A database-based cushion block stiffness design method

Abstract

The application provides a database-based cushion block stiffness design method, which establishes a cushion block stiffness curve fitting function and a key parameter value function based on a historical vehicle cushion block stiffness database, calculates different key parameter values A, B, C and D according to the free length and density change of the cushion block, and generates different cushion block stiffness curves. The method can solve the input problem of the cushion block stiffness change scheme used for performance simulation in the early stage, and is used for the simulation analysis and optimization of the ride comfort, handling stability and durability of the vehicle in the early design stage, so that the optimal performance stiffness scheme is obtained through iteration, the number of cushion block sample production and matching test is reduced, and the development cost and period are reduced.

Description

Technical Field

[0001] This invention belongs to the field of automotive suspension performance parameter design technology, specifically relating to a database-based buffer block stiffness design method. Background technology:

[0002] The bump stop is a crucial component of the suspension system, and its mechanical properties affect multiple performance indicators of the vehicle, including ride comfort, handling stability, and durability. Bump stop stiffness is a primary adjustment target during the performance debugging phase of automotive prototype development. It often requires repeated parameter adjustments, the manufacture of numerous prototypes, and their installation in prototype vehicles for evaluation and testing to achieve optimal overall performance. This trial-and-error development model results in high vehicle development costs and long cycles, representing a significant bottleneck in the automotive industry. Furthermore, prototype debugging and evaluation are highly subjective and heavily influenced by the experience of the debugging engineers. Therefore, obtaining a bump stop stiffness solution early in the automotive design process that satisfies electronic prototype performance optimization and multi-objective balance analysis is key to achieving a "design right the first time." Summary of the Invention:

[0003] This invention provides a database-based method for designing buffer block stiffness. By using a buffer block stiffness database, a buffer block stiffness curve fitting function is established. This function yields buffer block stiffness curve schemes for arbitrary free lengths and arbitrary densities (or hardness), which are used to design buffer block stiffness curve schemes. This solves the problem of buffer block stiffness scheme requirements in early-stage simulation analysis of ride comfort, handling stability, and durability, and reduces development costs and time.

[0004] The technical solution of the present invention is as follows:

[0005] A database-based method for designing buffer block stiffness involves establishing a buffer block stiffness curve fitting function F(x) and key parameter value functions A(len,den), B(len,den), C(len,den), and D(len,den) using a buffer block stiffness database. Different key parameter values ​​A, B, C, and D are calculated based on the buffer block's free length and density variations, thereby generating different buffer block stiffness curves. Here, A is the ultimate compression, B is the amplitude coefficient, C is the bending coefficient, D is the amplitude correction coefficient, len is the percentage increase or decrease in the new buffer block's free length, and den is the increase or decrease in the new buffer block's density or hardness level.

[0006] Furthermore, the method includes the following steps:

[0007] 1. Establish a buffer block database based on design parameters such as free length, density (hardness), and stiffness (force-displacement test points) of the buffer block, which will serve as the data basis for establishing the function.

[0008] 2. Based on the buffer block database, analyze the correlation of buffer block design parameters, analyze the characteristics of each stiffness curve, use mathematical statistical analysis methods to find the relationship between buffer block deformation and force, and gradually deduce to establish a buffer block stiffness curve fitting function F(x) with deformation x as the variable, which includes key parameter values ​​A, B, C, and D.

[0009] 3. Based on the buffer block database and the function F(x), calculate the data matrix of A, B, C, and D values ​​under different free lengths and densities. Through statistical analysis of the data, establish functions A(len,den), B(len,den), C(len,den), and D(len,den) with the percentage increase or decrease of the free length of the buffer block (len) and the increase or decrease of the density or hardness level of the buffer block (den) as variables.

[0010] 4. Based on the initial scheme of the buffer block stiffness curve, calculate the initial values ​​of key parameters A0, B0, C0, and D0.

[0011] 5. Based on the new buffer block design, determine the percentage increase or decrease in the free length of the new buffer block (len), and the level of increase or decrease in the density or hardness of the new buffer block (den). Based on the functions A(len,den), B(len,den), C(len,den), D(len,den), A0, B0, C0, D0, and the changes in len and den, calculate the values ​​of A, B, C, and D for different free lengths and densities of the buffer block.

[0012] 6. Based on the function F(x) and the key parameter values ​​A, B, C, and D, generate buffer block stiffness curve schemes with different densities and free lengths, which can be used for early performance simulation optimization and performance balance analysis.

[0013] As can be seen from the above technical solutions, the key to this method is the establishment of a buffer block stiffness curve fitting function F(x) and key parameter value functions A(len,den), B(len,den), C(len,den), and D(len,den) through a buffer block database. Different values ​​of A, B, C, and D are calculated based on the free length and density variations of the buffer block, thereby generating different buffer block stiffness curves. This method, based on a historical vehicle model buffer block stiffness database, forms a set of stiffness curves by fitting the free length and density of the buffer blocks. This solves the problem of the previously scarce input of buffer block stiffness variation schemes suitable for performance simulation. It allows for the application of these inputs to the early stages of vehicle ride comfort, handling stability, and durability simulation analysis and optimization, iteratively obtaining the optimal performance stiffness scheme. This reduces the number of buffer block prototypes to be manufactured and matching tests to be conducted, thereby reducing development costs and time. Attached image description:

[0014] Figure 1 Flowchart of the database-based buffer block stiffness design method described in this invention;

[0015] Figure 2 Schematic diagram of buffer block;

[0016] Figure 3 A comparison of the measured values ​​and the fitted values ​​of the function F(x) of the buffer block stiffness curves;

[0017] Figure 4 Predicted stiffness curves of the new buffer block (with different densities and free lengths). Detailed implementation method:

[0018] To better understand this method, specific examples will be used to illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other.

[0019] like Figure 1 The diagram illustrates a database-based buffer block stiffness design method flow according to an embodiment of this application, including the following steps:

[0020] 1. Establish a buffer block database

[0021] In this step, a buffer block database is established based on design parameters such as the free length, density (hardness), and stiffness (force-displacement test points) of the buffer block. This database serves as the data basis for establishing the buffer block stiffness curve fitting function F(x) and its key parameter value functions A(len,den), B(len,den), C(len,den), and D(len,den).

[0022] 2. Based on the buffer block database, analyze the correlation of buffer block design parameters, analyze the characteristics of each stiffness curve, and use mathematical statistical analysis methods to find the relationship between buffer block deformation and force. Step by step, establish a buffer block stiffness curve fitting function F(x) with deformation x as the variable, which includes key parameter values ​​A, B, C, and D.

[0023]

[0024] In the formula, (1) and (2) are tangent, F is the buffer block force / N, x is the buffer block deformation / mm, A is the ultimate compression, B is the amplitude coefficient, C is the bending coefficient, D is the amplitude correction coefficient, and k is the linear segment stiffness of the buffer block N / mm.

[0025] 3. Based on the buffer block database and function F(x), calculate the data matrix of A, B, C, and D values ​​under different free lengths and densities, and establish key parameter functions A(len,den), B(len,den), C(len,den), and D(len,den) with the percentage increase or decrease of the free length of the buffer block (len) and the increase or decrease of the density or hardness level of the buffer block (den) as variables.

[0026] Specifically, this step involves calculating the key parameter values ​​A, B, C, and D under different free lengths and densities based on the buffer block database and the function F(x), and then analyzing F using mathematical statistics methods. max x max The relationships between F0, x0, len, den, A, B, C, and D are used to determine the key parameter values ​​F0, x0, A, B, C, and D based on F. max x max , len, den, A0, B0, C0, D0 and other functions of changing quantities F0(len,den), x0(len,den), A(len,den), B(len,den), C(len,den), D(len,den);

[0027] x0(len,den)=(1+1.3len)(1-0.05den)x max (3)

[0028] F0(len, den) = F max (4)

[0029] A(len,den)=(1+1.3len)(1-0.05den)A0 (5)

[0030]

[0031] C(len,den)=(1-0.20den)C0 (7)

[0032] D(len,den)=(1-0.05den)D0 (8) where, F max The buffer block force (N) at the limit test point of the buffer block stiffness curve is x. max, where F0 is the buffer block deformation in mm at the limit test point of the new buffer block stiffness curve (as shown in Table 1), x0 is the buffer block force in N at the limit prediction point of the new buffer block stiffness curve, len is the percentage increase or decrease in the free length of the new buffer block, and den is the increase or decrease in the density or hardness level of the new buffer block. In the key parameter values ​​of the finished buffer block stiffness curve, A0 is the ultimate compression, B0 is the amplitude coefficient, C0 is the bending coefficient, and D0 is the amplitude correction coefficient. In the key parameter values ​​of the predicted stiffness curve of the new buffer block, A is the ultimate compression, B is the amplitude coefficient, C is the bending coefficient, and D is the amplitude correction coefficient.

[0033] 4. Based on the initial scheme of the buffer block stiffness curve and the fitting function F(x), calculate the initial values ​​of key parameters A0, B0, C0, and D0. The initial scheme is usually based on the performance requirements of the target vehicle model (such as shock absorber travel, suspension stiffness, etc.), determine the free length of the buffer block, and then select the buffer block stiffness curve with the free length closest to the target from the existing database as the initial scheme.

[0034] For example, in the initial design of the buffer block stiffness curve, the free length of the buffer block (65mm) is as follows: Figure 2 As shown, the density (0.50 g / cc) is used to extract the limit test point (x) for the stiffness of the buffer block. max =43.1, F max =11852.9), as shown in Table 1:

[0035] Table 1. Test points and limit test points for the stiffness curve of the buffer block.

[0036]

[0037] Using least squares regression, a nonlinear least squares method, based on the fitted function F(x), we obtain: A0 = 44.599, B0 = 4093.216, C0 = 5, D0 = 2.051, k = 55.38. A comparison of the measured values ​​and the fitted values ​​of the function F(x) of the buffer block stiffness curve is shown in the figure below. Figure 3 As shown in the figure, it can be clearly seen from the figure that the stiffness curve fitting function F(x) has high accuracy, and the consistency between the measured value and the fitted value is verified, indicating that the stiffness curve fitting function F(x) is scientific.

[0038] 5. Determine the percentage increase or decrease in the free length of the new buffer block (len) and the increase or decrease in the density or hardness of the new buffer block (den) as the new buffer block scheme. Based on the functions A(len,den), B(len,den), C(len,den), and D(len,den) in step (3), A0, B0, C0, and D0 in step (4), as well as the changes in len and den, calculate the values ​​of A, B, C, and D for different free lengths and densities of the buffer block.

[0039] In this step, the percentage increase or decrease in the free length of the new buffer block is len (len = new buffer block free length / initial buffer block free length - 1, len ∈ [-35%, 35%]). The increase or decrease in the density or hardness of the new buffer block is den (den ∈ [-3, 3]). For example: len = -30.8% (free length decreases by 30.8%), -15.4%, 0% (free length remains unchanged), 15.4%, 30.8% (free length increases by 30.8%), den = -2 (density or hardness decreases by 2 levels), -1, 0 (density or hardness remains unchanged), 1, 2 (density or hardness increases by 2 levels).

[0040] Then, based on the functions A(len,den), B(len,den), C(len,den), and D(len,den) from step (3), A0, B0, C0, and D0 from step (4), and the changes in len and den, calculate the A, B, C, and D values ​​of the new buffer block under different free lengths and densities. For example, the following are the A, B, C, and D values ​​under five different free lengths and densities:

[0041] ① When len = -30% and den = -1, the solution is: A = 28.566, B = 4222.706, C = 6, D = 2.154, k = 79.89;

[0042] ② When len = -30% and den = 0, the solution is: A = 27.206, B = 4093.216, C = 5, D = 2.051, k = 90.48;

[0043] ③ When len = -30% and den = 1, the solution is: A = 25.845, B = 3966.822, C = 4, D = 1.949, k = 103.75;

[0044] ④ When len = 0% and den = -1, the solution is: A = 46.829, B = 4222.706, C = 6, D = 2.154, k = 48.88;

[0045] ⑤ When len = 0% and den = 0, the solution is: A = 44.599, B = 4093.216, C = 5, D = 2.051, k = 55.38;

[0046] ⑥ When len = 0% and den = 1, the solution is: A = 42.369, B = 3966.822, C = 4, D = 1.949, k = 63.54.

[0047] 6. Based on the buffer block stiffness curve fitting function F(x) from step (2) and the key parameter values ​​A, B, C, and D of the new buffer block from step (5), generate a set of new buffer block stiffness curve schemes for different densities and different free lengths, such as... Figure 4 As shown, it can be used for early-stage performance simulation optimization and performance balance analysis.

[0048] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0049] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. Furthermore, various different embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed by the present invention.

Claims

1. A database-based buffer block stiffness design method, characterized in that, The method includes the following steps: (1) Establish a buffer block database, which includes design parameters for the free length, density, and stiffness of the buffer blocks; (2) Analyze the correlation of the design parameters of the buffer block, and establish the buffer block stiffness curve fitting function F(x) with the deformation amount x as the variable, which includes the key parameter values ​​A, B, C, and D; the buffer block stiffness curve fitting function F(x) is as follows: In the formula, (1) and (2) are tangent, F is the buffer block force / N, x is the buffer block deformation / mm, and k is the stiffness of the linear segment of the buffer block N / mm; (3) Based on the buffer block database and function F(x), calculate the key parameter values ​​A, B, C, and D data matrices under different free lengths and densities, and establish key parameter functions A(len,den), B(len,den), C(len,den), and D(len,den) with the percentage increase or decrease of the free length of the buffer block len and the increase or decrease of the density or hardness level of the buffer block den as variables. (3) (4) (5) (6) (7) (8) In the formula, F max The buffer block force (N) at the limit test point of the buffer block stiffness curve is x. max , where A0 is the buffer block deformation at the limit test point of the buffer block stiffness curve (mm), F0 is the buffer block force at the limit prediction point of the new buffer block stiffness curve (N), x0 is the buffer block deformation at the limit prediction point of the new buffer block stiffness curve (mm), len is the percentage increase or decrease in the free length of the new buffer block, and den is the increase or decrease in the density or hardness level of the new buffer block; in the key parameter values ​​of the finished buffer block stiffness curve, A0 is the ultimate compression, B0 is the amplitude coefficient, C0 is the bending coefficient, and D0 is the amplitude correction coefficient; in the key parameter values ​​of the predicted stiffness curve of the new buffer block, A is the ultimate compression, B is the amplitude coefficient, C is the bending coefficient, and D is the amplitude correction coefficient. (4) Calculate the initial values ​​of key parameters A0, B0, C0, and D0 based on the initial scheme of the buffer block stiffness curve and the fitting function F(x); (5) Determine the percentage increase or decrease in the free length of the new buffer block (len) and the increase or decrease in the density or hardness of the new buffer block (den) as the new buffer block scheme. Based on the key parameter functions A(len,den), B(len,den), C(len,den), D(len,den), A0, B0, C0, D0, and the changes in len and den, calculate the key parameter values ​​A, B, C, and D of the buffer block under different free lengths and different densities. (6) Based on the buffer block stiffness curve fitting function F(x), the key parameter values ​​are A, B, C, and D. Generate buffer block stiffness curves for different densities and free lengths.

2. The database-based buffer block stiffness design method according to claim 1, characterized in that... The data in the buffer block stiffness database is based on the design parameters of the free length, density, and stiffness of buffer blocks from historical vehicle models.

Images