A full roof pressure-resistant safety vehicle body structure design method and vehicle body structure

Abstract

The application discloses a whole roof pressure-resistant safety protection vehicle body structure design method and a vehicle body structure. The vehicle body structure comprises a plurality of closed ring body structures. The design method comprises establishing a typical vehicle body rolling condition, setting a load boundary condition of the typical vehicle body rolling condition, and determining a target pressure-bearing value of a key stress area of the vehicle body. Based on the target pressure-bearing value of the key stress area of the vehicle body, a main force transmission path of the typical vehicle body rolling condition is determined through topological optimization, and a closed ring body structure of the vehicle body is constructed. Based on the closed ring body structure of the vehicle body, a key joint area of the vehicle body and a key structure section of the vehicle body are identified and optimized. Based on a forming process and stress distribution, materials of the key joint area of the vehicle body and the key structure section of the vehicle body are selected. Whether the whole vehicle body structure with the optimized and selected key joint area of the vehicle body, the key structure section of the vehicle body and the closed ring body structure of the vehicle body meets safety protection and weight balance requirements of the typical vehicle body rolling condition is verified.

Description

Technical Field

[0001] This invention relates to the field of vehicle body structure design technology, specifically to a design method and structure for a full-roof pressure-resistant safety protection vehicle body structure. Background Technology

[0002] When off-road vehicles are in motion, they often encounter complex road conditions such as rugged mountain roads and soft surfaces, which can easily lead to extreme accidents such as rollovers and overturns, causing severe impacts on the top of the passenger compartment.

[0003] Traditional automotive body structure designs primarily focus on frontal or side impact protection, lacking a systematic protection solution against roof crushing forces. When a vehicle rolls over in different postures, critical load-bearing areas such as the roof, A-pillar, B-pillar, C-pillar, and D-pillar experience uneven stress, making them prone to localized structural deformation or even collapse, seriously threatening the lives of occupants. Existing technologies sometimes reinforce only individual parts of the body without establishing a systematic force transmission path to resist roof crushing under all conditions, resulting in insufficient overall body rigidity and difficulty in coping with diverse rollover scenarios. Furthermore, traditional designs often struggle to balance body rigidity and lightweight requirements. Either they increase material usage for safety, leading to excessive body weight and affecting driving performance; or they weaken structural strength to control weight, reducing protection under extreme conditions and failing to meet the core demands of off-road vehicles for high safety and high reliability.

[0004] Therefore, there is an urgent need to design a vehicle body structure design method and structure that can comprehensively consider the crush safety performance of the vehicle roof, while taking into account the requirements for lightweight body and body rigidity. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide a design method and body structure for a full-roof crush-resistant safety protection body structure that can comprehensively consider the crush safety performance of the vehicle roof, while taking into account the requirements of lightweight body and body rigidity.

[0006] To achieve this objective, the present invention provides a full-roof anti-compression safety protection body structure design method, comprising: establishing a typical body rollover condition, setting the load boundary conditions for the typical body rollover condition, and determining the target bearing pressure value of the key stress areas of the body; based on the target bearing pressure value of the key stress areas, determining the main force transmission path of the typical body rollover condition through topology optimization, and constructing a closed-loop structure of the body; based on the closed-loop structure of the body, identifying and optimizing the key joint areas and key structural sections of the body; selecting the molding materials for the key joint areas and key structural sections of the body based on the molding process and stress distribution; and constructing and verifying whether the optimized and selected key joint areas and key structural sections of the body, as well as the closed-loop structure of the body, meet the safety protection and weight balance requirements of the typical body rollover condition.

[0007] Furthermore, the typical vehicle rollover conditions include: rollover conditions where the front crossbeam of the roof is the primary stress area of ​​the vehicle top; rollover conditions where the upper part of the A-pillar is the primary stress area of ​​the vehicle top; rollover conditions where the center of the top of the side panel is the primary stress area of ​​the vehicle top; rollover conditions where the upper end of the C-pillar or the upper end of the D-pillar is the primary stress area of ​​the vehicle top; and rollover conditions where the rear crossbeam of the roof is the primary stress area of ​​the vehicle top.

[0008] Furthermore, the closed-loop structure of the vehicle body includes: constructing multiple annular force transmission paths formed by the front bulkhead, body pillars, roof beam, sill beam, floor beam, front anti-collision beam, water tank upper crossbeam, front pillar, front longitudinal beam, wheel arch beam, wheel arch pillar, and front compartment upper longitudinal beam.

[0009] Furthermore, the method for identifying and optimizing the critical joint area of ​​the vehicle body includes: increasing the load-bearing area of ​​the joint area of ​​the multiple annular force transmission paths, setting through support members and / or reinforcing partitions inside the joint area of ​​the vehicle body, extending the overlap length between the joint area of ​​the vehicle body and adjacent components, and smoothing the transition rounded corners of the joint area of ​​the vehicle body.

[0010] Furthermore, the method for identifying and optimizing the structure of key structural sections of the vehicle body includes: performing mechanical simulation analysis on the entire vehicle body structure based on the load spectrum of the typical vehicle body rollover condition, simulating the force flow transmission path, and identifying key structural sections of the vehicle body.

[0011] Furthermore, the method for identifying and optimizing the cross-section of the key body structure also includes: conducting sensitivity analysis on the factors affecting the load-bearing capacity of the key body structure, screening out the influencing factors related to the load-bearing capacity of the key body structure as key factors affecting the load-bearing capacity of the key body structure, and optimizing the key factors.

[0012] Furthermore, the method of conducting sensitivity analysis on factors affecting the load-bearing capacity of the key body structure, screening out influencing factors related to the load-bearing capacity of the key body structure as key factors affecting the load-bearing capacity of the key body structure, and optimizing the key factors includes: based on the calculation formula of the maximum crushing force of the cross-section of the key body structure, screening out influencing factors related to the maximum crushing force of the cross-section of the key body structure as key factors affecting the load-bearing capacity of the key body structure, and optimizing the key factors; the expression of the calculation formula of the maximum crushing force of the cross-section of the key body structure is: ,in, This represents the maximum crushing force at the critical structural section of the vehicle body. Let A be the critical compressive stress of a single critical structural section of the vehicle body, and let A be the cross-sectional area of ​​that section. The formula for calculating the critical compressive stress of a single critical structural section of the vehicle body is as follows: Where E is the elastic modulus of the material of the critical structural section of the vehicle body, ν is the Poisson's coefficient of the material of the critical structural section of the vehicle body, t is the material thickness of the material of the critical structural section of the vehicle body, b is the compressive width of the critical structural section of the vehicle body, and k is the geometric coefficient of the structural beam.

[0013] Furthermore, the method for optimizing key factors includes: increasing the cavity cross-sectional area of ​​the key structural section of the vehicle body, adding reinforcing ribs and / or reinforcing partitions and / or multi-cavity structures to the cavity of the key load-bearing structural section of the vehicle body, changing the cavity shape of the key structural section of the vehicle body, and / or increasing the material thickness of the key structural section of the vehicle body.

[0014] Furthermore, the materials selected for the critical joint area and critical structural section of the vehicle body include: selecting one or more metallic materials with a tensile strength of not less than 780 MPa as the forming materials for the critical joint area and critical structural section of the vehicle body.

[0015] Furthermore, the present invention also designs a vehicle body structure designed by the aforementioned full-roof anti-pressure safety protection vehicle body structure design method, including a front bulkhead ring, a body pillar ring, a door ring, a floor ring, a roof ring, a wheel arch ring, a front end ring, a front longitudinal beam ring, and a front compartment ring.

[0016] The front circumference ring includes a ring structure formed by the upper front crossbeam, the Z-direction front beam, and the lower front crossbeam;

[0017] The vehicle body pillar ring includes multiple ring structures formed by the vehicle body pillar, the roof crossbeam, the front upper crossbeam, and the floor crossbeam.

[0018] The door ring includes multiple ring structures formed by the body pillars, roof longitudinal beams, front Z-direction beams, and door sill beams;

[0019] The floor ring includes multiple ring structures formed by a threshold beam and a floor crossbeam;

[0020] The top cover ring includes a ring structure formed by a top cover crossbeam and a top cover longitudinal beam;

[0021] The wheel cover ring includes a ring structure formed by an upper crossbeam, a lower arc-shaped beam, a wheel cover column, and a front Z-direction beam;

[0022] The front end ring includes a ring structure formed by a front anti-collision beam, a water tank upper crossbeam, and a front end column;

[0023] The front longitudinal beam ring includes a ring structure formed by the front longitudinal beam, the front anti-collision beam, and the lower crossbeam of the front bulkhead;

[0024] The front compartment ring includes a ring structure formed by the upper crossbeam of the water tank, the upper longitudinal beam of the front compartment, and the upper crossbeam of the front enclosure.

[0025] The beneficial effects of this invention are:

[0026] Precise protection under all working conditions significantly improves occupant safety: This invention identifies five typical stress conditions on the top of the vehicle body and strengthens them accordingly, breaking through the limitations of traditional "local reinforcement". Through the synergy of multi-cavity structure and ultra-high strength materials, it ensures the structural integrity of the occupant compartment under extreme rollover conditions, providing occupants with ample survival space and significantly improving passive safety performance.

[0027] Efficient and orderly force transmission, with superior body rigidity and NVH performance: This invention constructs multiple closed-loop force transmission paths, forming a "mesh skeleton" force flow dispersion system, avoiding stress concentration and significantly improving the overall torsional stiffness of the body; at the same time, it optimizes the structural vibration characteristics, effectively improving the noise and vibration performance of the vehicle under rough road conditions, and enhancing driving comfort.

[0028] Material and structural synergy design achieves a balance between safety and lightweight: The core force transmission path designed in this invention uses 1500MPa and 2000MPa grade hot-formed steel, while the secondary structure uses 780MPa grade advanced high-strength steel. The material efficiency is maximized through "precise material selection". Combined with multi-cavity cross-section optimization, the amount of material used is reduced while improving structural strength, thus solving the contradiction between safety and lightweight in traditional design.

[0029] The design is scientifically sound and practical, with broad scalability: This invention uses a digital design method based on topology optimization and sensitivity analysis, providing a clear theoretical basis for structural reinforcement; it is fully compatible with advanced processes such as thermoforming and hot gas forming, and the design scheme has strong engineering feasibility, making it suitable not only for off-road vehicles but also for civilian vehicles with high safety requirements. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments disclosed in this invention, the accompanying drawings of the embodiments will be briefly described below. These drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention.

[0031] Figure 1 This is a perspective view of the preferential stress area on the top of the vehicle body in working conditions one to five of this invention;

[0032] Figure 2 This is a three-dimensional schematic diagram of the continuous force transmission path for the full roof compression resistance in this invention;

[0033] Figure 3 This is a perspective view of the ring-shaped structure of the vehicle body in this invention;

[0034] Figure 4 This is a perspective view of the vehicle body structure in this invention;

[0035] Figure 5 This is a cross-sectional view of the front crossbeam of the top cover in this invention;

[0036] Figure 6 This is a cross-sectional view of column A in this invention;

[0037] Figure 7 This is a cross-sectional view of column B in this invention;

[0038] Figure 8 This is a cross-sectional view of column C in this invention;

[0039] Figure 9 This is a cross-sectional view of column D in this invention;

[0040] Figure 10 This is a cross-sectional view of the rear crossbeam of the top cover in this invention;

[0041] Figure 11 This is a partial enlarged view of the A-pillar joint area in this invention;

[0042] Figure 12 This is a partial enlarged view of the B-pillar joint area in this invention;

[0043] Figure 13 This is a partial enlarged view of the C-pillar joint area in this invention;

[0044] Figure 14 This is a partial enlarged view of the D-pillar joint area in this invention;

[0045] Figure 15 This is an exploded view of the distribution structure of hot-formed steel and advanced high-strength steel in this invention;

[0046] Figure 16 Flowchart of the design method for the full-roof anti-compression safety protection body structure of this invention

[0047] Among them, 1—front crossbeam of the roof, 2—A-pillar, 3—center top of the side panel, 4—D-pillar, 5—rear crossbeam of the roof, 6—top crossbeam of the side panel, 7—B-pillar, 8—C-pillar, 9—upper crossbeam of the front panel, 10—Z-direction beam of the front panel, 11—lower crossbeam of the front panel, 12—sill beam, 13—floor beam, 14—1500MPa hot-formed steel, 15—2000MPa hot-expansion tube beam, 16—2000MPa hot-formed steel. 17—Advanced high-strength steel pipe beam, 18—Advanced high-strength steel, 19—Front bulge ring, 20—Reinforced support plate, 21—A-pillar ring, 22—B-pillar ring, 23—C-pillar ring, 24—D-pillar ring, 25—Front door ring, 26—Rear door ring, 27—Front floor ring, 28—Rear floor ring, 29—Top cover ring, 30—Top cover longitudinal beam, 31—Front end ring, 32—Wheel cover ring, 33—Front longitudinal beam ring, 34—Front compartment ring. Detailed Implementation

[0048] The technical solutions (including preferred technical solutions) of the present invention will be further described in detail below with reference to the accompanying drawings and by way of listing some optional embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0049] Example 1

[0050] This invention provides an embodiment of a design method for a full-roof pressure-resistant safety protection body structure. This embodiment details the complete design process of the full-roof pressure-resistant safety protection body structure, such as... Figure 16 As shown, the specific steps are as follows:

[0051] Based on statistical and simulation analysis of real vehicle rollover accidents, five typical vehicle rollover scenarios are extracted: such as Figure 1 As shown, the following conditions are identified: Condition 1: Rollover condition where the front crossbeam 1 of the roof is the priority stress area; Condition 2: Rollover condition where the upper part of A-pillar 2 is the priority stress area; Condition 3: Rollover condition where the center of the top of the side wall 3 is the priority stress area; Condition 4: Rollover condition where the upper end of C-pillar 8 or D-pillar 4 is the priority stress area; Condition 5: Rollover condition where the rear crossbeam 5 of the roof is the priority stress area. For the above conditions, load boundary conditions are set (such as the peak value of the top impact load and the load application time under each condition). Through topology optimization, key stress areas such as A-pillar 2, B-pillar 7, roof crossbeam, and sill beam 12 are identified, and the target bearing capacity values ​​for each area are determined: the target bearing capacity values ​​for core load-bearing areas, such as the upper part of A-pillar 2 and the front crossbeam 1 of the roof, and the target bearing capacity values ​​for secondary load-bearing areas, such as C-pillar and the top of the side wall, ensuring that the passenger compartment does not deform excessively under extreme conditions.

[0052] Using the target bearing capacity value of the key stress area as input, and through topology optimization tools such as HyperWorks, Figure 2 As shown, the main force transmission path of "top cover → column → threshold beam → floor" is determined, and multiple sets of closed-loop structures are constructed, such as... Figure 3 As shown, it specifically includes: Basic ring structure: Front bulkhead ring 19 (formed by the front upper crossbeam 9, front Z-direction beam 10, and front lower crossbeam 11), body pillar ring (formed by the A / B / C / D pillars, roof crossbeam, front upper crossbeam 9, and floor crossbeam 13), door ring (formed by the body pillars, roof longitudinal beam 30, front Z-direction beam 10, and sill beam 12), floor ring (formed by the sill beam 12 and floor crossbeam 13), roof ring... 29 (formed by the top cover crossbeam and top cover longitudinal beam 30); auxiliary rings: wheel cover ring 32 (formed by the upper wheel cover crossbeam, lower wheel cover arc beam, wheel cover column, and front bulkhead Z-direction beam 10), front end ring 31 (formed by the front anti-collision beam, water tank upper crossbeam, and front end column), front longitudinal beam ring 33 (formed by the front longitudinal beam, front anti-collision beam, and front bulkhead lower crossbeam 11), and front compartment ring 34 (formed by the water tank upper crossbeam, front compartment upper longitudinal beam, and front bulkhead upper crossbeam 9). Each ring is smoothly connected via a three-way structure or box-shaped joint, forming a "mesh skeleton" force transmission system to ensure that impact energy is dispersed along multiple paths and to avoid localized stress concentration.

[0053] Key joint and structural section optimization: such as Figure 4 —14 As shown, (1) Optimization of key joints: For the core joint areas such as the joint on the A-pillar, the joint on the B-pillar, and the joint on the C-pillar / D-pillar, the following optimization methods are adopted: increase the bearing area (to improve connection stability); internal reinforcement (set through support components or reinforced partitions inside the joint to enhance torsional performance); smooth transition (such as optimizing the joint transition radius from R5mm to R15mm to reduce stress concentration and ensure smooth force transmission). (2) Optimization of key structural sections: Based on the load spectrum of five working conditions, mechanical simulation is carried out to identify key structural sections such as the front crossbeam 1 of the roof, A-pillar 2, and B-pillar 7. Through sensitivity analysis, key influencing factors such as "cavity cross-sectional area and number of internal stiffeners" are screened out. Among them, the sensitivity analysis is based on the calculation formula of the maximum crushing force of the key structural section of the vehicle body, and its expression is: ,in, This represents the maximum crushing force at the critical structural section of the vehicle body. Let A be the critical compressive stress of a single critical structural section of the vehicle body, and let A be the cross-sectional area of ​​that section. The formula for calculating the critical compressive stress of a single critical structural section of the vehicle body is as follows: Where E is the elastic modulus of the material of the key structural section of the vehicle body, ν is the Poisson's coefficient of the material of the key structural section of the vehicle body, t is the material thickness of the material of the key structural section of the vehicle body, b is the compressive width of the key structural section of the vehicle body, and k is the geometric coefficient of the structural beam. The optimization schemes are as follows: increase the cross-sectional area of ​​the cavities (e.g., increase the area of ​​the cavity in the front crossbeam of the roof, the cavity area of ​​the A-pillar, etc.); internal reinforcement (add reinforcing ribs to the cavities in each section, and adopt a multi-cavity design for some sections, such as the A-pillar, etc., to improve the bending modulus); shape optimization (e.g., change the traditional U-shaped section to a box-shaped section, etc., to improve the resistance to lateral pressure), increase the material thickness of the cross-section, etc.

[0054] Based on the stress distribution of each component, a "precise material selection" strategy is adopted, combined with advanced processes such as hot forming and hot air expansion, specifically as follows: Core force transmission paths, such as the front crossbeam 1 of the roof, the rear crossbeam 5 of the roof, A-pillar 2, and B-pillar 7, use 1500MPa grade hot-formed steel; Locally reinforced areas: such as... Figure 15 As shown, a 2000MPa-grade hot-expansion tube beam 15 is added inside the A-pillar 2, a 2000MPa-grade hot-formed patch plate 16 is installed on the inside of the B-pillar 7, and a 780MPa-grade advanced high-strength steel tube beam 17 is embedded inside the C-pillar 8; secondary structures, such as the side panel outer panel and the rear floor crossbeam, use 780MPa-grade advanced high-strength steel 17, which reduces the weight of the vehicle body while ensuring strength, thereby increasing the proportion of high-strength steel used in the whole vehicle.

[0055] A CAE model of the entire vehicle body structure was constructed, and the following verification steps were taken to ensure performance compliance: Safety protection verification: Five rollover scenarios were simulated using software such as LS-DYNA to ensure that passenger compartment intrusion and roof crush load-bearing capacity met requirements. A multi-objective optimization algorithm was used to control the vehicle weight within a set value while meeting safety performance requirements, achieving a "safety-weight" balance. The torsional stiffness of the vehicle body was tested to ensure improvement over traditional structures and enhanced NVH performance. If the verification results did not meet the requirements, the process was repeated iteratively until all performance indicators met the requirements (e.g., readjusting the A-pillar cavity area or material strength).

[0056] Example 2

[0057] This embodiment provides a vehicle body structure obtained by the design method of Embodiment 1.

[0058] like Figure 3 As shown, the vehicle frame comprises eight sets of closed rings, which work together to form a continuous force transmission network:

[0059] Front circumference ring 19: formed by the upper front crossbeam 9, the Z-direction front beam 10, and the lower front crossbeam 11.

[0060] Body pillar rings: including A-pillar ring 21, B-pillar ring 22, C-pillar ring 23, and D-pillar ring 24. A-pillar ring 21 is formed by A-pillar 2, front roof crossbeam 1, front upper crossbeam 9, and floor crossbeam 13; B-pillar ring 22 is formed by B-pillar 7, roof crossbeam, and floor crossbeam 13; C-pillar ring 23 is formed by C-pillar 8, roof crossbeam, and floor crossbeam; D-pillar ring 24 is formed by D-pillar 4, rear roof crossbeam 5, and floor crossbeam 13.

[0061] Door rings: divided into front door ring 25 and rear door ring 26. Front door ring 25 is formed by A-pillar 21, B-pillar 22, roof longitudinal beam 30, and door sill beam 12. Rear door ring 26 is formed by B-pillar 22, C-pillar 8, roof longitudinal beam 30, and door sill beam 12.

[0062] Floor ring: Includes front floor ring 27 and rear floor ring 28, which are formed by sill beam 12 and floor crossbeam 13 to enhance the chassis load-bearing capacity.

[0063] Top cover ring 29: formed by the front crossbeam 1, the rear crossbeam 5, and the longitudinal beam 30 of the top cover.

[0064] Auxiliary rings: wheel arch ring 32, front end ring 31, front longitudinal beam ring 33, and front compartment ring 34. Among them, the wheel arch ring 32 is formed by the upper wheel arch crossbeam, the lower wheel arch arc beam, the wheel arch pillar, and the front bulkhead Z-direction beam 10; the front end ring 31 is formed by the front anti-collision beam, the upper water tank crossbeam, and the front end pillar; the front longitudinal beam ring 33 is formed by the front longitudinal beam, the front anti-collision beam, and the lower front bulkhead crossbeam 11; the front compartment ring 34 is formed by the upper water tank crossbeam, the upper front compartment longitudinal beam, and the upper front bulkhead crossbeam 9.

[0065] The combined effect of the aforementioned ring structures ensures passenger space, occupant safety, and overall vehicle rigidity during rollover.

[0066] In summary, this invention firstly overcomes the limitations of traditional "local reinforcement" by systematically covering five top-load conditions, achieving precise protection under all conditions and ensuring the structural integrity of the passenger compartment under extreme rollover conditions. Secondly, it constructs a closed-loop force transmission path, forming a "mesh skeleton" force flow dispersion system to avoid stress concentration, significantly improving the torsional stiffness of the vehicle body and optimizing NVH performance, thus enhancing ride comfort. Furthermore, it adopts a material and structural synergy design of "ultra-high-strength steel + multi-cavity structure," effectively controlling the vehicle body weight while strengthening safety performance, resolving the prominent contradiction between safety and lightweighting in traditional designs. Finally, based on the deep integration of digital simulation and advanced processes, the design scheme has a scientific basis and mass production feasibility, making it suitable not only for off-road vehicles but also for civilian vehicles with high safety requirements, with broad application prospects.

[0067] It should be noted that the above description of the technical solutions is exemplary, and this specification may be embodied in different forms and should not be construed as limiting it to the technical solutions set forth herein. Rather, providing these descriptions will ensure that the disclosure of this invention is thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Furthermore, the technical solutions of this invention are defined only by the scope of the claims.

[0068] When using the terms “comprising,” “having,” and “including” as described in this specification, there may also be another part or other parts, and the terms used are generally singular but may also be plural.

[0069] Finally, it should be noted that the above embodiments are merely representative examples of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention should be considered within the protection scope of the present invention.

Claims

1. A method for designing a full-roof, pressure-resistant safety protection vehicle body structure, characterized in that: It includes: Establish typical vehicle rollover conditions, set load boundary conditions for typical vehicle rollover conditions, and determine the target bearing pressure values ​​for key stress areas of the vehicle body. Based on the target bearing pressure value of the key stress area, the main force transmission path of the typical vehicle rollover condition is determined by topology optimization, and a closed ring structure of the vehicle body is constructed. Based on the closed-loop structure of the vehicle body, the key joint areas and key structural sections of the vehicle body are identified and optimized. Based on the molding process and stress distribution, the molding materials for the critical joint areas and critical structural sections of the vehicle body are selected. Construct and verify whether the vehicle body structure with optimized and selected materials, including the critical joint area of ​​the vehicle body, the critical structural section of the vehicle body, and the closed ring structure of the vehicle body, meets the safety protection and weight balance requirements of the typical vehicle rollover condition.

2. The full-roof compression-resistant safety protection body structure design method as described in claim 1, characterized in that: The typical vehicle rollover conditions include: the front crossbeam of the roof (1) is the rollover condition of the vehicle top priority stress area; the upper part of the A-pillar (2) is the rollover condition of the vehicle top priority stress area; the center of the top of the side panel (3) is the rollover condition of the vehicle top priority stress area; the upper end of the C-pillar (8) or the upper end of the D-pillar (4) is the rollover condition of the vehicle top priority stress area; and the rear crossbeam of the roof (5) is the rollover condition of the vehicle top priority stress area.

3. The full-roof compression-resistant safety protection body structure design method as described in claim 2, characterized in that: The closed-loop structure of the vehicle body includes: constructing multiple ring-shaped force transmission paths formed by the front body bulkhead, body pillars, roof beam, sill beam (12), floor beam, front anti-collision beam, water tank upper crossbeam, front pillar, front longitudinal beam, wheel arch beam, wheel arch pillar and front compartment upper longitudinal beam.

4. The full-roof compression-resistant safety protection body structure design method as described in claim 3, characterized in that: Methods for identifying and optimizing critical joint areas of the vehicle body include: increasing the load-bearing area of ​​the joint areas of the multiple annular force transmission paths, setting through-support members and / or reinforcing partitions inside the joint areas, extending the overlap length between the joint areas and adjacent components, and smoothing the transition rounded corners of the joint areas.

5. The full-roof pressure-resistant safety protection body structure design method as described in claim 3, characterized in that: The method for identifying and optimizing the structure of key structural sections of the vehicle body includes: performing mechanical simulation analysis on the whole vehicle body structure based on the load spectrum of the typical vehicle body rollover condition, simulating the force flow transmission path, and identifying key structural sections of the vehicle body.

6. The full-roof compression-resistant safety protection body structure design method as described in claim 5, characterized in that: The method for identifying and optimizing the cross-section of the key structure of the vehicle body further includes: conducting sensitivity analysis on the factors affecting the load-bearing capacity of the key structure of the vehicle body, screening out the influencing factors related to the load-bearing capacity of the key structure of the vehicle body as key factors affecting the load-bearing capacity of the key structure of the vehicle body, and optimizing the key factors.

7. The full-roof compression-resistant safety protection body structure design method as described in claim 6, characterized in that: The method for conducting sensitivity analysis on factors affecting the load-bearing capacity of the key body structure, and screening out influencing factors related to the load-bearing capacity of the key body structure as key factors affecting the load-bearing capacity of the key body structure, and optimizing the key factors includes: based on the calculation formula of the maximum crushing force of the cross-section of the key body structure, screening out influencing factors related to the maximum crushing force of the cross-section of the key body structure as key factors affecting the load-bearing capacity of the key body structure, and optimizing the key factors; the expression of the calculation formula of the maximum crushing force of the cross-section of the key body structure is: ,in, This represents the maximum crushing force at the critical structural section of the vehicle body. Let A be the critical compressive stress of a single critical structural section of the vehicle body, and let A be the cross-sectional area of ​​that section. The formula for calculating the critical compressive stress of a single critical structural section of the vehicle body is as follows: Where E is the elastic modulus of the material of the critical structural section of the vehicle body, ν is the Poisson's coefficient of the material of the critical structural section of the vehicle body, t is the material thickness of the material of the critical structural section of the vehicle body, b is the compressive width of the critical structural section of the vehicle body, and k is the geometric coefficient of the structural beam.

8. The full-roof compression-resistant safety protection body structure design method as described in claim 7, characterized in that: The method for optimizing key factors includes: increasing the cavity cross-sectional area of ​​the key structural section of the vehicle body, adding reinforcing ribs and / or reinforcing partitions and / or multi-cavity structures to the cavity of the key load-bearing structural section of the vehicle body, changing the cavity shape of the key structural section of the vehicle body, and / or increasing the material thickness of the key structural section of the vehicle body.

9. The design method for a full-roof compression-resistant safety protection vehicle body structure as described in claim 1, characterized in that: The materials selected for the critical joint area and critical structural section of the vehicle body include: selecting one or more metallic materials with a tensile strength of not less than 780 MPa as the forming materials for the critical joint area and critical structural section of the vehicle body.

10. A vehicle body structure designed using the full-roof compression-resistant safety protection body structure design method according to any one of claims 1-9, characterized in that: It includes a front bulkhead ring (19), a body pillar ring, a door ring, a floor ring, a roof ring (29), a wheel arch ring (32), a front end ring (31), a front longitudinal beam ring (33), and a front compartment ring (34). The front circumference ring (19) includes a ring structure formed by the upper front circumference crossbeam (9), the front circumference Z-direction beam (10), and the lower front circumference crossbeam (11); The vehicle body pillar ring includes multiple ring structures formed by the vehicle body pillar, the roof crossbeam, the front upper crossbeam (9), and the floor crossbeam (13); The door ring includes multiple ring structures formed by the body pillars, roof longitudinal beams (30), front Z-direction beams (10), and door sill beams (12); The floor ring includes multiple ring structures formed by a threshold beam (12) and a floor crossbeam (13); The top cover ring (29) includes a ring structure formed by the top cover crossbeam and the top cover longitudinal beam (30); The wheel cover ring (32) includes a ring structure formed by the upper crossbeam of the wheel cover, the lower arc beam of the wheel cover, the wheel cover column and the front Z-direction beam (10); The front end ring (31) includes a ring structure formed by the front anti-collision beam, the upper crossbeam of the water tank and the front end column; The front longitudinal beam ring (33) includes a ring structure formed by the front longitudinal beam, the front anti-collision beam and the front lower crossbeam (11); The front compartment ring (34) includes a ring structure formed by the upper crossbeam of the water tank, the upper longitudinal beam of the front compartment, and the upper crossbeam of the front enclosure (9).

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