Reinforced axle housing structure with arbitrary fillet instead of cross-section fillet and design method thereof

Abstract

The application discloses a reinforced axle housing structure with arbitrary curved corners and a design method thereof. The rectangular corner section of the axle housing is connected by four planes through an arbitrary curved corner transition surface. The arbitrary curved corner transition structure is an inner and outer profile corner with a certain thickness formed by an arbitrary curved corner profile. The arbitrary curved corner profile is controlled and realized by a group of optimization equations. The optimization equations include 12 parameters coupling the shape and size of the curved corner for controlling and realizing the changes of the axial and circumferential thickness and the shape of the curved corner. Compared with the prior art, the application can realize the lightweight structure design purpose of the automobile axle with no performance reduction and quality decrease.

Description

Technical Field

[0001] This invention belongs to the field of automotive axle lightweighting, and particularly relates to a reinforced axle shell structure with a cross-sectional fillet that can be modified into an arbitrary curved angle, and its design method. Background Technology

[0002] The driven axle housing mainly supports the sprung mass of the vehicle and bears the transmission of vertical force, longitudinal force, lateral force and braking torque between the frame or monocoque body and the wheels.

[0003] Currently, the bridge shell types available on the market are circular and rounded rectangle, with rounded rectangle being the most common. Drawing rounded corners from a rectangular cross-section helps reduce stress concentration and improve the mechanical properties of the cross-section. However, the control parameter for rounded corners is only the radius. Although designing rounded corners is simple, it lacks flexibility when optimizing.

[0004] Currently, the design of axle housing structures mainly focuses on their geometric dimensions, with very little research on their cross-sectional fillets. Moreover, most research and design work focuses on the fillet radius, without considering the shape of the curved corners. Taking the axle housing of a driven axle as an example, most axle housings used in large trucks are currently rounded rectangular axle housings. The main reason is that rounded rectangular cross-sections have fewer design parameters and are simpler to design. However, with the advancement of optimization technology, multivariate optimization can achieve better design solutions than single-variable optimization.

[0005] Besides the fillet shape of the bridge shell cross-section, the current use of uniform cross-section bridge shells limits optimization to a few sections, resulting in limited design possibilities. Furthermore, optimization of the same cross-section is constrained by the limitations of finite element software. Most optimization parameters currently focus on the bridge shell thickness, specifically fixing the inner cross-section dimensions and optimizing the outer cross-section, or vice versa. Simultaneous optimization of both inner and outer cross-section dimensions is impossible, leading to limited optimization parameters and localized solutions rather than globally optimal ones. Therefore, a better optimal design method is needed, combining advanced design theories and technological conditions to achieve optimal design of lightweight bridge shell dimensions. Summary of the Invention

[0006] The technical problem to be solved by this invention is to propose a reinforced axle shell structure and design method that changes the rounded corners of the cross section to arbitrary curved corners, so as to achieve the goal of lightweight automotive axle structure design without reducing performance or quality.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A reinforced bridge shell structure with a cross-sectional rounded corner modified to an arbitrary curved corner is characterized in that: the connection between adjacent rectangular planes of the bridge shell is an inner and outer contour angle with a certain thickness formed by an arbitrary curved corner profile, and the inner and outer contour angles are both formed by connecting the adjacent rectangular planes through an arbitrary curved corner transition surface.

[0008] In the above technical solution, the arbitrary curved profile is controlled and realized by a set of optimization equations. The optimization equations include 12 parameters that optimize and couple the curved shape and size, with 4 shape parameters and 8 size parameters, which are used to control and realize the changes in the axial and circumferential thickness of the cross section and the changes in the curved shape of the cross section.

[0009] In the above technical solution, the arbitrary curved profile includes one of all transitional cross sections between rectangular angles and rhombuses.

[0010] In the above technical solution, the arbitrary curved profile is one of the transitional cross sections in the process of changing from a rhomboid angle to an elliptical angle or a rounded angle and then to a right angle.

[0011] In the above technical solution, the thickness variation along the perimeter of the rectangular cross-section remains consistent with that at the inner and outer contour corners.

[0012] A method for designing a reinforced bridge shell structure by changing the fillet of the cross-section to an arbitrary curved angle, characterized by the following steps: S1: Take half of the bridge housing as the design object; S2: Optimize the rectangular rounded corner section of the bridge shell, define the control equation for arbitrary curved corner sections, adjust the section size parameters and curved corner shape parameters, control the shape change of the curved corner and the size of the section, and generate the profile of the section with arbitrary curved corner shape; S3: Perform a stress analysis on the original bridge shell, calculate the concentrated forces and moments at each section, and calculate the maximum equivalent stress; S4: Using the original cross-section dimensions and maximum cross-section stress as constraints, optimize the cross-section using different arbitrary curvature angle optimization schemes; S5: The optimization scheme is optimized using an optimization algorithm, and three different curved angle types of cross-sectional shapes are designed for each cross-section; S6: Perform stress analysis on the designed arbitrary curved section, compare the stress cloud diagrams of the section before and after optimization, and select the rectangular rounded section with smaller area and higher stress per unit area as the final rectangular rounded section.

[0013] In the above technical solution, the governing equation for the arbitrary curved section in step S2 is: Inner contour curve equation ; Equation of outer contour curve ; Among them, the outer contour width 2A, height 2B, inner contour width 2a, height 2b, outer curvature angle width A1, height B1, and inner curvature angle width a1, height b1 are eight parameters that control the size of the cross-section; N1, N2, n1, and n2 are curvature angle shape harmonization parameters, and these four parameters control the shape of the curvature angle. The outer contour parameters A, B, A1, B1 and the inner contour parameters a, b, a1, b1 are related through the cross-section thickness h, and the specific relationship is: a = A h, b = B h, a1 = A1 h, b1 = B1 h; The inner and outer curvature angle dimensions further satisfy: a1 = a (A) A1), b1 = b (B) B1).

[0014] In the above technical solution, the range of the curved shape harmonization parameter in step S2 is 0.5~2, and the value step size is 0.1.

[0015] In the above technical solution, step S4 aims to minimize the cross-sectional area. The variable constraints are: ; Mechanical performance constraints ; In the formula: The maximum equivalent stress of an arbitrary curved cross section under the action of a limiting force system. The maximum equivalent stress of the original rounded rectangular cross section under the action of the limit force system; the outer contour width is 2A, the height is 2B, the inner contour width is 2a, the height is 2b, the outer curved corner width is A1, the height is B1, the inner curved corner width is a1, and the height is b1; N1, N2, n1, and n2 are the corner shape harmony parameters. a1=a-(A-A1), b1=b-(B-B1), N1=n1=P1, N2=n2=P2.; a=Ah, b=Bh, a1=A1-h, b1=B1—h.

[0016] In the above technical solution, the optimization schemes for different arbitrary curvature angles in step S4 include: An optimization scheme for fixed-thickness curved corners that does not change the original cross-sectional thickness but only changes the shape of the curved corners: Optimization variables: outer curved corner width A1, height B1, curved corner shape harmonization intermediate parameters P1, P2; Other variable settings: a1=a-(A-A1), b1=b-(B-B1), N1=n1=P1, N2=n2=P2; Invariants: A, B, a, b. The requirement is to optimize the cross-section with equal thickness and to modify the shape of the curved corners to achieve equal thickness optimization. Optimization variables: outer curved corner width A1, height B1, thickness h, and intermediate parameters P1 and P2 for curved corner shape harmonization; other variables are set as follows: a=Ah, b=Bh, a1=A1-h, b1=B1-h, N1=n1=P1, N2=n2=P2; invariants: A, B. The requirement is to optimize the cross-section with varying thickness and to change the shape of the curved corners. The optimization variables are: outer curved corner width A1, height B1, inner curved corner width a1, height b1, and curved corner shape harmonic parameters N1, n1, N2, n2; invariants are: A, B, a, b.

[0017] This invention strengthens the overall strength of the bridge shell by changing the rounded corners of the traditional bridge shell to curved corners.

[0018] In the above technical solution, the inner and outer contour angles of the same rectangular plane connection point within the same bridge shell are consistent. The inner and outer shapes can be the same or different, controlled by the shape parameters in the equation; if the shape parameters are equal, they are the same, and if they are unequal, they are different.

[0019] The traditional rounded rectangular bridge shell structure is transformed into an arbitrary curved rectangular bridge shell structure. The curved corners of the cross-section have dual variability in shape and size, enabling synergistic optimization of the curved corner shape and size. The cross-sectional shape of the bridge shell is an arbitrary curved rectangular section, which can be optimized to produce sharp corners, rounded corners, elliptical corners, and numerous transitional cross-section bevel types, including several novel bevels with superior performance. The size and shape of the bevels in the bridge shell cross-section are controlled by a unified set of equations, each with 12 parameters: 4 shape parameters and 8 size parameters. This is a new method for coupling the optimization of bevel shape and size. Through the optimization of the arbitrary curved corners, the cross-section of the bridge shell can have variable thickness along the circumference and axial direction, thus possessing variable size properties. By designing the original bridge shell by changing the rounded corners to arbitrary curved corners, the goal of lightweighting the bridge shell is achieved. This invention develops many novel curved cross-section bridge shells not found in the market. By changing the rounded corners of the traditional bridge shell to curved corners, the overall strength of the bridge shell is enhanced, resulting in a completely new reinforced bridge shell structure.

[0020] Based on the performance of the original cross section, the cross section fillet is further optimized and designed as an arbitrary curved angle. The inner and outer contour angles are composed of arbitrary curved angles, and the realization of the arbitrary curved angles is controlled by a set of equations.

[0021] The cross-sectional curved angle has both shape and size variability. The shape of the curved angle changes continuously, from a rhomboid angle to an elliptical angle (rounded angle) and then to a right angle, including any shape of angle in between. The size of the curved angle changes by controlling the length changes in two mutually perpendicular directions of the curved angle, which can realize the variable size of the curved angle.

[0022] The reinforced bridge shell structure is designed to reduce the overall mass of the bridge shell by optimizing the cross-sectional area while maintaining the original mechanical properties of the bridge shell.

[0023] Furthermore, the arbitrary curved cross section of the bridge shell is specifically designed with arbitrary curved corners at the four corners of the cross section, improving the traditional rounded rectangular cross section into an arbitrary curved corner type. The design is only applied to the original rounded rectangular cross section of the bridge shell, and other types of cross sections are not improved. After determining that the rounded rectangular cross section should be improved with arbitrary curved corners, the next step is to determine the optimization scheme to optimize the model.

[0024] The cross-sectional curvature has the characteristic of varying thickness along the circumferential and axial directions, which is the result of the combined effect of the inner and outer contour curvatures, and can obtain cross-sectional types with thick corners and thin edges or thin corners and thick edges.

[0025] Furthermore, the optimization scheme specifically includes three sets of optimization schemes: constant thickness of curved corners, uniform thickness of curved corners, and variable thickness of curved corners. The constant thickness optimization scheme is based on the original rounded rectangular cross-section, without changing the thickness of the cross-section, but by changing the shape of the curved corners of the cross-section, thereby reducing the cross-sectional area. The uniform thickness optimization scheme is based on the original rounded rectangular cross-section, but by changing the thickness of the cross-section while maintaining the uniform thickness in the circumference and the shape of the curved corners of the cross-section, thereby reducing the cross-sectional area. The variable thickness optimization scheme is based on the original rounded rectangular cross-section, but by changing the thickness in the circumference of the cross-section and changing the shape of the curved corners of the cross-section, thereby reducing the cross-sectional area. After determining the optimization scheme according to the requirements, the next step is to use the optimal design method to optimize the selected optimization scheme.

[0026] The bridge shell structure takes into account actual processing requirements. The curved corners can be designed in two forms: constant thickness and variable thickness. The constant thickness can be designed according to a specified thickness. The shape, size, and thickness can all be optimized according to the predetermined settings, which makes the design highly flexible. The parameters of the control equation of the curved corner of each section are optimized by a program to make the mechanical properties of each section optimal, thereby making the overall structure optimal.

[0027] Furthermore, the optimal design method involves establishing an optimization model for an arbitrary curved section. The governing equation for the arbitrary curved section has 12 parameters. The required section parameters are determined as design variables based on the optimization scheme. The cross-sectional area is used as the objective function, and the original cross-sectional dimensions and mechanical properties are used as constraints. The differential evolution algorithm is then employed for optimization.

[0028] Based on its structural characteristics, the bridge shell is designed by taking several key rounded rectangular sections and using arbitrary curved angles to optimize the original rounded corners in parallel.

[0029] Furthermore, since the governing equations for arbitrary curved sections couple the shape and size of the curved section, the two attributes of shape and size are optimized in parallel during optimization. The optimized curved section shape is not fixed. In addition to rounded corners, elliptical corners, and other types of transitional section bevels, new curved sections can be constructed.

[0030] Furthermore, because the thickness of the bevel at each cross section varies along the circumferential and axial directions, it has the characteristic of bevel thickness.

[0031] Furthermore, since the optimization model of arbitrary curved section takes the mechanical properties of the original initial section as the minimum constraint, the mechanical properties of the new section obtained must be greater than or equal to those of the original initial section. As for the cross-sectional area as the optimization target, the area of ​​the optimized new cross-section must also be smaller than that of the original section. Therefore, by changing the original angle of the cross-section to an arbitrary curved angle, the overall mass of the original bridge shell can be reduced under the condition that the mechanical properties remain unchanged, thus creating a new type of reinforced bridge shell structure.

[0032] Therefore, this invention provides a reinforced bridge shell structure that changes the rounded corners of the cross-section to arbitrary curved corners. It is formed by lofting modeling of arbitrary curved corner cross-sections of different shapes and sizes. The dimensional parameters of each cross-section are obtained through optimal design methods. The whole structure has the characteristics of variable size and variable shape, so as to achieve the goal of lightweighting with unchanged mechanical properties and reduced weight before and after optimization of the bridge shell.

[0033] The traditional rounded rectangular bridge shell structure is transformed into an arbitrary curved rectangular bridge shell structure. The curved corner of the cross section has dual variability in shape and size, which can achieve synergistic optimization of the curved corner shape and size. The cross section shape of the bridge shell is an arbitrary curved rectangular section, and through optimization, it is possible to obtain sharp corners, rounded corners, elliptical corners and countless transitional cross section bevel types, including many new bevel types with superior performance. The dimensions and shape of the cross-sectional chamfer of the bridge shell are controlled by a unified set of equations, each with 12 parameters, including 4 shape parameters and 8 dimension parameters. This is a new method that couples the optimization of chamfer shape and size. By optimizing the arbitrary curvature of the cross-section, the cross-section of the bridge shell can have variable thickness along the circumferential and axial directions, thus possessing variable size properties. The goal of lightweighting the bridge shell is achieved by designing the original bridge shell by changing the cross-sectional fillet to an arbitrary curvature.

[0034] This invention develops many novel curved-corner bridge shells that do not exist in the market. By changing the rounded corners of traditional bridge shells to curved corners, the overall strength of the bridge shell is enhanced, resulting in a completely new reinforced bridge shell structure.

[0035] The present invention has the following advantages: the cross-sectional curvature shape is arbitrary, allowing for flexible design and enabling the creation of various novel curved cross-sections for bridge shells that are not currently available; compared to existing rounded rectangular bridge shells, the present invention has a smooth cross-sectional transition, preventing stress concentration on the cross-section. Although the rounded rectangular bridge shell has a higher bending resistance coefficient than the arbitrary curved shape, some stress concentration still occurs at the rounded corners, significantly reducing its bending resistance. In contrast, the arbitrary curved cross-section has a uniform curvature transition, preventing stress concentration on the cross-section. Furthermore, the bridge shell cross-section designed with an arbitrary curved profile has a lower mass than the rounded rectangular bridge shell. Attached Figure Description

[0036] Figure 1 The present invention is a reinforced bridge shell structure based on the equation of arbitrary curved section and the contour curve of different curved shape harmonization parameters.

[0037] Figure 2 The reinforced bridge shell structure of this invention is an improvement on the inner and outer cross-sectional contour curves of the original rounded rectangle by using arbitrary curved angles.

[0038] Figure 3 This is a schematic diagram of the positions of the eight key original rectangular cross-sections of the driven axle housing of the present invention. The rectangles are 160mm long and wide, 8mm thick, and have an outer corner radius of 15mm.

[0039] Figure 4 This is a flowchart illustrating the design process of the reinforced bridge shell structure of this invention, which changes the rounded corners of the cross-section to arbitrary curved corners.

[0040] Figure 5 This is a force curve diagram of the eight key cross-sectional locations of the left half of the bridge shell of the present invention.

[0041] Figure 6 This is a schematic diagram comparing the cross-sectional areas and the curved corner shapes of each cross-section before and after optimization using the curved corner thickness scheme of this invention.

[0042] Figure 7 This is a comparison of the cross-sectional areas before and after optimization using the curved angle equal thickness scheme of this invention, and a comparison of the curved angle shapes of each cross-section before and after optimization.

[0043] Figure 8 This is a comparison of the cross-sectional areas before and after optimization using the curved corner thickening scheme of this invention, and a comparison of the curved corner shapes of each cross-section before and after optimization.

[0044] Figure 9 These are stress cloud diagrams of various sections before and after optimization of the eight key sections of this invention. Detailed Implementation

[0045] The following is in conjunction with the appendix Figure 1-9 The present invention provides a detailed description of a reinforced bridge shell structure with a cross-sectional rounded corner that can be modified into an arbitrary curved corner.

[0046] like Figure 1 The figure shows the arbitrary curved profile curve used in the reinforced bridge shell structure of this invention. Different curved angles can be obtained by taking different shape harmonic parameter values. Arbitrary curved angles are used to replace the rounded rectangular cross-sections of bridge shells on the market, such as... Figure 2 As shown, the bridge shell cross-section is symmetrical from top to bottom and left to right. That is to say, the four corners of the bridge shell cross-section are all arbitrary curved corner structures of the same size and shape, while the inner and outer contour surface shapes at the same corner are different.

[0047] The present invention proposes arbitrary curved profile pairs, such as... Figure 3 The eight key sections of the bridge shell shown are optimized. Considering actual processing limitations, improving optimization speed, and ensuring optimal results, the design space of variables is reduced. This invention designs three sets of arbitrary curvature angle optimization schemes.

[0048] Figure 4 This is a flowchart illustrating the design process of the reinforced bridge shell structure of this invention, which changes the cross-sectional rounded corners to arbitrary curved corners. It includes, in sequence, the following steps: The program inputs the initial cross-section of the fillet, selects the first cross-section segment, calculates the cross-sectional properties and performs stress analysis, calculates the original cross-sectional performance, selects the optimization scheme and cross-sectional optimization model, programs to solve for the optimal parameters, stores the solution set X, iterates 8 times, and outputs a new type of cross-section with an arbitrary fillet angle. Details are as follows: Step 1: Since the driven bridge housing is symmetrical, half of the housing is taken as the design object.

[0049] Step 2: Optimize the design of the rounded rectangular section of the bridge shell. Input the initial section with rounded corners, and initialize the first section. Step 3: Perform a stress analysis on the original bridge shell, calculate the moment of each section, and calculate its maximum equivalent stress.

[0050] Figure 5 This is a force curve diagram showing the stress at eight key cross-sectional locations of the left half of the axle housing of this invention. It includes the vertical bending moment generated by 2.5 times the rated load, i.e., the impact load, the lateral bending moment generated by the braking force, and the braking torque.

[0051] Step 4: Optimize the cross section using different arbitrary curvature optimization schemes, using the original cross section dimensions and the maximum cross section stress value as constraints.

[0052] Step 5: Optimize the various arbitrary curvature angle optimization schemes using optimization algorithms. For each cross-section, design three different cross-sectional shapes with varying curvature angles, such as... Figure 6-8 As shown.

[0053] Step 6: Perform stress analysis on the designed arbitrary curved section, and compare the stress cloud diagrams of the section before and after optimization, such as... Figure 9As shown, it can be seen that the stress distribution of a cross section with arbitrary curvature is more uniform than that of a rounded rectangle. Although the maximum stress is the same, the area of ​​the arbitrary curvature cross section is smaller, the stress per unit area is greater, and the material utilization rate is higher.

[0054] As shown in Table 1, the mass of the bridge shell before and after optimization using arbitrary curvature angles can be reduced by up to 4.06% by optimizing the fillet of the original cross section using arbitrary curvature angles.

[0055] Table 1. Bridge housing mass before and after optimization

[0056] The design method of this invention is as follows: 1) Mathematical model of arbitrary curved section Inspired by the hyperellipse equation, the governing equations for arbitrary curved sections were designed as follows.

[0057] Inner contour curve equation ; Equation of outer contour curve ; Among them, the outer contour width 2A, height 2B, inner contour width 2a, height 2b, outer curved angle width A1, height B1, inner curved angle width a1, height b1, these 8 parameters control the size of the cross section; N1, N2, n1, n2 are curved angle shape harmonization parameters, these four parameters control the shape of the curved angle; Based on the above governing equations, the cross-section is designed. In this embodiment of the invention, A1=5, B1=7, and the two shape harmony parameters are taken to have the same value, ranging from 0.5 to 2, with a value step size of 0.1. The arbitrary curved shape contour is drawn as follows. Figure 1 As shown.

[0058] As shown in Figure 1, the curved profile includes all transitional sections between rectangular and rhomboid angles. The larger the shape harmony parameter, the smaller the curvature of the curved angle. When the curvature is as small as a constant value, it approximates a right angle.

[0059] use Figure 1 The arbitrary curved corners replace the four rounded corners of the rounded rectangle, such as... Figure 2 The equation parameters are optimized using an arbitrary curved section optimization model to achieve a reduction in bridge shell mass.

[0060] 2) Optimization Plan Based on actual processing requirements, the cross-sectional curvature angle optimization design is divided into three optimization schemes: fixed thickness reshaping of curvature angle, equal thickness reshaping of curvature angle, and variable thickness reshaping of curvature angle.

[0061] ① Curved angle thickness optimization scheme, such as Figure 6 As shown.

[0062] Applicable conditions: The original cross-sectional thickness must not be changed, only the shape of the curved corner must be changed.

[0063] Optimization variables: outer curvature angle width A1, height B1, curvature angle shape harmonization intermediate parameters P1, P2. The remaining variables are set as follows: a1=a-(A-A1), b1=b-(B-B1), N1=n1=P1, N2=n2=P2. Invariants: A,B,a,b.

[0064] ② Optimization scheme for equal thickness at curved corners, such as Figure 7 As shown.

[0065] Applicable conditions: The cross section is required to be optimized with equal thickness and the shape of the curved corner is changed.

[0066] Optimization variables: outer curvature width A1, height B1, thickness h, curvature shape harmonization intermediate parameters P1, P2. The remaining variables are set as follows: a=Ah, b=Bh, a1=A1-h, b1=B1-h, N1=n1=P1, N2=n2=P2. Invariants: A, B.

[0067] ③ Optimization scheme for thickened curved corners, such as Figure 8 As shown.

[0068] Applicable conditions: The cross section is required to be optimized for variable thickness and the shape of the curved corners is changed.

[0069] Optimization variables: outer curvature angle width A1, height B1, inner curvature angle width a1, height b1, curvature angle shape harmonization parameters N1, n1, N2, n2. Invariants: A,B,a,b.

[0070] 3) Optimization model for arbitrary curved sections The objective function is to minimize the cross-sectional area.

[0071] The optimization variables determined by the optimization scheme are used as design variables; The constraints are as follows: Variable constraints: ; Mechanical performance constraints: ; In the formula: The maximum equivalent stress of an arbitrary curved cross section under the action of a limiting force system. This represents the maximum equivalent stress of the original rounded rectangular cross section under the action of the limit force system.

[0072] 3) Specific operations for optimizing arbitrary curved cross-sections Taking a driven axle with a rated load of 5 tons as an example, the maximum theoretical stress of its axle shell cross-section under extreme working conditions is 300 MPa. The extreme working condition is when the axle shell is subjected to an impact load while a braking force is applied. Under this condition, the torque, vertical and lateral bending moments of the driven axle shell are at their maximum.

[0073] like Figure 5 The moment acting on the left half of the bridge shell is shown. Stress analysis is performed on the original eight cross-sections, using the maximum stress and dimensional conditions of the original cross-sections as constraints. Three optimization schemes are used to optimize the cross-sectional curvature angles. A differential evolution algorithm is used for programming and solving, thereby obtaining the optimal dimensional parameters for each curvature angle. The optimal curvature angle parameters corresponding to the eight cross-sections are plotted as cross-sectional shapes, as shown below. Figure 6-8 The comparison figures show the solutions for constant thickness at curved corners, equal thickness at curved corners, and variable thickness at curved corners, respectively.

[0074] Depend on Figure 6-8 It can be seen that the cross-sectional areas obtained using all three optimization schemes are smaller than the original cross-sectional area. Next, stress analysis is performed on the cross-sectional shapes before and after optimization using arbitrary curvature angles, such as... Figure 6-8 As shown in the cross-sectional area curves before and after optimization, the designed arbitrary curved section has a more uniform stress distribution than the original rectangular section, and the maximum stress is the same, meeting the design requirements. Finally, these arbitrary curved sections are modeled in 3D and replaced with... Figure 5 The eight rounded rectangular cross-sections shown in the figure yielded the optimized mass of the three bridge housings and the corresponding weight reduction, as shown in Table 1.

[0075] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A reinforced bridge shell structure with arbitrary curved angles instead of rounded corners, characterized in that: The connection between adjacent rectangular planes of the bridge shell consists of inner and outer contour angles with a certain thickness, formed by arbitrary curved contours. Both inner and outer contour angles are formed by connecting adjacent rectangular planes through arbitrary curved transition surfaces. These arbitrary curved contours are controlled by a set of optimization equations, which include 12 parameters that couple the shape and size of the curved contours to control the axial and circumferential thickness variations of the cross-section and the shape variations of the curved contours. Wherein: The contour curve of the outer contour satisfies the following system of equations: ； The contour curve of the inner contour satisfies the following system of equations: ； In the formula, 2A and 2B are the width and height of the outer contour, respectively, and 2a and 2b are the width and height of the inner contour, respectively; A1 and B1 are the width and height of the outer curved angle, respectively, and a1 and b1 are the width and height of the inner curved angle, respectively. These 8 parameters are dimensional parameters; N1, N2, n1, and n2 are curved angle shape harmony parameters, constituting 4 shape parameters; the inner and outer contour parameters satisfy the thickness-dimensional coupling relationship of a = Ah, b = Bh, a1 = A1-h, b1 = B1-h, and a1 = a-(A-A1), b1 = b-(B-B1), where h is the cross-sectional thickness.

2. The reinforced bridge shell structure with arbitrary curved angles instead of rounded corners as described in claim 1, characterized in that: The arbitrary curved profile includes one of all transitional cross sections between rectangular angles and rhomboid angles.

3. The reinforced bridge shell structure with arbitrary curved angles instead of rounded corners as described in claim 1, characterized in that: The arbitrary curved profile is one of the transitional cross sections in the process of changing from a rhomboid angle to an elliptical angle or a rounded angle and then to a right angle.

4. The reinforced bridge shell structure with arbitrary curved angles instead of rounded corners according to claim 1, characterized in that: The inner and outer contour angles at the same rectangular plane connection point of the same bridge shell are either identical or different.

5. A design method for a reinforced bridge shell structure that transforms rounded corners into arbitrary curved corners, characterized in that... Includes the following steps: S1: Take half of the bridge shell along the length as the design object, and design the entire bridge shell structure symmetrically from left to right. S2: Take the rectangular rounded corner section of half of the bridge shell for optimization design, define the control equation of arbitrary curved corner section, adjust the section size parameters and curved corner shape parameters, control the shape change of the curved corner and the section size, and generate the cross-sectional profile of arbitrary curved corner shape; the control equation of the arbitrary curved corner section is consistent with the inner and outer contour curve equations defined in claim 1; S3: Perform a stress analysis on the original bridge shell, calculate the concentrated forces and moments at each section, and calculate the maximum equivalent stress; S4: Using the original cross-section dimensions and maximum cross-section stress as constraints, and with the minimum cross-sectional area as the objective function min S, the cross-section is optimized using different arbitrary curvature optimization schemes; S5: The differential evolution algorithm is used to optimize the optimization scheme, and three different curved angle types of cross-sectional shapes are designed for each cross-section; S6: Perform stress analysis on the designed arbitrary curved section, compare the stress cloud diagrams of the section before and after optimization, and select the section shape with smaller area and higher stress per unit area as the final section.

6. The design method for a reinforced bridge shell structure by changing the cross-sectional fillet to an arbitrary curved angle as described in claim 5, characterized in that... In step S2, the range of the curve shape harmonization parameter is 0.5 to 2, and the step size is 0.

1.

7. The design method for a reinforced bridge shell structure by changing the cross-sectional fillet to an arbitrary curved angle as described in claim 5, characterized in that... Step S4 aims to minimize the cross-sectional area (min S), with the following variable constraints: ； Mechanical performance constraints: ； In the formula: The maximum equivalent stress of an arbitrary curved cross section under the action of a limiting force system. The maximum equivalent stress of the original rounded rectangular cross section under the action of the limit force system; the outer contour width is 2A, the height is 2B, the inner contour width is 2a, the height is 2b, the outer curved angle width is A1, the height is B1, the inner curved angle width is a1, and the height is b1; N1, N2, n1, and n2 are the curve shape harmony parameters; a1 = a - (A - A1), b1 = b - (B - B1), N1 = n1 = P1, N2 = n2 = P2; a = Ah, b = Bh, a1 = A1 - h, b1 = B1 - h.

8. The design method for a reinforced bridge shell structure by changing the cross-sectional rounded corner to an arbitrary curved angle as described in claim 5, characterized in that... Step S4 includes different arbitrary curvature angle optimization schemes: An optimization scheme for fixed-thickness curved corners that changes only the shape of the curved corners without altering the original cross-sectional thickness: Optimization variables: outer curved corner width A1, height B1, curved corner shape harmony parameters P1, P2; Other variable settings: a1 = a - (A - A1), b1 = b - (B - B1), N1 = n1 = P1, N2 = n2 = P2; Invariants: A, B, a, b; The requirement is to optimize the cross-section with equal thickness and to modify the shape of the curved corners. The optimization variables are: outer curved corner width A1, height B1, thickness h, and curved corner shape harmonization parameters P1 and P2; other variables are set as follows: a = Ah, b = Bh, a1 = A1-h, b1 = B1-h, N1 = n1 = P1, N2 = n2 = P2; invariants are: A and B. The cross-section is required to be optimized with varying thickness, and the corner shape is changed to achieve a corner-thickness optimization scheme: Optimization variables: outer corner width A1, height B1, inner corner width a1, height b1, corner shape harmony parameters N1, n1, N2, n2; Invariants: A, B, a, b.

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