float tank into the Star-CCM+ software to establish the fluid domain boundary and free surface;

[0010] Step S5: Divide the grid in Star-CCM+ software, use a refined grid for the water surface, establish the fluid domain physical model, and set regional conditions;

[0011] Step S6: Setting the co-simulation parameters of Star-CCM+ software and ABAQUS software;

[0012] Step S7: Submit for analysis and calculation in Star-CCM+ software.

[0013] Furthermore, step S1 specifically includes the following steps:

[0014] Step S11: In the component module, a discrete rigid body of three-dimensional line elements and shell elements is established according to the size of the vehicle and the pontoon, a three-dimensional shell element is established according to the size of the bridge, and the connecting beam is a three-dimensional beam element;

[0015] Step S12: In the attribute module, reference points are set at the pontoon and the center of gravity of the vehicle and inertia attributes are assigned, and geometric and material attribute parameters are assigned to the main beam.

[0016] Furthermore, step S2 specifically includes the following steps:

[0017] Step S21: assembling the assembly modules according to the actual working conditions to form a complete floating bridge system;

[0018] Step S22: setting the static general analysis step and the dynamic implicit analysis step in the analysis step module, and limiting the maximum incremental step size of the dynamic implicit analysis step to ensure calculation accuracy;

[0019] Step S23: In the interaction module, the single pontoon and the vehicle are coupled to the reference point respectively, and the connecting beam and the pontoon are connected by means of an MPC beam;

[0020] Step 24: Create a "Hard" Contact normal contact behavior to set up the interaction between the vehicle and the bridge deck.

[0021] Furthermore, step S3 specifically includes the following steps:

[0022] Step S31: setting constraints on the pontoon and main beam in the load module, and applying gravity load to the floating bridge system;

[0023] Step 32: Divide the pontoon, connecting beam and main bridge into corresponding grids in the grid module.

[0024] Furthermore, step S4 specifically includes the following steps:

[0025] Step S41: Import the pontoon model from ABAQUS software and name it Geometry;

[0026] Step 42: Create a new fluid domain external boundary Block in the Star-CCM+ software, perform Boolean operations on the Block and Geometry to obtain the fluid domain named Fluid Domain, and rename each surface; create a new Block for subsequent mesh encryption at the free liquid surface and name it Water.

[0027] Furthermore, step S5 specifically includes the following steps:

[0028] Step S51: assigning Fluid Domain components to regions before meshing, and setting boundary regions for fluid analysis;

[0029] Step S52: Meshing the fluid domain in Star-CCM+ software, creating a new physical model 1 for fluid domain calculation, and creating another physical model 2 for data exchange with ABAQUS software;

[0030] Step 53: Set the properties for the boundary zone, specifying the deformation of all walls as displacement and the external program coupling as Link 1: Zone1.

[0031] Furthermore, step S6 specifically includes the following steps:

[0032] Step S61: Create a new mechanical field Displacement in the external link node, and create a new mechanical field Pressure in the derived field;

[0033] Step 62: Under the Version node, set the Version to Custom, the Load Partner Library option to Specified Library File, select Physics 1 for External Continuum, set the Time Marching Sequence to ABAQUS Leading, and set the Coupling Negotiation option to Constant.

[0034] Furthermore, step S7 specifically includes the following steps:

[0035] Step S71: Before running the collaborative coupling simulation analysis, the Star-CCM+ software program is run separately for 2-3 seconds to eliminate the influence of the initial flow field.

[0036] Compared with the prior art, the present invention has the following significant advantages:

[0037] The initial model of the floating bridge structure was established using ABAQUS software, in which the vehicle and pontoon were established using the method of discretizing rigid bodies using three-dimensional line elements and shell elements, which ensured accuracy while reducing the amount of calculation. The Star-CCM+ software imported the surface mesh to generate the pontoon model, and the surface nodes coupled with the ABAQUS software were reconstructed through the mapper interpolation algorithm to ensure that the coupled surfaces in the two solvers of the collaborative simulation matched. The key to collaborative simulation is data exchange. For the present invention, data exchange means that the structural solver imports forces from the fluid solver, and the fluid solver imports displacements from the structural solver. The present invention achieves efficient vehicle-bridge fluid-solid coupling modeling and analysis through the effective connection of ABAQUS software and Star-CCM+ software. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a flow chart of the dynamic response analysis method of a long-span floating bridge based on fluid-solid vehicle-bridge coupling of the present invention.

[0039] Figure 2 The ABAQUS software floating bridge model provided in the embodiment of the present invention.

[0040] Figure 3 The ABAQUS software vehicle model provided by the embodiment of the present invention.

[0041] Figure 4 The fluid domain model of the Star-CCM+ software provided in the embodiment of the present invention.

[0042] Figure 5 Three grid views of the Star-CCM+ software provided in an embodiment of the present invention; a is a front view, b is a top view, and c is a side view.

[0043] Figure 6 This is the grid refinement graph of the Star-CCM+ software provided in an embodiment of the present invention.

[0044] Figure 7 This is a graphic representation of the pressuer results of the fluid domain in the Star-CCM+ software provided in an embodiment of the present invention.

[0045] Figure 8 Graphs of the first six modal results of a floating bridge in the ABAQUS software provided in an embodiment of the present invention; wherein a is the first-order mode, b is the second-order mode, c is the third-order mode, d is the fourth-order mode, e is the fifth-order mode, and f is the sixth-order mode. DETAILED DESCRIPTION

[0046] The present invention is further described in detail below with reference to the accompanying drawings.

[0047] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] The dynamic response analysis method of a long-span floating bridge based on fluid-structure vehicle-bridge coupling includes the following steps:

[0049] The establishment of floating bridge model using ABAQUS software, such as Figure 2 As shown,

[0050] In the component module of ABAQUS software, the pontoon is modeled as a discrete rigid body of three-dimensional shell elements according to its size. Connecting beam elements are established, which are truncated at the connection points to create a virtual surface to represent the bridge deck. In the property module, mass and moment of inertia are assigned at the center of gravity of the pontoon.

[0051] The establishment of the vehicle model in ABAQUS software, such as Figure 3 As shown,

[0052] In the component module of ABAQUS software, the vehicle body is simplified into a discrete rigid body of three-dimensional line elements according to the size of the vehicle. The front and rear ends of the vehicle are assembled to form the entire vehicle in the assembly module. The mass and moment of inertia are assigned to the center of gravity of the vehicle body in the property module.

[0053] ABAQUS software assembles all components in the assembly module.

[0054] ABAQUS software sets two analysis steps in the analysis step module: the first is a static general analysis step, and the second is an implicit dynamic analysis step. The incremental step is set to an appropriate value to establish a transmission relationship with the Star-CCM+ software.

[0055] ABAQUS software creates a new contact attribute named Int-1 in the interaction module, establishes a rigid foundation for the bottom surface of all pontoons, couples the reference point and the pontoons in the constraint manager module, establishes MPC beam constraints between the pontoons and the connecting beams, and establishes coupling constraints between the connecting beams and the surfaces.

[0056] ABAQUS software applies gravity in the load action module and sets appropriate constraints at both ends of the pontoon and beam.

[0057] The ABAQUS software mesh module divides the mesh for each component.

[0058] Star-CCM+ software fluid domain model, such as Figure 4 As shown, except for the top surface which is the pressure outlet, the other surfaces are velocity inlets.

[0059] In the geometry module of Star-CCM+ software, import the pontoon model from ABAQUS software, create a new Block as the external boundary of the fluid domain, perform Boolean operations on the Block and Geometry to obtain the fluid domain, and rename each surface; create a new Block named Water for subsequent mesh encryption at the free liquid surface.

[0060] In the mesh module of Star-CCM+ software, assign the Fluid Domain component to the region before dividing the mesh; select Fluid Domain from the component list in the Create Automatic Mesh Operation dialog box, and select the Surface Reconstruction and Cut Mesh Cell Generator in sequence; create two new custom controls, one for surface control to refine the surface mesh of the buoyancy tank, and one for volume control to refine the mesh at the free surface, such as Figure 5 As shown in the figure, the front view, top view and side view are shown from top to bottom. The detailed figure of a single pontoon is shown in the figure. Figure 6 shown.

[0061] In the physical model module of Star-CCM+ software, create a new physical model Physics1 for fluid domain calculation, create the Euler phase required for simulation, and then set its material properties; create another physical model named Physics 1 for data exchange with ABAQUS software.

[0062] In the zone module of Star-CCM+ software, boundary conditions are set for the Fluid Domain, the motion of the Fluid Domain is specified as deformation, the VOF wave zone option is specified as force under the physical condition node, field functions are set for all velocity inlet boundaries, field functions are set for all pressure outlet boundaries, the deformation of all walls is specified as displacement, and the external program coupling is specified as Link1:zone1.

[0063] In the coupling module of Star-CCM+ software, create a new mechanical field Displacement, and a new mechanical field Pressure in the exported field. Set the mapper and set the time step and transmission interval to appropriate values ​​to establish a transmission relationship with Star-CCM+ software.

[0064] Under the Version node, set the version to Custom, set the Load Partner Library option to Specified Library File, select Physics 1 for External Continuum, set the Time Advance Sequence to ABAQUS Software Lead, and set the Coupling Negotiation option to Constant; specify the ABAQUS software library and executable name as specific files in the ABAQUS software folder.

[0065] Run Star-CCM+ software, generate coupling result file, save it as .sim, Figure 7This is a graph of the force results of the pontoon under the action of wave forces in the fluid domain in the Star-CCM+ software. The results perform well while improving the calculation efficiency.

[0066] Run Star-CCM+ software, generate coupling result file, save it as .odb, Figure 8 The following are the graphics of the 1st to 6th modal dynamic response results of the floating bridge under wave force in ABAQUS software. The results of the first six modes are in good agreement with the refined model, and the computational efficiency of this modeling method is greatly improved.

[0067] The present invention realizes efficient and accurate modeling and analysis of vehicle-bridge coupling and fluid-solid coupling through the effective connection of ABAQUS software and Star-CCM+ software.

[0068] The above embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work shall fall within the scope of protection of the present invention.

Claims

1. A dynamic response analysis method for a long-span floating bridge based on fluid-solid vehicle-bridge coupling, characterized in that: This method uses computational fluid dynamics to analyze the interaction between waves and pontoons, employs the finite element method to simulate the bridge superstructure and vehicle loads, and uses collaborative simulation to establish a connection between the two, enabling the exchange of pressure and displacement parameters at each time step between the structural solver ABAQUS and the fluid solver Star-CCM+. The method specifically includes the following steps: Step S1: Create simplified models of the pontoon, main beam, and vehicle components in ABAQUS. The pontoon uses shell elements, the bridge uses beam elements with virtual surfaces on the outside, and the vehicle uses simplified truss spring elements. Set the attribute parameters, export the geometric model of the pontoon, and save it as a .sat file. Step S2: Assemble the components in ABAQUS software, set the analysis step and contact parameters, and use optimized spring elements to simulate the coupling relationship between the vehicle and the bridge; Step S3: Apply loads, set boundary conditions, and divide the mesh in ABAQUS software to generate the .inp file; Step S4: Import the .sat file of the float tank into the Star-CCM+ software to establish the fluid domain boundary and free surface; Step S5: Divide the grid in Star-CCM+ software, use a refined grid for the water surface, establish the fluid domain physical model, and set regional conditions; Step S6: Setting the co-simulation parameters of Star-CCM+ software and ABAQUS software; Step S7: Submit for analysis and calculation in Star-CCM+ software.

2. The method according to claim 1, characterized in that Step S1 specifically includes the following steps: Step S11: In the component module, a discrete rigid body of three-dimensional line elements and shell elements is established according to the size of the vehicle and the pontoon, a three-dimensional shell element is established according to the size of the bridge, and the connecting beam is a three-dimensional beam element; Step S12: In the attribute module, reference points are set at the pontoon and the center of gravity of the vehicle and inertia attributes are assigned, and geometric and material attribute parameters are assigned to the main beam.

3. The method according to claim 2, characterized in that Step S2 specifically includes the following steps: Step S21: assembling the assembly modules according to the actual working conditions to form a complete floating bridge system; Step S22: setting the static general analysis step and the dynamic implicit analysis step in the analysis step module, and limiting the maximum incremental step size of the dynamic implicit analysis step to ensure calculation accuracy; Step S23: In the interaction module, the single pontoon and the vehicle are coupled to the reference point respectively, and the connecting beam and the pontoon are connected by means of an MPC beam; Step 24: Create a "Hard" Contact normal contact behavior to set up the interaction between the vehicle and the bridge deck.

4. The method according to claim 3, characterized in that Step S3 specifically includes the following steps: Step S31: setting constraints on the pontoon and main beam in the load module, and applying gravity load to the floating bridge system; Step 32: Divide the pontoon, connecting beam and main bridge into corresponding grids in the grid module.

5. The method according to claim 4, characterized in that Step S4 specifically includes the following steps: Step S41: Import the pontoon model from ABAQUS software and name it Geometry; Step 42: Create a new fluid domain external boundary Block in the Star-CCM+ software, perform Boolean operations on the Block and Geometry to obtain the fluid domain named Fluid Domain, and rename each surface; create a new Block for subsequent mesh encryption at the free liquid surface and name it Water.

6. The method according to claim 5, characterized in that Step S5 specifically includes the following steps: Step S51: assigning Fluid Domain components to regions before meshing, and setting boundary regions for fluid analysis; Step S52: Meshing the fluid domain in Star-CCM+ software, creating a new physical model 1 for fluid domain calculation, and creating another physical model 2 for data exchange with ABAQUS software; Step 53: Set the properties for the boundary zone, specifying the deformation of all walls as displacement and the external program coupling as Link 1: Zone1.

7. The method according to claim 6, characterized in that Step S6 specifically includes the following steps: Step S61: Create a new mechanical field Displacement in the external link node, and create a new mechanical field Pressure in the derived field; Step 62: Under the Version node, set the Version to Custom, the Load Partner Library option to Specified Library File, select Physics 1 for External Continuum, set the Time Marching Sequence to ABAQUS Leading, and set the Coupling Negotiation option to Constant.

8. The method according to claim 7, characterized in that Step S7 specifically includes the following steps: Step S71: Before running the collaborative coupling simulation analysis, the Star-CCM+ software program is run separately for 2-3 seconds to eliminate the influence of the initial flow field.

Images