Closed-Section Side Sill Reinforcement for Lightweight Crash Absorption
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Solution Overview
Problem
The existing side sills for eco-friendly vehicles, particularly those with batteries, face challenges in efficiently absorbing collision energy while maintaining a lightweight and cost-effective design, as they need to operate in a narrow space with limited weight reduction and increased rigidity.
Innovation Solution
A side sill design incorporating a hollow frame with overlapping first and second reinforcing frames made of steel, forming a closed cross-section, which includes concave-convex portions and specific flange and extension configurations for enhanced collision energy absorption and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If aluminum extrusion materials are applied to the side sill, then weight is reduced, but collision energy absorption ability is insufficient
Solution Approach 1:
The side sill employs a composite structure combining aluminum extrusion frame with steel reinforcing frames. The aluminum frame provides lightweight properties while the steel reinforcing frames embedded within the hollow portions provide high strength and collision energy absorption capability, resolving the contradiction between weight reduction and strength enhancement
Solution Approach 2:
The steel reinforcing frames are nested within the hollow portions of the aluminum extrusion frame. This nested configuration allows the steel reinforcement to be integrated inside the aluminum structure, achieving both weight reduction from the aluminum outer frame and strength enhancement from the inner steel reinforcement without significantly increasing overall volume
2Volume of moving object
If the side space is reduced to accommodate batteries, then vehicle width is reduced, but collision energy absorption space is limited
Solution Approach 1:
The hollow portions of the aluminum extrusion frame are strategically designed with varying cross-sectional areas along the longitudinal direction. The hollow portions are positioned to provide adequate deformation space during side collisions while maintaining a compact overall profile, enabling the structure to absorb collision energy effectively within limited space
Solution Approach 2:
The steel reinforcing frames are disposed within the hollow portions to maximize the use of available space. This nested arrangement allows the reinforcement to be contained within the limited side space while still providing sufficient collision energy absorption capacity through the high-strength steel material
3Weight of moving object
If hollow portions are provided in the side sill frame, then weight is reduced, but rigidity is decreased
Solution Approach 1:
The combination of aluminum extrusion with steel reinforcing frames creates a composite structure where the steel reinforcement compensates for the rigidity loss from hollow portions. The steel frames provide high stiffness and strength while the aluminum frame maintains lightweight properties, achieving both weight reduction and rigidity enhancement
Solution Approach 2:
The hollow portions are designed with specific cross-sectional geometries and are positioned strategically along the longitudinal direction. This dimensional optimization allows the hollow structure to maintain adequate rigidity by distributing stresses effectively while still providing weight reduction benefits
Data Source
AI summary
A side sill for a vehicle according to one embodiment of the present disclosure comprises: a side sill frame formed to have a hollow portion; a first reinforcing frame disposed in the hollow portion and attached to the side sill; a second reinforcing frame disposed in the hollow portion and attached to the first reinforcing frame and the side sill frame, wherein the first reinforcing frame and the second reinforcing frame are disposed in the hollow portion so as to form a closed cross-section in the hollow portion from a thickness-wise cross-section of the side sill frame.