Simulation method for throttle valve of hydraulic shock absorber

Abstract

The invention discloses a simulation method for a throttle valve of a hydraulic shock absorber, which comprises the following steps for simulating the throttle valve of the hydraulic shock absorber when a simulation actuation test is performed on the hydraulic shock absorber until the hydraulic shock absorber is in a steady-state stage: S1, initializing a fluid part of the throttle valve; s2, solving the fluid part to obtain a first fluid solution; s3, the first fluid solution is loaded to the solid part of the throttling valve, so that the throttling valve displaces, and a first solid solution is obtained; s4, solving the fluid part of the displaced throttle valve to obtain a second fluid solution, and continuously displacing the throttle valve to obtain a second solid solution; s5, an expected threshold value is set, and whether the difference value between the second solid solution and the first solid solution is within the range of the expected threshold value or not is judged; if yes, entering S6; and S6, according to the displacement process of the solid part of the throttling valve, the damping force characteristic of the corresponding hydraulic shock absorber is obtained. According to the method, simulation time consumption can be effectively reduced, and iteration time consumption can be effectively reduced in a mode of performing solid part iteration after fluid part iteration convergence.

Description

Technical Field

[0001] The present invention belongs to the field of automotive hydraulic shock absorbers, and particularly relates to a simulation method for a throttle valve of a hydraulic shock absorber. Background Art

[0002] During the development of automotive hydraulic shock absorbers, a large number of tests are often required for the debugging of the throttle valve inside; currently, the common simulation method for hydraulic shock absorbers is transient simulation. In this simulation process, it is necessary to monitor physical quantities on the flow field (such as pressure difference, maximum flow velocity) or solid domain (such as valve plate displacement, piston rod force) to determine whether the simulation converges as time progresses, resulting in a large amount of work during simulation. And this transient simulation method also has the following problems:

[0003] 1. The process of the throttle valve from the initial state to the stable state requires a large number of time steps and long calculation time, resulting in a contradiction in the selection of grid size.

[0004] 2. It takes a long time to decouple the fluid part and the solid part of the throttle valve.

[0005] 3. A certain amount of calculation time is required for processing in each iteration step.

[0006] 4. It is necessary to verify the independence of the time step for the output results, consuming a large amount of calculation time and workload.

[0007] In summary, there is an urgent need for a method for simulating the damping force of a throttle valve of a hydraulic shock absorber to solve the problems of large workload and long time consumption during transient simulation. Summary of the Invention

[0008] The purpose of the present invention is to provide a simulation method for a throttle valve of a hydraulic shock absorber, which performs fluid-structure coupling simulation on the throttle valve of the hydraulic shock absorber in the steady state stage to obtain the damping force characteristics of the throttle valve of the hydraulic shock absorber at different actuation speeds. Compared with the existing transient simulation method, the steady state simulation method has a greater improvement in calculation speed and reliability.

[0009] To achieve the above invention purpose, the technical solution adopted by the present invention is as follows:

[0010] A simulation method for a throttle valve of a hydraulic shock absorber, when performing a simulation actuation test on the hydraulic shock absorber until it reaches the steady state stage, includes the following steps for simulating the throttle valve of the hydraulic shock absorber:

[0011] Step S1. Initialize the fluid part of the throttle valve according to the actuation speed of the hydraulic shock absorber during the actuation test;

[0012] Step S2. Perform iterative solution on the fluid part in the initial state to obtain the first fluid solution;

[0013] Step S3. Load the first fluid solution to the solid part of the throttle valve to cause displacement of the throttle valve, and iteratively solve to obtain the first solid solution;

[0014] Step S4. Iteratively solve the fluid part of the displaced throttle valve to obtain the second fluid solution, and load the second fluid solution to the solid part of the throttle valve to cause continuous displacement of the throttle valve, and iteratively solve to obtain the second solid solution;

[0015] Step S5. Set the desired threshold, and determine whether the difference between the second solid solution and the first solid solution is within the range of the desired threshold; if so, proceed to Step S6; if not, return to Step S4 to obtain the third solid solution, the fourth fixed solution... the Nth solid solution until the difference between the Nth fixed solution and the (N - 1)th solid solution is within the range of the desired threshold and then proceed to Step S6;

[0016] Step S6. Obtain the damping force characteristic of the corresponding hydraulic shock absorber according to the displacement process of the solid part of the throttle valve.

[0017] A simulation method for a throttle valve of a hydraulic shock absorber according to the present invention solves the fluid part and the solid part of the throttle valve in the steady state stage respectively, and the load of the solid part each time is determined according to the iterative calculation result of the fluid part until the displacement of the solid part converges within the range of the desired threshold and then outputs the result, and obtains the corresponding damping force characteristic of the hydraulic shock absorber according to the change process of the displacement. This steady-state-based simulation method does not need to consider the selection of the time step and does not need to perform the independence verification of the time step, can effectively reduce the simulation time, and the method of performing the solid part iteration after the fluid part iteration converges can effectively reduce the iteration time.

[0018] Preferably, the step S1 includes: establishing a flow field domain and a solid domain, where the fluid part of the throttle valve is located in the flow field domain, the solid part of the throttle valve is located in the solid domain, and an interface is set between the flow field domain and the solid domain, and a flow field solver for solving the fluid part is set in the flow field domain.

[0019] Preferably, in the step S2 and the step S4, the fluid part of the throttle valve is iteratively solved to obtain the pressure received by the fluid part, the flow field velocity corresponding to the received pressure, and the shear force.

[0020] Preferably, the step S2 includes: solving the fluid part of the throttle valve in the flow field domain through a flow field solver, and obtaining the pressure received by the fluid part, the flow field velocity corresponding to the received pressure, and the shear force through n iterative calculations, where 20 ≤ n ≤ 40.

[0021] Preferably, the step S3 includes: loading the pressure and the corresponding shear force received by the fluid part to the solid domain through the interface, applying a load to the solid part of the throttle valve through the pressure and the shear force to cause displacement, and obtaining the displacement of the solid part after m-step iterative calculations, where 3 ≤ m ≤ 5.

[0022] Preferably, the step S4 includes: after each displacement of the solid part is completed, continuing to calculate the pressure and the corresponding shear force received by the fluid part and then applying them to the solid part to cause displacement again, and obtaining the corresponding displacement after m-step iterative calculations.

[0023] Preferably, the step S4 includes: establishing a grid and generating a corresponding flow field change trend diagram of the throttle valve according to the displacement of the solid part each time.

[0024] Preferably, the step S5 includes: setting an expected threshold for the difference. If the difference between the displacement after the solid part is displaced N times and the displacement after the solid part is displaced N - 1 times is within the range of the expected threshold, then proceed to step S6.

[0025] Preferably, the step S5 further includes: setting the expected threshold for the difference to [0, ε). After the solid part is displaced N times, obtaining the displacement S(N) of the Nth displacement and the displacement S(N - 1) of the (N - 1)th displacement, calculating the difference Res = S(N) - S(N - 1). If 0 ≤ Res < ε, then proceed to step S6; where N ≥ 2.

[0026] Preferably, the step S6 includes: obtaining the damping force characteristic corresponding to the hydraulic shock absorber at the actuation speed of this simulation actuation test according to the flow field change trend diagram of the throttle valve.

[0027] Beneficial effects:

[0028] A simulation method for a throttle valve of a hydraulic shock absorber according to the present invention solves the fluid part and the solid part of the throttle valve in a steady state respectively, and the load of the solid part each time is determined according to the iterative calculation result of the fluid part until the displacement of the solid part converges within the range of the expected threshold and then outputs the result, and obtains the damping force characteristic corresponding to the hydraulic shock absorber according to the change process of the displacement. This steady-state-based simulation method does not need to consider the selection of the time step and does not need to verify the independence of the time step, can effectively reduce the simulation time, and the method of performing solid part iteration after the fluid part converges can effectively reduce the iterative time. Description of the drawings

[0029] Figure 1 Shown is the schematic diagram of the transient simulation used in the background technology;

[0030] Figure 2The figure shows a flowchart of a simulation method for a throttle valve of a hydraulic shock absorber according to an embodiment;

[0031] Figure 3 The figure shows a schematic diagram of the principle of a simulation method for a throttle valve of a hydraulic shock absorber according to an embodiment;

[0032] Figure 4 The figure shows a schematic diagram of the throttle valve flow field mesh built during the simulation actuation test of the hydraulic shock absorber according to an embodiment;

[0033] Figure 5 The figure shows a damping force characteristic diagram obtained when the simulation method for a throttle valve of a hydraulic shock absorber according to an embodiment simulates a twin-tube hydraulic shock absorber. Detailed implementation manners

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will describe the specific implementation manners of the present invention with reference to the accompanying drawings. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings, and other implementation manners can also be obtained.

[0035] The following will introduce the technical solutions of the present invention in detail with specific embodiments.

[0036] Embodiment 1

[0037] As Figure 1 The figure shows a schematic diagram of the principle of the transient simulation used in the background technology. During this simulation process, the fluid-solid part of the throttle valve will perform internal iterations at each time step. Only when the iteration converges or reaches the step upper limit will it enter the next time step. At each time step, it is necessary to monitor physical quantities on the flow field (such as pressure difference, maximum flow velocity) or the solid domain (such as valve plate displacement, piston rod force) to determine whether the simulation tends to converge as time progresses.

[0038] As Figures 2 - 3 The figure shows that a simulation method for a throttle valve of a hydraulic shock absorber according to this embodiment, when performing a simulation actuation test on the hydraulic shock absorber until it reaches the steady state stage, includes the following steps for simulating the throttle valve of the hydraulic shock absorber:

[0039] Step S1. Initialize the fluid part of the throttle valve according to the actuation speed of the hydraulic shock absorber during the actuation test;

[0040] Step S2. Perform iterative solution on the fluid part in the initial state to obtain the first fluid solution;

[0041] Step S3. Load the first fluid solution onto the solid part of the throttle valve to cause the throttle valve to displace, and perform iterative solution to obtain the first solid solution;

[0042] Step S4. Iteratively solve the fluid part of the throttle valve after displacement to obtain the second fluid solution, and load the second fluid solution onto the solid part of the throttle valve to cause the throttle valve to continue to displace, and iteratively solve to obtain the second solid solution;

[0043] Step S5. Set an expected threshold, and determine whether the difference between the second solid solution and the first solid solution is within the range of the expected threshold; if so, enter Step S6; otherwise, return to Step S4 to obtain the third solid solution, the fourth fixed solution... the Nth solid solution until the difference between the Nth fixed solution and the (N - 1)th solid solution is within the range of the expected threshold and then enter Step S6;

[0044] Step S6. Obtain the damping force characteristic of the corresponding hydraulic shock absorber according to the displacement process of the solid part of the throttle valve.

[0045] A simulation method for a throttle valve of a hydraulic shock absorber in this embodiment solves the fluid part and the solid part of the throttle valve in the steady state stage respectively, and the load of the solid part each time is determined according to the iterative calculation result of the fluid part until the displacement of the solid part converges within the range of the expected threshold and then the result is output, and the corresponding damping force characteristic of the hydraulic shock absorber is obtained according to the change process of the displacement. This steady-state-based simulation method does not need to consider the selection of the time step and does not need to perform the independence verification of the time step, can effectively reduce the simulation time, and the way of performing the solid part iteration after the fluid part iteration converges can effectively reduce the iteration time.

[0046] Preferably, the step S1 includes: establishing a flow field domain and a solid domain, where the fluid part of the throttle valve is located in the flow field domain, the solid part of the throttle valve is located in the solid domain, an interface is set between the flow field domain and the solid domain, and a flow field solver for solving the fluid part is set in the flow field domain.

[0047] Specifically, the step S1 further includes initializing the flow field domain according to the actuation speed of the hydraulic shock absorber during the actuation test.

[0048] Preferably, in the step S2 and the step S4, the fluid part of the throttle valve is iteratively solved to obtain the pressure received by the fluid part, the flow field velocity corresponding to the received pressure, and the shear force.

[0049] Preferably, the step S2 includes: solving the fluid part of the throttle valve through the flow field solver in the flow field domain, and obtaining the pressure received by the fluid part, the flow field velocity corresponding to the received pressure, and the shear force through n iterative calculations, where 20 ≤ n ≤ 40.

[0050] Preferably, the step S3 includes: loading the pressure and corresponding shear force received by the fluid part to the solid domain through the interface, applying loads to the solid part of the throttle valve through the pressure and shear force to cause displacement, and obtaining the displacement of the solid part through m-step iterative calculation, where 3 ≤ m ≤ 5.

[0051] Preferably, the step S4 includes: after each displacement of the solid part is completed, continue to calculate the pressure and corresponding shear force received by the fluid part and then apply them to the solid part to cause displacement again, and obtain the corresponding displacement through m-step iterative calculation.

[0052] Preferably, the step S4 includes: establishing a grid, and generating a corresponding flow field change trend diagram of the throttle valve according to the displacement of the solid part each time.

[0053] Preferably, the step S5 includes: setting an expected threshold for the difference. If the difference between the displacement after the solid part is displaced N times and the displacement after the solid part is displaced N - 1 times is within the range of the expected threshold, then enter step S6.

[0054] Preferably, the step S5 further includes: setting the expected threshold for the difference as [0, ε). When the solid part is displaced N times, obtain the displacement S(N) of the Nth displacement and the displacement S(N - 1) of the (N - 1)th displacement, calculate the difference Res = S(N) - S(N - 1). If 0 ≤ Res < ε, then enter step S6; where N ≥ 2.

[0055] Preferably, the step S6 includes: obtaining the damping force characteristics corresponding to the hydraulic shock absorber at the actuation speed of this simulation actuation test according to the flow field change trend diagram of the throttle valve.

[0056] Specifically, as Figure 4 shown is a schematic diagram of the throttle valve flow field grid established during the simulation actuation test of the hydraulic shock absorber. In this grid diagram, the grid cell size in the width direction should be small enough to resolve the flow at a small opening of the valve plate. To ensure that the aspect ratio of the grid cells is not too large, the grid in the mainstream direction should also be small enough to ensure simulation convergence.

[0057] Furthermore, whether it is transient simulation or steady-state simulation, it is necessary to consider that the Courant number CFL = vdt / dx cannot be too large, that is, the time step needs to be small enough. This means that when using transient simulation, the number of time steps that need to be calculated from the initial state to stability is large, and the calculation time is long; that is, there is a contradiction in the selection of grid size and time step when using transient simulation. If the steady-state simulation of this embodiment is used, after establishing the throttle valve flow field grid, generate a flow field change trend diagram of the throttle valve according to the displacement of the solid part each time (as Figure 4When the aspect ratio of the grid cell is not too large when the arrow (in the figure) is present, and the grid in the mainstream direction is small enough to ensure the convergence of the simulation. Among them, the flow field change trend diagram of the throttle valve can reflect the change trend of the corresponding flow field of the valve plate of the throttle valve.

[0058] Furthermore, from Figure 1 it can be seen that the solution of the fluid domain and the solid domain using transient simulation is decoupled within each cycle. The number of iteration steps required for the convergence of the solid iteration is much less than that of the flow field solution. Therefore, when using the steady-state simulation of this embodiment, the solid iteration is carried out after the flow field iteration converges, which can effectively reduce the iteration time; if transient simulation is used, the change of the fluid-structure interface in each iteration step will cause grid deformation, resulting in a certain amount of computing time required for processing; and theoretically, transient simulation requires the verification of the independence of the time step, consuming a large amount of computing time and workload.

[0059] Furthermore, the steady-state simulation of this embodiment is based on a steady-state fluid-structure coupling simulation method to simulate the damping force characteristics of the throttle valve or other valve systems of the hydraulic shock absorber at different actuation speeds, improving the calculation speed and reliability of the existing simulation methods.

[0060] Specifically, when using the steady-state simulation of this embodiment, the damping force corresponding to the shock absorber at different actuation speeds can be calculated according to the existing valve system structure, the material characteristics of the valve plate, and the physical properties of the damping oil, providing a simulation basis for the valve system design and reducing the test cost and cycle.

[0061] Specifically, when using the steady-state simulation of this embodiment for the actuation test of the hydraulic shock absorber, only the damping force corresponding to the piston rod moving stably at a certain speed needs to be concerned, and the damping force value during the change of its actuation speed does not need to be concerned; from the perspective of simulation, when the fluid part of the throttle valve is in a stable flow in the flow field, the solid structure (i.e., the valve plate) is in a force balance state, so the steady-state simulation can be used for solution.

[0062] Specifically, when using the steady-state simulation of this embodiment, there is no need to consider the selection of the time step, no need to verify the independence of the time step, and the local refinement of the grid has a smaller impact on the simulation time.

[0063] Specifically, when using the steady-state simulation of this embodiment, the solution of the fluid domain and the solid domain is decoupled within each cycle; generally, the number of iteration steps required for the convergence of the solid iteration is much less than that of the flow field solution. Therefore, the solid iteration is carried out after the flow field iteration converges, which can effectively reduce the iteration time.

[0064] Specifically, the steady-state simulation of this embodiment is only applicable to the simulation of the damping force value in the steady state stage of the actuation test of the hydraulic shock absorber, and is not applicable to the evaluation of the damping force in the transition stage.

[0065] Specifically, when using the steady-state simulation of this embodiment, the mesh deformation is only performed at the end of each iteration cycle, which can effectively reduce the calculation caused by mesh deformation and improve the calculation efficiency.

[0066] Specifically, using the steady-state simulation of this embodiment to simulate the working process of the throttle valve system of an automotive hydraulic shock absorber can evaluate the damping force corresponding to the shock absorber at different actuation speeds, provide a simulation basis for the design and debugging of the throttle valve system, and reduce the test cost and cycle.

[0067] Specifically, compared with the transient simulation commonly used in the background technology, the simulation method of this embodiment can reduce the calculation time, reduce the workload of verifying the irrelevance of the simulation results, and improve the reliability of the simulation.

[0068] Embodiment 2

[0069] This embodiment uses the simulation method of a throttle valve of a hydraulic shock absorber in Embodiment 1 to simulate the damping force of a twin-tube hydraulic shock absorber at an actuation speed of 0.131 m / s, and uses the transient simulation in the background technology for comparison.

[0070] Figure 5 The figure shows a comparison chart of the damping force characteristics obtained by using the transient simulation of the background technology and the steady-state simulation of this embodiment. It can be seen from this figure that the damping force on the piston rod of the twin-tube hydraulic shock absorber has converged when both simulation methods have iterated to 500 steps. However, the convergence speed of the steady-state simulation is faster than that of the transient simulation; and when iterating 500 steps, the time consumed by the steady-state simulation method of this embodiment is reduced by 40% compared with the transient simulation of the background technology.

[0071] The above has elaborated in detail on the embodiments of a simulation method for a throttle valve of a hydraulic shock absorber provided by the present invention. Specific examples are used herein to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the core idea of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A simulation method for a hydraulic shock absorber throttle valve, characterized in that: When the hydraulic shock absorber is subjected to a simulated actuation test until it is in a steady state stage, the following steps are included for simulating the throttle valve of the hydraulic shock absorber: Step S1. Initializing the fluid part of the throttle valve according to the actuation speed of the hydraulic shock absorber during the actuation test; Step S2. Iteratively solve the fluid part of the initial state to obtain a first fluid solution; Step S3. Loading the first fluid solution to the solid part of the throttle valve to displace the throttle valve, and iteratively solving to obtain a first solid solution; Step S4. Iteratively solve the fluid part of the displaced throttle valve to obtain a second fluid solution, and load the second fluid solution to the solid part of the throttle valve to make the throttle valve continue to displace, and iteratively solve to obtain a second solid solution; Step S5. Set the expected threshold value, and determine whether the difference between the second solid solution and the first solid solution is within the range of the expected threshold value; if so, proceed to step S6; if not, return to step S4 to obtain the third solid solution, the fourth solid solution, ... the Nth solid solution, until the difference between the Nth solid solution and the N-1th solid solution is within the range of the expected threshold value and then proceed to step S6; Step S6. Obtain the damping force characteristics of the corresponding hydraulic shock absorber according to the displacement process of the solid part of the throttle valve.

2. The simulation method of the hydraulic shock absorber throttle valve according to claim 1, characterized in that: The step S1 includes: establishing a flow field domain and a solid domain, wherein the fluid part of the throttle valve is located in the flow field domain, the solid part of the throttle valve is located in the solid domain, an interface is set between the flow field domain and the solid domain, and a flow field solver for solving the fluid part is set in the flow field domain.

3. The simulation method of the hydraulic shock absorber throttle valve according to claim 2, characterized in that: In the steps S2 and S4, the fluid part of the throttle valve is iteratively solved to obtain the pressure of the fluid part, the flow field velocity and the shear force corresponding to the pressure.

4. The method for simulating a throttle valve of a hydraulic shock absorber according to claim 3, characterized in that: The step S2 includes: solving the fluid part of the throttle valve by a flow field solver in the flow field domain, and calculating the pressure of the fluid part, the flow field velocity and the shear force corresponding to the pressure through n iterations, wherein 20≤n≤40.

5. The simulation method of the hydraulic shock absorber throttle valve according to claim 3 or 4, characterized in that: The step S3 comprises: loading the pressure and corresponding shear force of the fluid part to the solid domain through the interface, applying a load to the solid part of the throttle valve through the pressure and shear force to cause it to displace, and obtaining the displacement of the solid part through m-step iterative calculation, where 3≤m≤5.

6. The simulation method of the hydraulic shock absorber throttle valve according to claim 5, characterized in that: The step S4 comprises: after each displacement of the solid part is completed, the pressure and the corresponding shear force of the fluid part are calculated, and then they are applied to the solid part to make it displace again, and the corresponding displacement amount is obtained through m-step iterative calculation.

7. The method for simulating a throttle valve of a hydraulic shock absorber according to claim 6, characterized in that: The step S4 includes: establishing a grid, and generating a flow field change trend diagram of the corresponding throttle valve according to the displacement of the solid part each time.

8. The method for simulating a throttle valve of a hydraulic shock absorber according to claim 6, characterized in that: The step S5 includes: setting an expected threshold value of the difference, and if the difference between the displacement amount of the solid part after N times of displacement and the displacement amount after N-1 times of displacement is within the range of the expected threshold value, entering step S6.

9. The simulation method of the hydraulic shock absorber throttle valve according to claim 8, characterized in that: The step S5 also includes: setting the expected threshold of the difference to [0, ε), when the solid part is displaced N times, obtaining the displacement S(N) of the Nth displacement and the displacement S(N-1) of the N-1th displacement, calculating the difference Res=S(N)-S(N-1), if 0≤Res<ε, entering step S6; wherein N≥2.

10. The simulation method of a hydraulic shock absorber throttle valve according to claim 7, characterized in that: The step S6 includes: obtaining the damping force characteristics of the hydraulic shock absorber corresponding to the actuation speed of the simulation actuation test according to the flow field change trend diagram of the throttle valve.

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