Prefabricated guardrail optimization design simulation method, system and equipment

Abstract

The invention relates to the technical field of guardrail safety optimization design, in particular to a guardrail manufacturing optimization design simulation method, system and equipment. According to the prefabricated guardrail optimization design simulation scheme provided by the invention, fine modeling is performed on the vehicle and the guardrail through the three-dimensional modeling software, various detail features of an actual structure are completely restored, and then a self-adaptive simulation calculation algorithm and a parallel calculation technology are adopted; simulation calculation can be automatically adjusted according to the physical phenomenon in the collision process and the stability requirement of numerical calculation, the calculation efficiency is remarkably improved on the premise that the calculation precision is guaranteed, the simulation calculation time is shortened, the requirement for rapid iterative calculation in the engineering design and optimization process is met, and the method is suitable for large-scale popularization and application. An efficient technical means is provided for solving complex engineering problems, and the motion trail and collision deformation of the vehicle after collision are accurately simulated.

Description

Technical Field

[0001] This application relates to the technical field of safety optimization design of guardrails, and particularly relates to a simulation method, system and device for optimizing the design of precast guardrails. Background Art

[0002] With the continuous increase in the number of automobiles and the increasing complexity of the road traffic environment, the collision accidents between automobiles and guardrails occur frequently, seriously threatening the safety of personnel's lives and the integrity of road infrastructure. Therefore, in-depth study of the collision performance between automobiles and guardrails and the proposal of effective guardrail design and improvement methods are of great significance for improving the road safety level, reducing the severity of accidents, and improving engineering efficiency.

[0003] With the development of computer technology and numerical simulation methods, it has become possible and necessary to use simulation means to study the collision process between vehicles and guardrails. There are many limitations in traditional vehicle-guardrail collision simulation technology, such as inaccurate simulation calculations, single calculation method, low efficiency, and inaccurate result analysis, etc., which cannot well meet the requirements of modern traffic engineering for accurate assessment of collision safety performance, optimization design of guardrails, and improvement of safety standards, resulting in the designed guardrails not being able to meet the actual project well. For example, a physical project of the same scale will be built within a certain period of time but cannot meet the project requirements and will be demolished, resulting in huge construction costs and serious waste of resources, and seriously affecting engineering efficiency. Summary of the Invention

[0004] Based on this, in view of the above problems, this application proposes a simulation scheme for optimizing the design of precast guardrails, aiming to use advanced simulation technology to simulate the collision process between automobiles and guardrails, analyze the collision dynamics behavior, and provide a scientific basis for the design and optimization of guardrails.

[0005] This application provides a simulation method for optimizing the design of precast guardrails on the one hand. The method includes:

[0006] Establish finite element models of multiple types of vehicles according to the sizes and characteristics of different types of vehicles;

[0007] Establish a finite element model of the guardrail according to the current guardrail structure design;

[0008] Fit to obtain the corresponding material constitutive relationship and input it into the model as material property parameters;

[0009] Set simulation contact and boundary conditions, establish a dynamic equation for vehicle-guardrail collision simulation;

[0010] Extract preset key nodes, and adaptively adjust the simulation calculation according to the deformation change rate of the key nodes to obtain the simulation results;

[0011] Output the simulation results and correct and optimize the guardrail structure design.

[0012] Preferably, the adaptive adjustment of the simulation calculation according to the deformation change rate of the key node includes:

[0013] Obtain the total load vector of each node at the current time step, substitute it into the dynamic equation to obtain the node acceleration vector, and update the node velocity vector and displacement vector;

[0014] Calculate the strain tensor of each finite element according to the displacement of each node, and determine the deformation size of each finite element;

[0015] Calculate the deformation change rate R of the current key node n ;

[0016] If the deformation change rate of the key node is greater than the first preset value, adjust the next simulation time step:

[0017]

[0018] where, △t n+1 、△t n are the next and current simulation time steps respectively, α 1 is the adjustment coefficient, and α 1 <1;

[0019] Continue the simulation calculation for the next time step until the simulation time ends.

[0020] Furthermore, the method further includes:

[0021] If the deformation change rate of the key node is less than the second preset value, adjust the next simulation time step:

[0022]

[0023] where, w max is the highest natural vibration frequency of the system, α 2 is the adjustment coefficient, and α 2 >1.

[0024] Preferably, calculating the deformation change rate R of the current key node n , includes:

[0025]

[0026] where, m is the number of key nodes, u j,n 、u j,n-1 are the displacement magnitudes of the jth key node at the current time step and the previous time step respectively, f j,n 、f j,n-1are the magnitudes of the contact forces at the current time step and the previous time step of the j-th critical node respectively, and γ is the weight parameter.

[0027] Further, the method further includes:

[0028] Detect whether each slave point penetrates the master surface. If it penetrates, calculate the interface contact force F between the current slave node and the penetrated master surface i , the contact force F i satisfies:

[0029]

[0030] where δ i is the penetration depth of the i-th penetrated slave node, k 0 is the initial penalty stiffness parameter, and δ is the penetration depth threshold th , and λ and θ are the corresponding adjustment coefficients respectively;

[0031] Use the contact force as the external load vector, and superimpose the internal load vector corresponding to the node to obtain the total load vector.

[0032] Further, the method includes:

[0033] If the deformation change rate of the critical node is less than the second preset value and lasts for a preset number of time steps, then adjust and switch to the implicit method to solve the dynamic equation.

[0034] Further, the method further includes:

[0035] Judge whether the structural stress state reaches yield. If not, process it according to the constitutive of linear elastic materials;

[0036] If the stress exceeds the yield strength, calculate the stress-strain in the structure according to the constitutive of plastic or brittle deformation.

[0037] The second aspect of the present application provides a precast guardrail optimization design simulation system, and the system includes:

[0038] A model establishment unit, configured to establish a finite element model of multiple types of vehicles according to the sizes and characteristics of different types of vehicles; and establish a finite element model of the guardrail according to the current guardrail structure design;

[0039] A parameter setting unit, configured to fit the corresponding material constitutive relationship and input it into the model as material property parameters;

[0040] A simulation initial setting unit, configured to set simulation contact and boundary conditions, and establish a dynamic equation to perform a vehicle-guardrail collision simulation;

[0041] A simulation calculation unit, configured to extract preset key nodes, adaptively adjust simulation calculations according to the deformation change rate of the key nodes, and obtain a simulation result;

[0042] Result output and optimization, configured to output the simulation result and correct and optimize the guardrail structure design.

[0043] A computer-readable storage medium is provided in a third aspect of the present application, storing a computer program, which, when executed by a processor, causes the processor to execute the steps of the method described in any one of the above.

[0044] A computer terminal device is provided in a fourth aspect of the present application, including a memory and a processor, the memory storing a computer program, which, when executed by the processor, causes the processor to execute the steps of the method described in any one of the above.

[0045] The precast guardrail optimization design simulation solution provided above in the present application finely models the vehicle and the guardrail through 3D modeling software, completely restoring various detailed features of the actual structure, and then adopting an adaptive simulation calculation algorithm and parallel computing technology, which can automatically adjust simulation calculations according to physical phenomena during the collision process and stability requirements of numerical calculations, significantly improving the calculation efficiency on the premise of ensuring calculation accuracy, shortening the simulation calculation time, meeting the requirements of rapid iterative calculations in the engineering design and optimization process, providing an efficient technical means for solving complex engineering problems, and accurately simulating the movement trajectory and collision deformation of the vehicle after collision.

[0046] Furthermore, by adopting a high-precision model construction technology and an optimized contact algorithm, the mechanical interaction during the collision between the vehicle and the guardrail can be more accurately simulated, thereby further improving the accuracy of predicting the movement trajectory of the vehicle after collision, including parameters such as the displacement, speed, acceleration, and attitude change of the vehicle, enabling the accurate simulation of the deformation mode and degree of the guardrail during the collision process, and significantly reducing the error from the results of real vehicle collision tests, providing technical support for traffic safety assessment and optimization design. Description of the Drawings

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0048] Among them:

[0049] Figure 1 It is a flowchart of the precast guardrail optimization design simulation method in an embodiment;

[0050] Figure 2 Schematic diagram of a finite element model of multi-type vehicles established for the dimensions and characteristics of different actual vehicle types in an embodiment;

[0051] Figure 3 (a) Comparison diagram of the simulation results and test results of a car colliding with a guardrail in an embodiment, Figure 3 (b) Deformation diagram of the simulation results and test results of a car colliding with a large bus against a guardrail in an embodiment, Figure 3 (c) Comparison diagram of the test and computer simulation results of colliding with a reinforced concrete guardrail in an embodiment;

[0052] Figure 4 Structural block diagram of a precast guardrail optimization design simulation system in an embodiment;

[0053] Figure 5 Structural block diagram of a computer device in an embodiment. Specific embodiments

[0054] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0055] The terms "including", "comprising" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned accompanying drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products or devices. In the terms in the claims, specification and specification drawings of this application, relational terms such as "first" and "second" are only used to distinguish one entity / operation / object from another entity / operation / object, and do not necessarily require or imply any such actual relationship or order between these entities / operations / objects.

[0056] Referring to "embodiment" herein means that a specific feature, structure or characteristic described in conjunction with the embodiment may be included in at least one embodiment of this application. The phrase appears in various displacements in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

[0057] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. And although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0058] In one embodiment, as Figure 1 shown, it is a flowchart of a simulation method for optimizing the design of a prefabricated guardrail according to the present application. The method includes:

[0059] S10. Establish finite element models of multiple types of vehicles according to the sizes and characteristics of different types of vehicles.

[0060] Specifically, use high-precision finite element software (such as ABAQUS, ANSYS, etc.) to construct the geometric model of the vehicle, accurately describe the external contour of the vehicle, including key components such as the body, bumper, and wheels, and reasonably simplify the vehicle model, removing some detailed features that have little impact on the collision process, such as body decorative lines, etc., to reduce the amount of calculation.

[0061] Establish finite element models of multiple types of vehicles according to the actual sizes and characteristics of different types of vehicles, divide the vehicle models into finite element meshes, and adopt different element types and sizes according to the structural characteristics and mechanical properties of each component of the vehicle. The vehicle models include the fine cross-sectional shapes and minute structures of the connection parts in the vehicle engine compartment, the special structure of the chassis, and the guardrail.

[0062] Furthermore, the present application uses an adaptive mesh generation method to mesh the vehicle and guardrail models. In key areas where collisions may occur, such as the contact area between the vehicle bumper and the guardrail, the columns and beams of the guardrail that are impacted, etc., set a finer mesh size to improve the calculation accuracy of these areas. For some areas where the strain change is small, appropriately coarsen the mesh to reduce the amount of calculation.

[0063] Since the body structure is mainly thin-walled metal parts, the element type is mainly the quadrilateral single-point integration shell element that is good at large deformation. To obtain good elements, control the warping degree of the quadrilateral element to be less than 15, the aspect ratio to be less than 4, the maximum angle to be less than 135°, the minimum angle to be greater than 45°, the number of triangular elements to be within 5%, and the minimum characteristic length to be controlled at about 5 mm. The various parts of the body are mainly connected by spot welding, and the doors and the car body are connected by hinge point elements.

[0064] As Figure 2 shown, in an embodiment of the present application, it is a schematic diagram of finite element models of multiple types of vehicles established according to the sizes and characteristics of different actual vehicle types, including cars, medium and large buses, trucks, etc.

[0065] S11. Establish a finite element model of the guardrail according to the current guardrail structure design.

[0066] Specifically, establish a corresponding finite element model according to the structure of the current precast guardrail design, and describe in detail the structures such as the columns and crossbeams of the guardrail, and perform finite element mesh division on the guardrail model. Steel and concrete are the main structural materials of the concrete guardrail. The accuracy of the simulation parameters of the guardrail is verified through research. In the simulation model, the steel bars are simulated with elastoplastic materials. In the LS-DYNA model, the concrete material is simulated with Mat159 material, and the main input parameters are the compressive strength, aggregate diameter, and some control parameters. The *CONSTRAINED_LAGRANGE_IN_SOLID keyword is used to constrain between the concrete and the steel bars.

[0067] S12. Fit to obtain the corresponding material constitutive relationship and input it as a material property parameter into the model.

[0068] Specifically, conduct comprehensive material performance tests on the materials used for the vehicle and the guardrail. For metal materials, in addition to measuring conventional parameters such as elastic modulus, Poisson's ratio, and density, it is also necessary to obtain the stress-strain curve of the material through tensile tests, compression tests, bending tests, etc., and determine key non-linear material parameters such as yield strength, tensile strength, and fracture strain. For composite materials or other special materials, special test methods are used to obtain their equivalent material performance parameters.

[0069] Accurately assign the measured material parameters to the corresponding model components. In the finite element software, create special material constitutive models for different materials (such as Johnson-Cook model, Cowper-Symons model, which can consider the influence of strain rate effect on material performance and has good applicability in high-speed collision simulation), and input the material parameters into the model.

[0070] Select a suitable constitutive model for fitting according to the type of material and the characteristics of the test data. For linearly elastic materials, the linear relationship σ = Eε (where σ is stress, ε is strain, and E is elastic modulus) can be used for fitting.

[0071] For materials with plastic deformation, such as the bilinear model or power-law hardening model in the elastoplastic model. Taking the bilinear elastoplastic model as an example, in the elastic stage, when the strain exceeds the yield strain εy, the stress-strain relationship becomes:

[0072] σ = σ y +E p (ε - ε p ),

[0073] Among them, σy is the yield stress and Ep is the plastic modulus. By methods such as least squares fitting of test data, these model parameters can be determined, thereby establishing the constitutive relationship of the material.

[0074] Furthermore, in an embodiment of the present application, the method further includes: determining whether the structural stress state reaches yield. If not, it is processed according to the constitutive of linear elastic materials; if the stress exceeds the yield strength, the stress-strain in the structure is calculated according to the constitutive of plastic or brittle deformation.

[0075] S13. Set the simulation contact and boundary conditions, and establish the dynamic equation for the vehicle-guardrail collision simulation.

[0076] Specifically, the solution of the present application defines in detail the contact relationship between the vehicle and the guardrail during the simulation. In addition to setting the main collision contact between the front of the vehicle and the guardrail, it is also necessary to consider other parts of the vehicle that may come into contact with the guardrail during side slip, rollover, etc. during the collision, such as the frictional contact between the wheels and the bottom of the guardrail, and the collision contact between the side of the vehicle body and the guardrail column. Appropriate contact parameters are set for each contact situation, including the friction coefficient, contact stiffness, contact damping, etc., to ensure the stability and accuracy of the contact calculation.

[0077] Furthermore, the solution of the present application sets reasonable boundary conditions for the guardrail. The columns at the bottom of the guardrail are buried deep underground to a certain depth, and fixed constraints are applied to the bottom nodes of the columns to simulate their fixing method in actual installation. At both ends of the guardrail, appropriate constraint conditions are set according to the actual situation, such as restricting the lateral displacement or applying a certain elastic support to prevent unreasonable overall displacement or vibration of the guardrail during the collision.

[0078] For the vehicle, boundary conditions are set according to its initial motion state. Before the collision, the vehicle is in a free motion state and is not subject to other external constraints except for the action of gravity; at the moment of collision, the initial velocity and angle of the vehicle are set according to the given parameters.

[0079] Preferably, in an embodiment of the present application, the dynamic basic equation is established for simulation by constructing the mass matrix M, stiffness matrix K, damping matrix C, and force vector F:

[0080]

[0081] Among them u are the node acceleration vector, velocity vector, and displacement vector respectively.

[0082] S14. Extract the preset key nodes, and adaptively adjust the simulation calculation according to the deformation change rate of the key nodes to obtain the simulation results.

[0083] Specifically, in order to accurately obtain the drastic changes in collisions during the simulation process, the present application analyzes and measures the collision changes by extracting preset key nodes, and then adaptively adjusts the simulation calculation to improve the accuracy and efficiency of the simulation.

[0084] Preferably, in an embodiment of the present application, during the collision process between the vehicle and the guardrail, first determine the area where the vehicle and the guardrail first come into contact. The nodes in these contact areas play a key role in the transmission of collision forces and the initiation of deformation. Then, extract the nodes on the contact surface between the vehicle and the guardrail as key nodes. For example, in the vehicle finite element model, such as the connection area points between the frame and the body, the connection area points between the suspension system and the frame, the bumper area, etc.; in the guardrail finite element model, the connection area points between the columns and the crossbeams, the connection area points between the anti-collision blocks and the columns and crossbeams, etc.

[0085] Preferably, the adaptive adjustment of the simulation calculation according to the deformation change rate of the key nodes includes:

[0086] S140. Set the initial time step △t 0 。

[0087] S141. Obtain the total load vector of each node at the current time step, update and construct the mass matrix M, stiffness matrix K, and damping matrix C, substitute them into the dynamic equation to obtain the node acceleration vector, and update the node velocity vector and displacement vector:

[0088]

[0089] S142. Calculate the strain tensor of each finite element unit according to the displacements of each node, and determine the deformation magnitude of each finite element unit.

[0090] Preferably, in an embodiment of the present application, for each finite element unit, calculate the strain tensor according to the displacements of its associated nodes. Taking a two-dimensional plane as an example (the principle for three-dimensional problems is similar), assume a quadrilateral (similar to a triangle) unit has four nodes A, B, C, D, and the node displacements are u A 、u B 、u C 、u D 。

[0091] Using geometric relationships and displacement-strain relationships (such as linear geometric equations under small deformation conditions), calculate each component of the strain tensor. For two-dimensional plane stress problems, the strain tensor can be expressed as:

[0092]

[0093] where μ and v are the components of displacement in the x and y directions, and these partial derivatives can be calculated by the finite difference method or a numerical method based on the element shape functions. For three-dimensional tetrahedral elements, the calculation process is similar but involves more nodes and the calculation of shape function derivatives. By taking the partial derivatives of the shape functions at each node and summing them with the nodal displacements, the displacement gradient tensor is obtained, and then the strain tensor is calculated. The calculation process follows the geometric and physical relationships of three-dimensional elasticity theory.

[0094] Furthermore, for the calculated strain tensor, the principal strain eigenvalue λ is calculated by solving the characteristic equation i , and then the equivalent plastic strain is calculated to measure the degree of plastic deformation, which is as follows for two-dimensional and three-dimensional cases respectively:

[0095]

[0096] S143. Calculate the deformation change rate R of the current critical node n .

[0097] Preferably, the calculation of the deformation change rate R of the current critical node n includes:

[0098]

[0099] where m is the number of critical nodes, u j,n , u j,n-1 are the displacement magnitudes of the j-th critical node at the current time step and the previous time step respectively, f j,n , f j,n-1 are the contact force magnitudes of the j-th critical node at the current time step and the previous time step respectively, and γ is the weight parameter.

[0100] S144. If the deformation change rate of the critical node is greater than the first preset value, then adjust the next simulation time step:

[0101]

[0102] where △t n+1 , △t n are the next and current simulation time steps respectively, α 1 is the adjustment coefficient, and α 1 < 1;

[0103] If the deformation change rate of the critical node is less than the second preset value, then adjust the next simulation time step:

[0104]

[0105] where w maxis the highest natural vibration frequency of the system, and α 2 is an adjustment coefficient, and α 2 > 1.

[0106] S145. Continue to the next time step and return to S141 for loop simulation calculation until the simulation time ends.

[0107] In the above solution of this application, by calculating and analyzing the data related to the collision force and node velocity at each time step, using the time-step intelligent control algorithm based on stability analysis, comprehensively considering multiple factors such as the change rate of the collision force, the change rate of the node velocity, and the change rate of energy, the time step is automatically adjusted by setting thresholds. When the collision is severe, the time step is reduced according to the severity to capture details. When the collision is mild, the time step is increased to improve the calculation efficiency, effectively balancing the calculation accuracy and resource consumption, and improving the accuracy and efficiency of the simulation.

[0108] S15. Output the simulation results and correct and optimize the design of the guardrail structure.

[0109] Specifically, after the simulation ends, output the dynamic results such as the motion trajectory, speed change, and acceleration change of the vehicle, and output the deformation conditions of each node unit of the vehicle guardrail, including the numbers, positions of the deformed node units, and measurement parameters of the deformation magnitude (such as strain values, deformation amounts, etc.).

[0110] As Figure 3 (a) shows a comparison diagram of the simulation results and test results of a car colliding with a guardrail in an embodiment of this application. The vehicle driving trajectory, simulation results, and test results are consistent, verifying the accuracy of the large bus simulation model. As Figure 3 (b) shows a comparison deformation diagram of the simulation results and test results of a car and a large bus colliding with a guardrail in an embodiment of this application. The simulation results and test results are consistent, verifying the accuracy of the large bus simulation model. As Figure 3 (c) shows a comparison diagram of the test and computer simulation results of colliding with a reinforced concrete guardrail in an embodiment of this application. It can be seen that the simulation results of the concrete cracks are consistent with the test results, verifying the accuracy and reliability of the reinforced concrete guardrail model.

[0111] Furthermore, post - process and analyze the simulation results, extract the node information of deformation and fracture, including node numbers, positions, degrees of deformation (such as equivalent plastic strain values), etc. And use visualization software to draw the deformation animation of the guardrail and the vehicle during the collision process, highlighting the fractured parts, and intuitively showing the changes in the structure during the collision. At the same time, draw the contour maps of the node deformation degree and fracture situation, representing the deformation or fracture states of different nodes with color distributions, which is convenient for in - depth analysis of the influence law of the collision on the structure and for modifying and optimizing the design of the guardrail. For example: according to the distribution of the vehicle collision force and the deformation of the guardrail in the simulation, reasonably adjust the spacing of the columns. If it is found that the collision force is large and the deformation of the guardrail is concentrated in some areas, the column spacing can be appropriately reduced to increase the overall stiffness and load - bearing capacity of the guardrail; conversely, if in some low - risk areas, the column spacing can be appropriately increased to save material costs and reduce the installation workload. And change the number, height and cross - section shape of the cross - beams according to the simulation results to improve the bending and torsional resistance of the guardrail.

[0112] Furthermore, the method further includes:

[0113] In each time step or iteration step, detect whether each slave point penetrates the master surface. If it penetrates, calculate the interface contact force Fi between the current slave node and the penetrated master surface, use the contact force as the external load vector, and superimpose the internal load vectors corresponding to the node (gravity vector, elastic force vector, plastic force vector, etc.) to obtain the total load vector. If the slave point does not penetrate the master surface, no processing and calculation are performed on this node.

[0114] Preferably, the calculation of the interface contact force F between the current slave node and the penetrated master surface i includes:

[0115] Obtain the penetration depth δ of the current penetrated slave node i ; The penetration depth can be directly obtained from the system. When performing contact detection and calculation by finite element software (such as ABAQUS or ANSYS), the internal position relationship of each slave node relative to the master surface will be tracked.

[0116] The contact force F i satisfies:

[0117]

[0118] where δ i is the penetration depth of the i - th penetrated slave node, k 0 is the initial penalty stiffness parameter, δ is the penetration depth threshold th , and λ and θ are the corresponding adjustment coefficients respectively. That is, if the penetration depth is greater than the preset penetration depth threshold, set the interface contact force F between the current slave node and the penetrated master surface i as:

[0119] F i = k 0 · [1 + λ(δ i - δ th ) θ · δ i ,

[0120] Otherwise, set the interface contact force F between the current slave node and the penetrated master surface i :

[0121] F i = k 0 δ i .

[0122] In the above implementation of the present application, by enabling the penalty stiffness to vary dynamically according to the actual penetration situation during the contact process, the contact behavior can be more reasonably simulated. In the initial stage of contact, when the penetration depth is small, the excessive contact force caused by too high penalty stiffness can be avoided, making the simulation closer to the actual physical situation; when the penetration depth exceeds a certain threshold, the penalty stiffness is adaptively increased to better resist penetration, improving the accuracy of contact force calculation, thereby ensuring the accuracy of contact simulation and improving the reliability of the simulation results.

[0123] Furthermore, the method includes:

[0124] If the deformation change rate of the key node is less than the second preset value and lasts for a preset number of time steps, then adjust and switch to the implicit method to solve the dynamic equation:

[0125] Specifically, in the later stage of the simulation collision or when the movement of the system gradually tends to be stable, switch to using the implicit time integration method (such as the Newmark-β method or the Wilson method) to start solving the dynamic equation. In one implementation, the Newmark-β method is adopted, which specifically includes:

[0126] First, calculate the predicted acceleration, velocity, and displacement according to the formula of the implicit method:

[0127]

[0128] β is an adjustment parameter and β < 1 / 2. Then, iteratively solve to correct the predicted acceleration, velocity, and displacement to satisfy the dynamic equilibrium equation During the iteration process, judge whether the iteration converges according to the convergence criterion (such as the displacement increment or the force imbalance is less than a certain threshold). If it does not converge, continue to adjust the acceleration, velocity, and displacement until the convergence condition is satisfied.

[0129] In the implementation scheme of the present application, during the late stage of collision or when the movement of the system gradually stabilizes, the deformation speed slows down. At this time, the requirement for accuracy mainly focuses on the accurate solution of the static equilibrium state. Therefore, an implicit solution algorithm is adopted, which enables calculations to be carried out with a larger time step, thereby reducing the number of calculation steps, improving the calculation efficiency, and more accurately simulating the dynamic behavior of the entire collision process.

[0130] In one embodiment, as Figure 4 shown, the second aspect of the present application provides a system, and the system includes:

[0131] A model establishment unit, configured to establish finite element models of multiple types of vehicles according to the sizes and characteristics of different types of vehicles; and establish a finite element model of a guardrail according to the current guardrail structure design;

[0132] A parameter setting unit, configured to fit the corresponding material constitutive relationship and input it into the model as material attribute parameters;

[0133] A simulation initial setting unit, configured to set simulation contact and boundary conditions, and establish a dynamic equation for vehicle-guardrail collision simulation;

[0134] A simulation calculation unit, configured to extract preset key nodes, and adaptively adjust the simulation calculation according to the deformation change rate of the key nodes to obtain a simulation result;

[0135] A result output and optimization unit, configured to output the simulation result and correct and optimize the guardrail structure design.

[0136] In one embodiment, the present application also provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the processor is caused to execute the following steps:

[0137] Establish finite element models of multiple types of vehicles according to the sizes and characteristics of different types of vehicles;

[0138] Establish a finite element model of a guardrail according to the current guardrail structure design;

[0139] Fit the corresponding material constitutive relationship and input it into the model as material attribute parameters;

[0140] Set simulation contact and boundary conditions, and establish a dynamic equation for vehicle-guardrail collision simulation;

[0141] Extract preset key nodes, and adaptively adjust the simulation calculation according to the deformation change rate of the key nodes to obtain a simulation result;

[0142] Output the simulation result and correct and optimize the guardrail structure design.

[0143] In one embodiment, as Figure 5 shown, the present application further provides a computer device, including a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor performs the following steps:

[0144] Establish a finite element model of multiple types of vehicles according to the sizes and characteristics of different types of vehicles;

[0145] Establish a finite element model of the guardrail according to the current guardrail structure design;

[0146] Fit to obtain the corresponding material constitutive relationship and input it into the model as material property parameters;

[0147] Set simulation contact and boundary conditions, establish a dynamic equation to conduct a vehicle-guardrail collision simulation;

[0148] Extract preset key nodes, adaptively adjust the simulation calculation according to the deformation change rate of the key nodes, and obtain a simulation result;

[0149] Output the simulation result and correct and optimize the guardrail structure design.

[0150] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database, or other medium used in the various embodiments provided by the present application can include non-volatile and / or volatile memories. Non-volatile memories can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memories can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0151] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0152] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A prefabricated guardrail optimization design simulation method, characterized in that: The method comprises: Establish finite element models of multiple types of vehicles according to their sizes and characteristics; According to the current guardrail structure design, establish the guardrail finite element model; The corresponding material constitutive relation is obtained by fitting and input into the model as material property parameters; Set simulation contact and boundary conditions and establish dynamic equations to simulate the collision between vehicle and guardrail; Extracting preset key nodes, and adaptively adjusting simulation calculations according to the deformation change rates of the key nodes; The simulation results are output, and the guardrail structure design is corrected and optimized.

2. The method according to claim 1, characterized in that The adaptively adjusting the simulation calculation according to the deformation change rate of the key node includes: Get the total load vector of each node at the current time step, substitute it into the dynamic equation to get the node acceleration vector, and update the node velocity vector and displacement vector; Calculate the strain tensor of each finite element unit according to the displacement of each node, and determine the deformation size of each finite element unit; Calculate the deformation change rate R of the current key node n ; If the deformation change rate of the key node is greater than the first preset value, the next simulation time step is adjusted: Among them, △t n+1 , △t n are the simulation time steps of the next and current simulation time steps respectively, α1 is the adjustment coefficient, and α1<1; Continue simulation calculation for the next time step until the simulation time ends.

3. The method according to claim 2, characterized in that The method further comprises: If the deformation change rate of the key node is less than the second preset value, the next simulation time step is adjusted: Among them, w max is the highest natural vibration frequency of the system, α2 is the adjustment coefficient, and α2>1.

4. The method according to claim 3, characterized in that Calculate the deformation change rate R of the current key node n ,include: Where m is the number of key nodes, u j,n 、u j,n-1 are the displacements of the jth key node at the current time step and the previous time step, respectively, and f j,n 、f j,n-1 are the contact forces of the jth key node at the current time step and the previous time step, and γ is the weight parameter.

5. The method according to claim 2, characterized in that: The method further comprises: Check whether each slave point passes through the master surface. If so, calculate the interface contact force F between the current slave node and the penetrated master surface. i , the contact force F i satisfy: Among them, δ i is the penetration depth of the i-th penetration slave node, k0 is the initial penalty stiffness parameter, and is the penetration depth threshold δ th , λ and θ are the corresponding adjustment coefficients respectively; The contact force is used as the external load vector, and the internal load vector corresponding to the node is superimposed to obtain the total load vector.

6. The method according to claim 2, characterized in that The method comprises: If the deformation change rate of the key node is less than a second preset value and lasts for a preset number of time steps, the implicit method is adjusted and switched to solve the dynamic equation.

7. The method according to any one of claims 1 to 6, characterized in that: The method further comprises: Determine whether the structural stress state has reached yield. If not, treat it according to the linear elastic material constitutive model. If the stress exceeds the yield strength, the stress-strain in the structure is calculated according to the plastic or brittle deformation constitutive model.

8. A prefabricated guardrail optimization design simulation system, characterized in that: The system comprises: A model building unit is used to build finite element models of multiple types of vehicles according to the sizes and characteristics of different types of vehicles; and to build a finite element model of the guardrail according to the current guardrail structure design; The parameter setting unit is used to fit the corresponding material constitutive relationship and input it into the model as material property parameters; The simulation initial setting unit is used to set the simulation contact and boundary conditions and establish the dynamic equations for the vehicle-guardrail collision simulation; A simulation calculation unit, used to extract preset key nodes and adaptively adjust the simulation calculation according to the deformation change rate of the key nodes; The result output and optimization unit is used to output the simulation results and correct and optimize the guardrail structure design.

9. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor is caused to perform the steps of the method according to any one of claims 1 to 7.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method according to any one of claims 1 to 7.

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