Longitudinal beam reinforcing rib structure, design method thereof and longitudinal beam structure

Abstract

According to the longitudinal beam reinforcing rib structure, the design method thereof and the longitudinal beam structure, the reinforcing rib design is optimized through the steps of reinforcing rib geometric section design, layout and process collaborative optimization, material and process adaptation, mechanical verification and testing, quality control and the like, the local rigidity of a longitudinal beam is improved, and elastic deformation accumulation in the forming process is actively reduced; and springback after unloading is effectively restrained. And meanwhile, the high rigidity of the reinforcing ribs resists deformation, rebound motion of adjacent areas is restrained, bouncing is made with steel, and the manufacturing precision is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of longitudinal beam stamping technology, specifically to a longitudinal beam reinforcing rib structure and its design method, and a longitudinal beam structure. Background Technology

[0002] In the prior art, in such Figure 1 Springback is a common technical challenge in the stamping process of the longitudinal beam shown. Springback refers to the phenomenon where, after plastic forming (such as bending or stamping), the material recovers its shape when the external force is unloaded, as the internal elastic strain energy is released. In existing technologies, during the bending forming of the longitudinal beam, the elastic deformation in the region near the neutral layer cannot be effectively suppressed, leading to changes in angle or radius after unloading, affecting the dimensional accuracy and assembly performance of the longitudinal beam. Traditional solutions often rely on post-process correction or additional process compensation, but the effects are limited and increase production costs and complexity. Therefore, there is an urgent need for a structural design improvement scheme to improve local bending stiffness from the source and reduce the proportion of elastic deformation in order to effectively control springback. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a longitudinal beam stiffener structure and its design method, as well as a longitudinal beam structure. By optimizing the stiffeners, the local bending stiffness of the longitudinal beam structure is improved, and the springback of the longitudinal beam during the stamping process is reduced.

[0004] To achieve the above-mentioned technical effects, the present invention adopts the following technical solution:

[0005] According to a first aspect of the present invention, a method for designing a longitudinal beam structure is provided, comprising the following steps:

[0006] Step S1. Design the cross-section of the stiffener as T-shaped or L-shaped, and satisfy the following dimensional relationships: stiffener height h = (3~5)t (where t is the thickness of the longitudinal beam plate); stiffener root width w ≥ 2t; stiffener root transition fillet radius r ≥ 3t;

[0007] Step S2. Layout and process co-optimization: Set the longitudinal spacing of the reinforcing ribs on the longitudinal beam according to the formula s≤0.5L, and densify them to s=0.3L in the high springback risk area, where L is the arc length of the bending section of the longitudinal beam; the reinforcing ribs are symmetrically distributed on both sides of the longitudinal beam;

[0008] Step S3. The reinforcing rib is made of duplex steel; a reinforcing rib cavity is set in the mold, and the elastic deformation compensation angle is corrected in reverse based on the CAE springback simulation results;

[0009] Step S4. Mechanical verification: using formula I new =I base +A rib ⋅d2 Calculate the optimized moment of inertia I new , where I base Let A be the foundation moment of inertia without stiffeners. rib Let be the cross-sectional area of ​​the stiffener, and d be the distance from the centroid of the stiffener to the neutral axis, such that the local bending stiffness EI is... new ≥1.2×EI 基础 Among them, EI 基础 This refers to the original bending stiffness of the longitudinal beam matrix without reinforcing ribs, and the effect of reducing springback is verified through CAE simulation.

[0010] Optionally, a quality control step is also included, in which the height tolerance of the reinforcing rib is measured by laser scanning to be ±0.1t and the positional deviation is ≤±0.5mm.

[0011] Optionally, the duplex steel material is HC420 / 780DP.

[0012] Optionally, the target reduction in the rebound amount in step S4 is ≥40%.

[0013] According to a second aspect of the present invention, a longitudinal beam reinforcing rib structure is provided, which is symmetrically arranged on both side walls of the longitudinal beam and designed using the above method.

[0014] According to a third aspect of the present invention, a longitudinal beam structure is provided, wherein the aforementioned longitudinal beam reinforcing rib structure is symmetrically arranged on both side walls.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] This invention improves the local stiffness of the longitudinal beam by optimizing the design of the reinforcing ribs, actively reducing the accumulation of elastic deformation during the forming process and effectively suppressing springback after unloading. The high stiffness of the reinforcing ribs themselves resists deformation and constrains the springback movement of adjacent areas, achieving "rigid control of springback" and significantly improving manufacturing precision (such as springback control of automotive longitudinal beams). Attached Figure Description

[0017] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0018] Figure 1 A schematic diagram of a longitudinal beam structure without reinforcing ribs in the prior art;

[0019] Figure 2 This is a schematic diagram of the longitudinal beam structure with reinforcing ribs as described in the second embodiment. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, all directional indications (such as up, down, left, right, front, back, bottom, etc.) in this application are only used to explain the relative positional relationships and movements between components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indication will also change accordingly. Furthermore, descriptions involving "first," "second," etc., in this application are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0023] Example 1

[0024] This embodiment provides a design method for a longitudinal beam stiffener structure. By designing protruding stiffeners 1 on the sidewall of the longitudinal beam, the local bending stiffness of the longitudinal beam is significantly improved, and elastic recovery deformation after unloading is suppressed. The specific steps include:

[0025] 1. Design of stiffener geometry

[0026] First, this scheme achieves springback control by optimizing the design of the stiffeners on the sidewalls of the longitudinal beams. Specifically, longitudinal protruding stiffeners 1 are designed on the sidewalls of the longitudinal beams, preferably using T-shaped or L-shaped sections, which significantly increase the moment of inertia (I) of the section by utilizing the characteristic that the material distribution is far from the neutral axis. In this process, key parameters need to be calculated accurately: the height (h) is taken as 3 to 5 times the thickness (t) of the plate (i.e., h = (3~5)t) to balance the stiffness requirements and the risk of cracking; the root width (w) needs to meet w≥2t to ensure structural strength and formability; at the same time, the root transition fillet radius (r) is kept at r≥3t to effectively avoid stress concentration.

[0027] 2. Co-optimization of layout and process

[0028] Furthermore, the layout of the reinforcing ribs 1 is dynamically adjusted according to the springback-sensitive areas: the longitudinal spacing (s) of the reinforcing ribs is set according to the formula s≤0.5L (L is the arc length of the bending segment). In particular, the spacing needs to be increased to s = 0.3L in areas with high springback risk. At the same time, in order to eliminate the risk of torsional deformation, reinforcing ribs 1 are symmetrically arranged on both sides of the longitudinal beam.

[0029] 3. Material and process compatibility

[0030] In terms of material selection, dual-phase steel materials such as HC420 / 780DP with high yield strength (σ_s) and plasticity are preferred to achieve a synergy between stiffness and formability. Corresponding process adaptations include: adding reinforcing rib cavities in the mold and correcting the elastic deformation compensation angle in reverse based on CAE springback simulation results; in addition, by optimizing the distribution of blank holder force (increasing the reinforcing rib area by 10%~15%), sufficient material flow is ensured.

[0031] 4. Mechanical verification and testing

[0032] After completing the stiffener design, the effect of improving the moment of inertia is quantified according to the following formula: , among which, I new To optimize the total moment of inertia, I base Based on the fundamental moment of inertia, A rib Let d be the cross-sectional area of ​​the stiffener and d be the distance from the centroid to the neutral axis. The goal is to achieve the desired local bending stiffness of the longitudinal beam structure. EI represents bending stiffness. 基础 The original bending stiffness of the longitudinal beam structure without stiffeners is referred to as 1. AutoForm / Dynaform was used for stamping-springback coupled simulation analysis (CAE) to verify the effect of stiffeners on suppressing the springback angle of the longitudinal beam structure, with a target reduction in springback ≥40%. The ability of a longitudinal beam structure to resist bending deformation is called bending stiffness. Bending stiffness EI is jointly determined by the material's elastic modulus E and the moment of inertia I of the cross-section. I is a geometric parameter that measures the ability of the cross-sectional shape to resist bending deformation; the larger its value, the smaller the bending deformation (curvature) produced under the same bending moment.

[0033] 5. Quality Control Standards

[0034] Finally, strict quality control is implemented in the mass production stage: the longitudinal beams after production are compared with the CAD model by laser scanning, and the springback angle deviation must be ≤0.5°; at the same time, the height tolerance (±0.1t) and position deviation (±0.5mm) of the stiffener 1 must meet the standards to ensure the consistency of stiffness.

[0035] By designing reinforcing ribs 1 on the sidewalls of the longitudinal beams, multiple high-rigidity "anchor points" and "support ribs" are essentially created on the sidewalls of the longitudinal beams, which greatly suppresses the tendency and ability of the material to elastically recover after unloading, thereby effectively reducing the overall rebound amount.

[0036] Example 2

[0037] like Figure 2 As shown, this embodiment provides a longitudinal beam reinforcing rib 1 structure, which is symmetrically arranged on the two side walls of the longitudinal beam base and is designed using the method described in the first embodiment.

[0038] 3rd Embodiment

[0039] like Figure 2 As shown, this embodiment provides a longitudinal beam structure, on which the longitudinal beam reinforcing rib structure described in the second embodiment is symmetrically arranged on both side walls.

[0040] The specific embodiments of the present invention have been described above. Based on the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of the present invention.

Claims

1. A design method for a longitudinal beam stiffener structure, characterized in that, Includes the following steps: Step S1. Design the cross-section of the stiffener as T-shaped or L-shaped, and satisfy the following dimensional relationships: stiffener height h = (3~5)t (where t is the thickness of the longitudinal beam plate); stiffener root width w ≥ 2t; stiffener root transition fillet radius r ≥ 3t; Step S2. Layout and process co-optimization: Set the longitudinal spacing of the reinforcing ribs on the longitudinal beam according to the formula s≤0.5L, and densify them to s=0.3L in the high springback risk area, where L is the arc length of the bending section of the longitudinal beam; the reinforcing ribs are symmetrically distributed on both sides of the longitudinal beam; Step S3. The reinforcing rib is made of duplex steel; a reinforcing rib cavity is set in the mold, and the elastic deformation compensation angle is corrected in reverse based on the CAE springback simulation results; Step S4. Mechanical verification: using formula I new =I base +A rib *d 2 Calculate the optimized moment of inertia I new , where I base Let A be the foundation moment of inertia without stiffeners. rib Let be the cross-sectional area of ​​the stiffener, and d be the distance from the centroid of the stiffener to the neutral axis, such that the local bending stiffness EI is... new ≥1.2×EI 基础 Among them, EI 基础 This refers to the original bending stiffness of the longitudinal beam matrix without reinforcing ribs, and the effect of reducing springback is verified through CAE simulation.

2. The design method for the longitudinal beam stiffener structure as described in claim 1, characterized in that: It also includes quality control steps, such as measuring the height tolerance of the reinforcing ribs with laser scanning to be ±0.1t and the position deviation ≤±0.5mm.

3. The design method for the longitudinal beam stiffener structure as described in claim 1, characterized in that: The duplex steel material is HC420 / 780DP.

4. The design method for the longitudinal beam stiffener structure as described in claim 1, characterized in that: The target for reducing the rebound amount in step S4 is ≥40%.

5. A longitudinal beam reinforcing rib structure, characterized in that, The reinforcing ribs are symmetrically arranged on both side walls of the longitudinal beam and are designed using the method described in any one of claims 1 to 4.

6. A longitudinal beam structure, characterized in that, The longitudinal beam structure is symmetrically provided with longitudinal beam reinforcing ribs as described in claim 5 on both side walls.

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