Axle collision simulation method and system

Abstract

The invention discloses an axle collision analogue simulation method and system. The system comprises a model construction module and an analogue simulation module. The model construction module constructs an ultrahigh vehicle model and a prestressed concrete bridge model. The reinforcing steel bars of the prestressed concrete model are in fluid-solid coupling contact with the concrete, so that impact force borne by the concrete after a vehicle impacts a bridge is accurately transmitted to the reinforcing steel bars, a foundation is laid for applying a prestressed load to the prestressed concrete bridge model and carrying out collision simulation, and the stress performance of the reinforced concrete is truly reflected. Therefore, the accuracy of the axle collision analogue simulation result is improved. And the analogue simulation module calculates a pre-stress value by adopting an equivalent cooling algorithm according to the temperature value, and applies a pre-stress load to the pre-stressed concrete bridge model according to the pre-stress value. And through the ultrahigh vehicle model and the prestressed concrete bridge model, an axle collision simulation scene is constructed for collision simulation, and the dynamic response of the bridge in the vehicle collision process is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of design optimization or simulation using finite element method, and in particular to a vehicle bridge collision simulation method and system. Background Art

[0002] Since vehicle-bridge collision accidents occur from time to time, it is of great significance to analyze the dynamic response of the bridge during the vehicle-bridge collision process. However, the manufacturing cost of vehicles and bridges is relatively high, and currently most vehicle-bridge collisions are analyzed by simulation. For example, the patent application with publication number CN114417662A discloses a single thin-walled continuous rigid frame pier collision simulation method, which constructs a bridge finite element model and a vehicle model for collision simulation analysis to obtain the dynamic response during the vehicle-bridge collision process, thereby evaluating the damage to the pier. However, this technical solution does not take into account the prestressed load of the bridge when constructing the bridge finite element model, resulting in the constructed bridge finite element model being unable to truly reflect the stress performance of the bridge reinforced concrete, thereby affecting the accuracy of the simulation results. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention proposes a vehicle-bridge collision simulation method and system, which can improve the accuracy of vehicle-bridge collision simulation results. The specific technical solution is as follows:

[0004] In a first aspect, a vehicle bridge collision simulation method is provided. In a first implementable manner of the first aspect, the method includes:

[0005] Construct a super-high vehicle model and a prestressed concrete bridge model, in which the fluid-solid coupling contact between the steel bars and the concrete is adopted;

[0006] A prestressed load is applied to the prestressed concrete bridge model according to an equivalent cooling algorithm, and the super-high vehicle model is introduced into the prestressed concrete bridge model to which the prestressed load is applied for collision simulation.

[0007] In combination with the first implementable manner of the first aspect, in a second implementable manner of the first aspect, constructing the prestressed concrete bridge model includes: adopting surface-to-surface contact between the main beam and the support in the prestressed concrete bridge model.

[0008] In combination with the first implementable method of the first aspect, in a third implementable method of the first aspect, constructing the prestressed concrete bridge model includes: using a continuous surface cap model to simulate the material properties of the main beam and the support in the prestressed concrete bridge model.

[0009] In combination with the first implementable manner of the first aspect, in a fourth implementable manner of the first aspect, constructing the prestressed concrete bridge model includes: using the MAT_PLASTIC_KINEMATIC model to simulate the temperature characteristics of the prestressed steel bars in the prestressed concrete bridge model.

[0010] In combination with the first implementable manner of the first aspect, in a fifth implementable manner of the first aspect, constructing the prestressed concrete bridge model includes:

[0011] The MAT_ELASTIC_PLASTIC_THERMAL model is used to simulate the movable characteristics of the steel bars in the prestressed concrete bridge model under impact loads.

[0012] In combination with the first implementable manner of the first aspect, in a sixth implementable manner of the first aspect, constructing the super-high vehicle model includes: using a MAT_PTECEWISE_LINEAR_PLASTICITY model to simulate the change in strain of the car body material in the super-high vehicle model over time under an impact load.

[0013] In combination with the first implementable manner of the first aspect, in a seventh implementable manner of the first aspect, constructing the super-high vehicle model includes: using shell elements to mesh the car body in the super-high vehicle model.

[0014] In combination with the seventh implementable manner of the first aspect, in an eighth implementable manner of the first aspect, constructing the super-high vehicle model includes: performing secondary meshing on the meshed carriage.

[0015] In a second aspect, a vehicle-bridge collision simulation system is provided, comprising:

[0016] A model building module, configured to build a super-high vehicle model and a prestressed concrete bridge model, in which a fluid-solid coupling contact is adopted between steel bars and concrete;

[0017] The simulation module is configured to apply a prestressed load to the prestressed concrete bridge model according to an equivalent cooling algorithm, and import the super-high vehicle model into the prestressed concrete bridge model to which the prestressed load is applied for collision simulation.

[0018] Beneficial effect: By adopting the vehicle-bridge collision simulation method and system of the present invention, by setting the fluid-solid coupling contact between the steel bars and the concrete in the prestressed concrete bridge model, the impact force exerted on the concrete after the vehicle hits the bridge can be accurately transmitted to the steel bars, laying the foundation for the subsequent application of prestressed loads to the prestressed concrete bridge model and collision simulation, so as to truly reflect the stress performance of reinforced concrete, thereby improving the accuracy of the vehicle-bridge collision simulation results. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation of the present invention, the following will briefly introduce the drawings required for use in the specific implementation. In all the drawings, each element or part is not necessarily drawn according to the actual scale.

[0020] Figure 1 A flow chart of a vehicle-bridge collision simulation method provided by an embodiment of the present invention;

[0021] Figure 2 A system block diagram of a vehicle-bridge collision simulation system provided by an embodiment of the present invention;

[0022] Figure 3 This is a structural diagram of the constructed prestressed concrete bridge model;

[0023] Figure 4 This is a schematic diagram of the structure of the constructed super-high vehicle model;

[0024] Figure 5 A schematic diagram of the constructed vehicle-bridge collision simulation scenario;

[0025] Figure 6 To adopt Figure 1 Schematic diagram of simulation results obtained by the vehicle-bridge collision simulation method shown. DETAILED DESCRIPTION

[0026] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0027] like Figure 1 The flowchart of the bridge collision simulation method shown in FIG. 1 includes:

[0028] Step 1, constructing a super-high vehicle model and a prestressed concrete bridge model, in which a fluid-solid coupling contact is adopted between the steel bars and the concrete;

[0029] Step 2: applying a prestressed load to the prestressed concrete bridge model according to an equivalent cooling algorithm, and importing the super-high vehicle model into the prestressed concrete bridge model to which the prestressed load is applied for collision simulation.

[0030] Specifically, first, the HyperMesh software can be used to build a super-high vehicle model and a prestressed concrete bridge model for vehicle-bridge collision simulation. When building the prestressed concrete model, the steel bars and concrete can be set to fluid-solid coupling contact so that the impact force on the concrete after the vehicle hits the bridge is accurately transmitted to the steel bars, laying the foundation for the subsequent application of prestressed loads to the prestressed concrete bridge model and collision simulation, so as to truly reflect the stress performance of reinforced concrete, thereby improving the accuracy of the vehicle-bridge collision simulation results.

[0031] Then, the constructed prestressed concrete model can be imported into the LS-DYNA software, and the parameters of the steel bars in the prestressed concrete model and the temperature value that needs to be reduced can be set. The LS-DYNA software can calculate the prestress value of the steel bars using the equivalent cooling algorithm according to the temperature value that needs to be reduced. The relationship between the prestress value and the temperature value is as follows:

[0032]

[0033] Among them, ΔT is the temperature value to be reduced, N is the prestress value, α is the linear expansion coefficient of the steel bar, E is the elastic modulus of the steel bar, and A is the cross-sectional area of ​​the steel bar. The equivalent cooling method can effectively simulate the prestress of complex prestressed concrete structures. It is easy to operate and has a wide range of applications. The engineering example verification shows that the calculation accuracy is high. It can provide a reference for the equivalent simulation of prestress in the finite element calculation of prestressed concrete structures, and further improve the accuracy of the vehicle-bridge collision simulation results.

[0034] LS-DYNA software can apply prestress load to the prestressed concrete bridge model according to the prestress value. Then import the constructed super-high vehicle model into LS-DYNA software, and then build a prestressed concrete bridge model. Figure 5 The vehicle-bridge collision simulation scenario shown in the figure is used to perform collision simulation to obtain the dynamic response of the bridge during the vehicle collision process, such as Figure 6 shown.

[0035] In this embodiment, optionally, constructing the prestressed concrete bridge model includes: adopting surface-to-surface contact between the main beam and the support in the prestressed concrete bridge model.

[0036] Specifically, when using HyperMesh software to build a prestressed concrete bridge model, a 4-piece small box girder bridge model with a standard span of 25m can be established, the bridge width is 12m, and the overall weight is 344t. Concrete with a strength grade of C50 is used. Prestressed steel bars use high-strength low-relaxation steel strands with a nominal diameter of Φ15.2mm, and the tension control stress is 1395MPa. Ordinary steel bars (including longitudinal steel bars and stirrups) use R235 steel bars with nominal diameters of 8 and 10mm and HRB335 steel bars with nominal diameters of 12, 20, 22, and 25mm.

[0037] Since the bottom of the bridge's main beam and the top of the support are in plane-to-plane contact, selecting surface-to-surface contact can more accurately simulate the force behavior of the structure and obtain more accurate support reaction forces. To this end, the bridge's main beam and support can be set to automatic surface-to-surface contact. In LS-DYNA software, this can be achieved using the keyword CONTACT_AUTOMATIC_SURFACE_TO_SURFACE.

[0038] In this embodiment, optionally, constructing the prestressed concrete bridge model includes: using a continuous surface cap model to simulate material properties of the main beam and the support in the prestressed concrete bridge model.

[0039] Specifically, when constructing the prestressed concrete model, an 8-node single-point integral 3D solid unit can be used to simulate the main beam concrete and support. The unit grid size can be set to 50 mm, and the material properties use the *MAT_CSCM_CONCRETE keyword to simulate the continuous smooth cap model of the elastic-plastic deformation and failure behavior of concrete under low-speed impact. The continuous smooth cap model can truly simulate the stress behavior of the bridge structure after the concrete material is hit. This constitutive model has been confirmed by many foreign scholars to be the most accurate in simulating the plastic deformation behavior under impact, further improving the accuracy of the vehicle-bridge collision simulation results.

[0040] In this embodiment, optionally, constructing the prestressed concrete bridge model includes:

[0041] The MAT_PLASTIC_KINEMATIC model is used to simulate the temperature characteristics of prestressed steel bars in the prestressed concrete bridge model.

[0042] Specifically, when constructing the prestressed concrete model, the steel bars can be divided using the Hughes-Liu beam element with 2×2 Gaussian integral, the mesh size can be set to 100 mm, and the prestressed steel bars are simulated using the *MAT_ELASTIC_PLASTIC_THERMAL keyword to consider the influence of the material temperature characteristics.

[0043] In this embodiment, optionally, constructing the prestressed concrete bridge model includes:

[0044] The MAT_ELASTIC_PLASTIC_THERMAL model is used to simulate the movable characteristics of the steel bars in the prestressed concrete bridge model under impact loads.

[0045] Specifically, when constructing a prestressed concrete model, the MAT_PLASTIC_KINEMATIC keyword can be used to simulate the dynamic characteristics of ordinary steel bars under impact loads. The MAT_ELASTIC_PLASTIC_THERMAL model can simulate the strain rate effect of ordinary steel bar materials after the bridge structure is impacted. The strain rate effect must be considered for impact and shock loads. In this way, the elastic-plastic deformation behavior of the structure after the impact will be simulated more accurately, which can reflect the actual force transmission during the impact process and further improve the accuracy of the vehicle-bridge collision simulation results. The final prestressed concrete bridge model is as follows: Figure 3 as shown.

[0046] In this embodiment, optionally, constructing the super-high vehicle model includes:

[0047] The MAT_PTECEWISE_LINEAR_PLASTICITY model is used to simulate the change of strain of the car body material in the super-high vehicle model under impact load over time.

[0048] Specifically, when constructing the super-high vehicle model, a standard double-axle truck finite element model can be used, with a total length of 8.54m, a maximum width of 2.44m, and a wheelbase of 5.29m. The compartment material can use the *MAT_PTECEWISE_LINEAR_PLASTICITY keyword of kinematic strengthening to simulate the change of material strain over time under impact load.

[0049] The degree of damage to the bridge and the vehicle after the final impact needs to be evaluated with reference to the plastic deformation of the vehicle compartment after the impact. The MAT_PTECEWISE_LINEAR_PLASTICITY model can accurately simulate the changes in the vehicle compartment after the impact with the impact load, and the strain changes of the compartment, which can provide a reference for the damage status assessment of the compartment.

[0050] In this embodiment, optionally, constructing the super-high vehicle model includes: using shell elements to mesh the car body in the super-high vehicle model.

[0051] Specifically, when constructing a super-high vehicle model, since the thickness of the vehicle compartment is small, it is most appropriate to use shell elements based on the Belytschko-Tsay algorithm to mesh the compartment of the super-high vehicle model.

[0052] In this embodiment, optionally, constructing the super-high vehicle model includes: performing secondary meshing on the meshed carriage.

[0053] Specifically, in order to improve the efficiency and accuracy of the simulation, after the car body is meshed using shell elements, the mesh of the divided car body can be meshed again, and the minimum unit size can be set to 50mm. Figure 4 shown.

[0054] like Figure 2 The system block diagram of the bridge collision simulation system shown in FIG. 1 includes:

[0055] A model building module, configured to build a super-high vehicle model and a prestressed concrete bridge model, in which a fluid-solid coupling contact is adopted between steel bars and concrete;

[0056] The simulation module is configured to apply a prestressed load to the prestressed concrete bridge model according to an equivalent cooling algorithm, and import the super-high vehicle model into the prestressed concrete bridge model to which the prestressed load is applied for collision simulation.

[0057] Specifically, the simulation system is composed of a model building module and a simulation module. Among them, the model building module can build a super-high vehicle model and a prestressed concrete bridge model for vehicle-bridge collision simulation. When building a prestressed concrete model, the model building module can set the fluid-solid coupling contact between the steel bars and the concrete, so that the impact force of the concrete after the vehicle hits the bridge can be accurately transmitted to the steel bars, laying the foundation for the subsequent application of prestressed loads to the prestressed concrete bridge model and collision simulation, so as to truly reflect the force performance of reinforced concrete, thereby improving the accuracy of the vehicle-bridge collision simulation results.

[0058] The simulation module can calculate the prestress value of the steel bar using an equivalent cooling algorithm according to the temperature value that needs to be lowered, and can apply prestress load to the prestressed concrete bridge model according to the prestress value. Then, through the constructed super-high vehicle model and prestressed concrete bridge model, a vehicle-bridge collision simulation scene is constructed for collision simulation to obtain the dynamic response of the bridge during the vehicle collision process.

[0059] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A vehicle-bridge collision simulation method, characterized in that: include: Construct a super-high vehicle model and a prestressed concrete bridge model, in which the fluid-solid coupling contact between the steel bars and the concrete is adopted; A prestressed load is applied to the prestressed concrete bridge model according to an equivalent cooling algorithm, and the super-high vehicle model is introduced into the prestressed concrete bridge model to which the prestressed load is applied for collision simulation.

2. The vehicle-bridge collision simulation method according to claim 1, characterized in that: Constructing the prestressed concrete bridge model includes: adopting surface-to-surface contact between the main beam and the support in the prestressed concrete bridge model.

3. The vehicle-bridge collision simulation method according to claim 1, characterized in that: Constructing the prestressed concrete bridge model includes: using a continuous surface cap model to simulate the material properties of the main beam and the support in the prestressed concrete bridge model.

4. The vehicle-bridge collision simulation method according to claim 1, characterized in that: Constructing the prestressed concrete bridge model includes: using the MAT_PLASTIC_KINEMATIC model to simulate the temperature characteristics of the prestressed steel bars in the prestressed concrete bridge model.

5. The vehicle-bridge collision simulation method according to claim 1, characterized in that: Constructing the prestressed concrete bridge model includes: using the MAT_ELASTIC_PLASTIC_THERMAL model to simulate the activity characteristics of the steel bars in the prestressed concrete bridge model under impact loads.

6. The vehicle-bridge collision simulation method according to claim 1, characterized in that: Constructing the super-high vehicle model includes: using the MAT_PTECEWISE_LINEAR_PLASTICITY model to simulate the change of strain of the car body material in the super-high vehicle model under impact load over time.

7. The vehicle-bridge collision simulation method according to claim 1, characterized in that: Constructing the super-high vehicle model includes: using shell elements to mesh the compartments in the super-high vehicle model.

8. The vehicle bridge collision simulation method according to claim 7, characterized in that: Constructing the super-high vehicle model includes: performing secondary grid division on the grid-divided carriage.

9. A vehicle-bridge collision simulation system, characterized in that: include: A model building module, configured to build a super-high vehicle model and a prestressed concrete bridge model, in which a fluid-solid coupling contact is adopted between steel bars and concrete; The simulation module is configured to apply a prestressed load to the prestressed concrete bridge model according to an equivalent cooling algorithm, and import the super-high vehicle model into the prestressed concrete bridge model to which the prestressed load is applied for collision simulation.

Images