Side Sill Reinforcement Layout for Controlled Side-Impact Compression
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Solution Overview
Problem
Existing vehicle-body structures face issues with unintended deformation of reinforcement members in side collisions, leading to a loss in energy absorption, particularly in electric vehicles where battery packs are vulnerable.
Innovation Solution
A lower vehicle-body structure featuring a pair of side sills with a main reinforcement and sub-reinforcement, including deformation promoting portions that ensure axial compression of sub-closed-cross-sections during a side collision, thereby increasing energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a reinforcement member with M-shaped cross section is provided in the side sill, then energy absorption capability is improved, but unintended deformation occurs causing loss of energy absorption efficiency
Solution Approach 1:
The reinforcement member is divided into multiple segments: the main reinforcement (first reinforcement) with hat-shaped cross section and the sub-reinforcement (second reinforcement) with closed cross section. This segmentation allows each component to perform specific functions - the main reinforcement provides overall structural support while the sub-reinforcement ensures controlled deformation and consistent energy absorption through its closed cross-section geometry.
Solution Approach 2:
Different portions of the reinforcement structure are given different properties. The main reinforcement has a hat-shaped cross section optimized for carrying axial loads, while the sub-reinforcement has a closed cross section specifically designed to control local deformation. The deformation promoting portion is strategically placed to initiate controlled deformation at a specific location, ensuring the sub-reinforcement deforms as intended rather than unpredictably.
2Loss of energy
If the reinforcement member is made with closed cross-section, then energy absorption is enhanced, but deformation may deviate in up-down direction reducing compression effectiveness
Solution Approach 1:
The sub-reinforcement acts as an intermediary element between the main reinforcement and the deformation promoting portion. Its closed cross-section geometry serves as a mediator that translates the deformation force into controlled axial compression, preventing the main reinforcement from deforming in unintended up-down directions while still enabling effective energy absorption through the sub-closed-cross-sections.
3Reliability
If deformation promoting portion is added to control deformation, then energy absorption reliability is improved, but structural complexity increases
Solution Approach 1:
The deformation promoting portion is merged with the side sill inner portion, forming an integrated structure rather than a separate component. This merging reduces the number of discrete parts while still achieving the function of controlling deformation. The corner portion of the side sill inner portion itself serves as the deformation promoting feature, eliminating the need for additional separate deformation control elements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The structure effectively increases energy absorption in side collisions by restricting unintended deformation, ensuring efficient energy dissipation and protecting onboard components like battery packs.
Implementation Method 1
the side sill inner portion includes a deformation promoting portion to be deformed inward of the side sill in a side collision of the vehicle
Implementation Method 2
the sub-reinforcement forms a plurality of sub-closed-cross-sections, which are arranged in the vehicle front-rear direction, in cooperation with the first wall when viewed in a side view of the vehicle
Implementation Method 3
the hollow closed cross-section formed by the two protruding portions of the reinforcement member, which has a substantially M-shaped cross section, is compressed in the vehicle width direction in a side collision, thus absorbing energy
Data Source
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AI summary
[Problem] To provide a lower vehicle-body structure of a vehicle that can certainly increase an amount of energy absorption in a side collision. [Means for Solution] A vehicle body 1 includes a first reinforcement 5 (main reinforcement) and a third reinforcement 7 (sub-reinforcement) which are disposed in a closed cross-section 2a of a side sill 2. The first reinforcement 5 has a hat shape which includes an upper wall 5a (second wall), a lower wall 5b (first wall), and a vertical wall 5c extending in an up-down direction. The third reinforcement 7 forms a plurality of second closed cross-sections 9 (sub-closed-cross-sections) in cooperation with the lower wall 5b. The third reinforcement 7 is disposed on a lower surface 5b1 of the lower wall 5b. The side sill inner portion 22 includes a corner portion 22b3 that is a deformation promoting portion 24 to be deformed inward of the side sill 2 in a side collision of a vehicle in such a way as to be brought into contact with the third reinforcement 7 from the outer side in the up-down direction.