A safety design method for the third row structure in rear-end collision

Abstract

The present invention relates to the technical field of automobile parts, and discloses a third-row structural safety design method in a rear-end collision, comprising the following steps: step one, force transmission path design; step two, energy absorption design; total momentum calculation before and after the collision; energy conversion during the collision, energy conversion calculation during the collision; energy conversion during the collision, as the weight of the truck increases, the energy absorption increases, and when the truck is more than 10T, the energy absorption tends to stabilize at 25%. The present invention effectively guides the force generated during the collision by clarifying the upper, middle and lower parts of the three force transmission paths, thereby reducing the impact on passengers, providing additional support in the collision, and improving stability. The energy absorption ratio of 25% in the design ensures that the vehicle can absorb a certain amount of energy during the collision, reducing the kinetic energy transmitted to the passengers, and achieving the beneficial effect of solving the problem of low safety of the third row.

Description

Technical Field

[0001] The invention relates to the technical field of automobile parts, and in particular to a third-row structural safety design method in a rear-end collision. Background Art

[0002] So far, there are no regulatory requirements for the safety of three-row passengers in large and medium-sized vehicles with third-row seats, and none of the OEMs have focused on their development.

[0003] Nowadays, families with many children often go on self-driving trips, and most of them drive medium to large vehicles with three rows of seats. However, most consumers are worried about the low safety performance of the third row. In order to solve the problem of low safety of third-row passengers, especially the problem of structural crashworthiness (large intrusion) under rear-end collision of heavy trucks, and to preserve the lives of the three-row passengers, this invention is used to obtain ultra-low or zero intrusion volume in the three-row passenger space. Summary of the invention

[0004] 1. Technical issues to be resolved In view of the shortcomings of the prior art, the present invention provides a method for designing the third-row structural safety in a rear-end collision, which is capable of solving the problem of low safety of third-row passengers, achieving the advantages of ultra-low or zero intrusion into the three-row passenger space, and solving the problems of the above-mentioned technologies.

[0005] (II) Technical solution To achieve the above object, the present invention provides the following technical solution: a third row structural safety design method in a rear-end collision, comprising the following steps: Step 1: Design of force transmission paths: three upper force transmission paths, a middle force transmission path and a lower force transmission path; the three upper force transmission paths are CD pillars, rear wheel housings and upper side beams, the middle force transmission path is the rear longitudinal beam, and the lower force transmission path is the subframe and rear tire; Step 2: Energy absorption design: Based on the conservation of energy and momentum, the structure of the impacted vehicle is matched with a maximum energy absorption ratio of 25%; total energy 100% = remaining kinetic energy 67.5%~75% + absorbed energy 22.5%~25%.

[0006] Preferably, the total momentum before and after the collision is calculated as: ; in: is the initial velocity, is the separation speed of the two vehicles after rear-end collision, For the quality of the truck, is the mass of the vehicle hit; Energy conversion during collision, calculation of energy conversion during collision: ; Energy conversion during the collision: As the weight of the truck increases, the energy absorption increases. When the truck is over 10 tons, the energy absorption tends to stabilize at 25%. The energy conversion during the collision is calculated as:

[0007] in: is the total energy: calculated according to the energy conservation relationship; is a constant, which represents the energy absorption per unit mass and reflects the influence of weight on energy absorption.

[0008] Preferably, the energy conversion calculation formula in the collision process is It means that the absorbed energy is proportional to the mass of the truck, which means that as the mass increases, the absorbed energy also gradually increases; The energy conversion calculation formula in the collision process is It indicates that the absorbed energy reaches a stable value, fixed at a level of 25% of the total energy, indicating that even if the mass of the truck increases further, the absorbed energy will not increase significantly.

[0009] Preferably, the energy conversion during the collision is substituted into The kinetic energy after the collision is calculated using the formula:

[0010] Substitution The expression is:

[0011] Combining the two: .

[0012] Preferably, the energy absorption is calculated as:

[0013] in: It represents the energy absorbed by two vehicles during a collision and is used to understand the loss and safety of a collision.

[0014] Preferably, the stress calculation in step 1 is:

[0015] in: for stress; is the applied force; is the force-bearing cross-sectional area.

[0016] Preferably, in step 1, the bending stress of the rear longitudinal beam and the upper side beam is calculated as:

[0017] in: is the bending stress; is the bending moment; is the distance from the neutral axis to the outer fiber; is the section moment of inertia.

[0018] Preferably, the deflection in step 1 is calculated as:

[0019] in: is the deflection; is the applied force; is the length of the beam; is the Young’s modulus of the material; is the section moment of inertia.

[0020] Preferably, the transfer path is calculated as follows: three upper force transfer paths: CD column, rear wheel cover and upper side beam: Using the above stress formula Calculate the stress for each path; The force transmission path in the middle: rear longitudinal beam, calculate the bending stress: ; Calculate the deflection: ; The lower force path: subframe and rear tire, is calculated using the same stress and deflection formulas.

[0021] Preferably, the total energy in step 2 is calculated as:

[0022] in: is the total energy; is the remaining kinetic energy after the collision; is the energy absorbed during the collision.

[0023] Compared with the prior art, the present invention provides a third-row structural safety design method in a rear-end collision, which has the following beneficial effects: 1. The third row structural safety design method in the rear-end collision effectively guides the force generated during the collision by clarifying the three force transmission paths, namely the upper, middle and lower parts, so as to reduce the impact on the passengers. The upper force transmission path: CD column, rear wheel cover, upper side beam, can quickly disperse the collision force; the middle force transmission path: rear longitudinal beam, responsible for the main energy transmission; the lower force transmission path: subframe and rear tire, provide additional support in the collision and improve stability. The energy absorption ratio of 25% in the design ensures that the vehicle can absorb a certain amount of energy during the collision and reduce the kinetic energy transmitted to the passengers: through the principles of conservation of energy and conservation of momentum, the maximum energy absorption in the collision is achieved to protect the passengers; the total energy is divided into residual kinetic energy and absorbed energy to ensure that the design can effectively resist collisions of different intensities; stress, bending stress and deflection analysis are used to ensure that each component can withstand the real-time applied force during the design process. As the weight of the truck increases, the increase in energy absorption ensures that the passengers can still be effectively protected in the event of a large impact. This mechanism ensures that the safety of the third row passengers is still guaranteed even in heavy collisions, achieving the beneficial effect of solving the problem of low safety of the third row.

[0024] 2. The third-row structural safety design method in the rear-end collision protects the third-row passengers without affecting the passenger compartment space by concentrating energy absorption on specific parts of the vehicle structure. For vehicles with a mass greater than 10 tons, after reaching a stable energy absorption, even if the vehicle continues to increase in weight, the increase in energy absorption is limited, ensuring that even in a heavy collision, the passenger space will not be significantly invaded. By identifying and optimizing the upper, middle and lower force transmission paths: CD pillars, rear longitudinal beams, and subframes, it is ensured that during the collision, the force is transmitted along the most effective path to reduce the impact on the third-row passenger space. The bending stress and deflection analysis formula is used to perform stress and deflection analysis to ensure that key structural parts such as the rear longitudinal beam and upper side beam can withstand the necessary force without significant deformation in the collision, thereby protecting the passenger space from invasion and achieving the beneficial effect of obtaining ultra-low or zero intrusion into the three-row passenger space. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the steps of the present invention. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] See also Figure 1, a third row structural safety design method in a rear-end collision, comprising the following steps: Step 1: Design of force transmission paths: three upper force transmission paths, a middle force transmission path and a lower force transmission path; the three upper force transmission paths are CD pillars, rear wheel housings and upper side beams, the middle force transmission path is the rear longitudinal beam, and the lower force transmission path is the subframe and rear tire; Step 2: Energy absorption design: Based on the conservation of energy and momentum, the structure of the impacted vehicle is matched with a maximum energy absorption ratio of 25%; total energy 100% = remaining kinetic energy 67.5%~75% + absorbed energy 22.5%~25%; Calculation of total momentum before and after collision: ; in: is the initial velocity, is the separation speed of the two vehicles after rear-end collision, For the quality of the truck, is the mass of the vehicle hit; Energy conversion during collision, calculation of energy conversion during collision: ; Energy conversion during the collision: As the weight of the truck increases, the energy absorption increases. When the truck is over 10 tons, the energy absorption tends to stabilize at 25%.

[0028] Optimize energy transmission: Through clearly designed force transmission paths, such as CD pillars, rear wheel arches and upper side beams, ensure that collision energy can be transmitted along the predetermined path, thereby reducing the intrusion into passenger space.

[0029] Enhance vehicle rigidity: The rationally arranged force transmission path improves the overall structural strength of the vehicle, making it more able to withstand the impact of a collision, thereby enhancing the safety of the passenger compartment.

[0030] Reduce local damage: Effective force transmission path design helps reduce damage to local structures during collisions and further protect the safety of occupants.

[0031] Effective energy absorption: By setting the energy absorption ratio, this design ensures that the vehicle can absorb a certain proportion of energy during a collision, reducing the impact on passengers.

[0032] Maintain kinetic energy balance: Rationally manage the remaining kinetic energy and absorb energy in a collision to make the design more efficient and thus ensure the safety of passengers.

[0033] Flexible response to different situations: Based on the energy absorption design, it can maintain safety in various collision scenarios and improve safety performance.

[0034] Accurate collision simulation: By analyzing the momentum changes before and after the collision, the impact of the collision on various parts of the vehicle can be more accurately predicted during the design phase, helping to optimize the structural design.

[0035] Adaptable to different mass combinations: This analysis method can be applied to various vehicles and collision situations to ensure scientific and reasonable design.

[0036] Dynamic Assessment of Energy Management: The conversion of collision energy is evaluated during design to help identify how energy is absorbed and lost in a collision in order to optimize energy-absorbing structures.

[0037] Improving energy absorption efficiency: By understanding how energy changes during a crash, designers can improve energy absorption efficiency, helping to protect passengers.

[0038] Increased adaptability: As truck weight increases, energy absorption tends to level off, which means heavier models are more likely to be designed to offer greater protection.

[0039] Responding to high-intensity collisions: This design ensures that the vehicle can still effectively protect passengers and reduce potential injuries when facing heavy collisions.

[0040] Preferably, the energy conversion during the collision is calculated as:

[0041] in: is the total energy: calculated according to the energy conservation relationship; is a constant, which represents the energy absorption per unit mass and reflects the influence of weight on energy absorption.

[0042] Adjust the energy absorption strategy according to the vehicle weight: By setting the constant K, the energy absorption for different vehicle weights is dynamically adjusted to ensure the optimal energy absorption effect on container trucks of different weights.

[0043] Enhanced design flexibility: This approach allows designers to adjust the energy absorption strategy based on the specific mass of the vehicle (for example, whether it exceeds 10 tons), making the design more flexible and improving safety.

[0044] Scientific and reasonable energy assessment: By establishing the relationship between absorbed energy and total energy based on the principle of conservation of energy, the entire design is more in line with physical laws, thereby improving the credibility of safety design.

[0045] Facilitates design optimization: Such a design can help engineers more clearly understand how energy is converted in a collision, and make improvements based on this to ensure effective energy management.

[0046] For various collision scenarios: Use different energy absorption formulas to deal with vehicles of different masses (less than 10 tons and greater than or equal to 10 tons), ensuring that no matter what the situation, there will be appropriate energy absorption design to deal with potential collision damage.

[0047] Increased passenger safety: Through targeted designs of heavy and light trucks, passengers can be protected from greater injuries to the greatest extent possible, especially in heavy collisions.

[0048] Deeper performance analysis: Setting the K constant helps clarify the specific impact of weight changes on energy absorption performance. This analysis provides valuable basis for subsequent design iterations.

[0049] Improve design reliability: Understanding how changes in vehicle quality affect safety helps engineering teams make scientific and reasonable optimizations to improve design reliability and safety.

[0050] Highly efficient response to heavy collisions: For vehicles with a mass of 10 tonnes or more, the relative stability of energy absorption is ensured, which means that the vehicle is designed to provide effective protection for the occupants even in high-intensity collisions.

[0051] Enhanced overall safety: Stable energy absorption is particularly good in accidents, significantly improving overall passenger safety Preferably, the energy conversion calculation formula in the collision process is It means that the absorbed energy is proportional to the mass of the truck, which means that as the mass increases, the absorbed energy also gradually increases; The energy conversion calculation formula in the collision process is It indicates that the absorbed energy reaches a stable value, fixed at a level of 25% of the total energy, indicating that even if the mass of the truck increases further, the absorbed energy will not increase significantly.

[0052] Preferably, the energy conversion during the collision is substituted into The kinetic energy after the collision is calculated using the formula:

[0053] Substitution The expression is:

[0054] Combining the two: .

[0055] Assessing the consequences of a collision: This formula helps understand the impact of a collision on the vehicle and its occupants. By calculating kinetic energy, it further analyzes how energy is converted into injury in a collision, guiding safety design.

[0056] Improve the effectiveness of occupant protection design: Combine kinetic energy calculation with vehicle structure design to better evaluate and optimize the effect of collision energy absorption structure and enhance occupant protection.

[0057] Improved usability in engineering practice: The formula provides a practical method that engineers can directly apply when conducting safety assessments and vehicle design. Through simple mathematical operations, the necessary crash-related data can be obtained in real time.

[0058] Facilitates education and knowledge dissemination: Since the formulas are relatively simple and intuitive, they help learners and practitioners quickly get started in the training and education of vehicle safety and crash mechanics.

[0059] Preferably, the energy absorption is calculated as:

[0060] in: It represents the energy absorbed by two vehicles during a collision and is used to understand the loss and safety of a collision.

[0061] Clear reflection of energy conversion: The formula clarifies the relationship between the initial kinetic energy and the kinetic energy after the collision, thus clearly showing the energy converted into forms such as heat energy and deformation energy during the collision.

[0062] Facilitates loss assessment: By calculating the energy absorption, the energy loss during the collision can be assessed, which is crucial to understanding the severity of the accident.

[0063] Provides a basis for safety design: By calculating the energy absorbed during a collision, designers adjust the vehicle structure to improve safety and ensure maximum protection for occupants in an accident.

[0064] Helps design energy-absorbing components: Understanding how much energy a vehicle absorbs in a crash can help design components (such as bumpers and body structures) with energy-absorbing properties, thereby reducing the impact of an accident on occupants.

[0065] Easy to apply in engineering design: The formula is simple and easy to operate. Engineers use it as a design and analysis tool and apply it directly in calculation software to improve work efficiency.

[0066] Guide crash simulations: The calculated energy absorption is used to verify and calibrate the accuracy of crash simulation software, ensuring consistency between simulation results and actual crash behavior, leading to improved design iterations.

[0067] Applicable to a variety of collision scenarios: Whether it is a collision between small cars or a collision between heavy cars and light cars, this formula can be used to effectively evaluate them, thereby improving its versatility.

[0068] Facilitates sensitivity analysis: By adjusting parameters such as vehicle mass and speed, sensitivity analysis can be performed under different scenarios to help designers understand the most critical design factors.

[0069] Strengthen the understanding of vehicle structure: Through the calculation of energy absorption, we can deeply understand the response of different structures to collision energy, so that designers can optimize the vehicle structure in a targeted manner.

[0070] Reduced accident injuries: Explicit assessment of energy absorption helps designers achieve higher requirements in vehicle safety standards, reducing the risk of occupants being injured in an accident.

[0071] Providing data for accident consequence assessment: The calculation of energy absorption provides necessary data support for analyzing accident results and helps relevant departments conduct accident investigation and research.

[0072] Contribute to the formulation of regulations and standards: By standardizing the calculation of energy absorption, it provides a scientific basis for the formulation of automobile safety regulations and promotes the overall improvement of traffic safety. Preferably, the stress calculation in step 1 is:

[0073] in: for stress; is the applied force; is the force-bearing cross-sectional area.

[0074] Preferably, in step 1, the bending stress of the rear longitudinal beam and the upper side beam is calculated as:

[0075] in: is the bending stress; is the bending moment; is the distance from the neutral axis to the outer fiber; is the section moment of inertia.

[0076] Preferably, the deflection in step 1 is calculated as:

[0077] in: is the deflection; is the applied force; is the length of the beam; is the Young’s modulus of the material; is the section moment of inertia.

[0078] Preferably, the transfer path is calculated as follows: three upper force transfer paths: CD column, rear wheel cover and upper side beam: Using the above stress formula Calculate the stress for each path; The force transmission path in the middle: rear longitudinal beam, calculate the bending stress: ; Calculate the deflection: ; The lower force path: subframe and rear tire, is calculated using the same stress and deflection formulas.

[0079] Preferably, the total energy in step 2 is calculated as:

[0080] in: is the total energy; is the remaining kinetic energy after the collision; is the energy absorbed during the collision.

[0081] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for designing the third row structure safety in a rear-end collision, characterized in that: The following steps are involved: Step 1: Design of force transmission paths: three upper force transmission paths, a middle force transmission path and a lower force transmission path; the three upper force transmission paths are CD pillars, rear wheel housings and upper side beams, the middle force transmission path is the rear longitudinal beam, and the lower force transmission path is the subframe and rear tire; Step 2: Energy absorption design: Based on the conservation of energy and momentum, the structure of the impacted vehicle is matched with a maximum energy absorption ratio of 25%; total energy 100% = remaining kinetic energy 67.5%~75% + absorbed energy 22.5%~25%.

2. A third row structural safety design method for rear-end collision according to claim 1, characterized in that: The designed method also includes: calculation of total momentum before and after collision: ; in: is the initial velocity, is the separation speed of the two vehicles after rear-end collision, For the quality of the truck, is the mass of the vehicle hit; Calculation of energy conversion during the collision: ； As the weight of the truck increases, the energy absorption increases. When the truck is over 10 tons, the energy absorption tends to stabilize at 25%. The energy conversion during the collision is calculated as: in: is the total energy: calculated according to the energy conservation relationship; is a constant, which represents the energy absorption per unit mass and reflects the influence of weight on energy absorption.

3. A third row structural safety design method for rear-end collision according to claim 2, characterized in that: The energy conversion calculation formula in the collision process is It means that the absorbed energy is proportional to the mass of the truck, which means that as the mass increases, the absorbed energy also gradually increases; The energy conversion calculation formula in the collision process is It indicates that the absorbed energy reaches a stable value, fixed at a level of 25% of the total energy, indicating that even if the mass of the truck increases further, the absorbed energy will not increase significantly.

4. The third row structural safety design method in a rear-end collision according to claim 3, characterized in that: Substitute the energy conversion in the collision process into The kinetic energy after the collision is calculated using the formula: Substitution The expression is: Combining the two: .

5. A method for designing the third row structure safety in a rear-end collision according to claim 4, characterized in that: The energy absorption is calculated as: in: It represents the energy absorbed by two vehicles during a collision and is used to understand the loss and safety of a collision.

6. A third row structural safety design method for rear-end collision according to claim 5, characterized in that: The stress calculation in step 1 is: in: for stress; is the applied force; is the force-bearing cross-sectional area.

7. A third row structural safety design method for rear-end collision according to claim 6, characterized in that: In step 1, the bending stress of the rear longitudinal beam and the upper side beam is calculated as: in: is the bending stress; is the bending moment; is the distance from the neutral axis to the outer fiber; is the section moment of inertia.

8. The third row structural safety design method for rear-end collision according to claim 7, characterized in that: The deflection in step 1 is calculated as: in: is the deflection; is the applied force; is the length of the beam; is the Young’s modulus of the material; is the section moment of inertia.

9. A third row structural safety design method for rear-end collision according to claim 8, characterized in that: The transfer path is calculated as follows: Three upper force transfer paths: CD column, rear wheel cover and upper side beam: Using the above stress formula Calculate the stress for each path; The force transmission path in the middle: rear longitudinal beam, calculate the bending stress: ; Calculate the deflection: ; The lower force path: subframe and rear tire, is calculated using the same stress and deflection formulas.

10. A third row structural safety design method for rear-end collision according to claim 9, characterized in that: The total energy in step 2 is calculated as: in: is the total energy; is the remaining kinetic energy after the collision; is the energy absorbed during the collision.

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