Front Side Frame with Alternating Rigidity for Collision Energy Absorption
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Solution Overview
Problem
In vehicle frontal collisions, the energy absorption efficiency of front side frames is compromised when the midway portion is crushed first, leading to uneven deformation and reduced energy absorption capacity due to the length of the front side frame.
Innovation Solution
A front vehicle-body structure with alternating rigidity differences between the front and rear portions of the front side frames, where the rear portion has higher rigidity than the front, allowing for smooth compressive deformation from the front side portion across the entire longitudinal direction through recessed bead portions and low rigidity portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the front side frame is made longer to increase energy absorption capacity, then the energy absorption amount increases, but the midway portion is crushed first causing uneven deformation and reducing energy absorption efficiency
Solution Approach 1:
The front side frame is designed with non-uniform rigidity distribution along its length. The rigidity is differentiated into multiple regions (first, second, and third rigidity regions) from front to rear, with each region having distinct rigidity characteristics. This local quality variation ensures that the frame deforms uniformly during collision by controlling the deformation progression through strategically placed rigidity zones, preventing premature crushing at the midway portion while maintaining adequate energy absorption capacity.
2Strength
If the front side frame is designed with high rigidity throughout to maintain structural integrity, then the structural strength increases, but the compressive deformation cannot start smoothly from the front portion
Solution Approach 1:
The frame employs localized rigidity variation where the front portion has lower rigidity than the rear portion. Specifically, the first rigidity region (front) has lower rigidity to enable smooth compressive deformation initiation, while the second and third rigidity regions (rear) have progressively higher rigidity to maintain structural integrity. This gradient rigidity distribution allows the frame to deform smoothly at the front while preserving overall strength.
Solution Approach 2:
The front side frame is segmented into multiple rigidity regions along its longitudinal axis. The first rigidity region (front portion) is designed with lower rigidity for controlled deformation, while the second and third rigidity regions (rear portions) have higher rigidity for structural support. This segmentation allows different parts of the frame to perform different functions - the front region absorbs energy through deformation while the rear regions maintain structural integrity.
3Ease of operation
If the front side frame is designed with low rigidity at the front portion to enable smooth deformation, then the compressive deformation starts smoothly, but the overall structural strength may be reduced
Solution Approach 1:
The frame employs localized rigidity variation where the front portion has lower rigidity than the rear portion. Specifically, the first rigidity region (front) has lower rigidity to enable smooth compressive deformation initiation, while the second and third rigidity regions (rear) have progressively higher rigidity to maintain structural integrity. This local quality variation ensures that the frame deforms uniformly during collision by controlling the deformation progression through strategically placed rigidity zones, preventing premature crushing at the midway portion while maintaining adequate energy absorption capacity.
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
This configuration ensures reliable and smooth compressive deformation of the front side frame during a collision, enhancing energy absorption efficiency by initiating deformation from the low rigidity front portion and maintaining structural integrity through the rear high rigidity portion.
Implementation Method 1
a front portion of the front side frame is compressively deformed (so-called axial compressive deformation) and crushed in the front-rear direction
Implementation Method 2
the axial compressive deformation can absorb a larger amount of collision energy with the same stroke
Implementation Method 3
a rear portion of the front side frame is bent (so-called lateral breakage deformation) so as to protrude to the vehicle-width-direction outer side
Data Source
Figure 1
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AI summary
A front vehicle-body structure of a vehicle includes a pair of left and right front side frames extending in a vehicle front-rear direction. Each of the front side frames is formed such that a rear portion has a higher rigidity than a front portion. Rigidity differences are alternately formed in the vehicle front-rear direction in each of regions of the front portion and the rear portion.