Bumper Cross Beam Geometry for RCAR and Pendulum Test Compliance
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Solution Overview
Problem
Conventional bumper cross members face challenges in meeting conflicting requirements of the RCAR barrier test and pendulum impact test, risking damage to the bending beam and requiring excessive installation space, while also struggling with the less favorable geometric conditions for plastic materials.
Innovation Solution
The bumper cross member's geometry is optimized by setting back the camber of the bending beam to reduce the intrusion path and early activate crash boxes in the RCAR barrier test, and incorporating humps to absorb pendulum impact forces, thereby reducing the risk of bending beam damage and minimizing installation space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bending beam is given sufficient camber for the RCAR barrier test, then the crash boxes can be activated early to protect components, but the bending beam may break during deflection and requires large installation space
Solution Approach 1:
The bumper cross member is segmented into distinct functional zones: the bending beam with reduced camber for structural integrity, and separately positioned crash boxes for energy absorption. This segmentation allows each component to perform its specific function optimally without compromising the other.
Solution Approach 2:
The crash boxes are positioned to be activated early in the impact sequence, before the bending beam undergoes significant deflection. This preliminary activation of the crash boxes absorbs impact energy upfront, preventing excessive bending beam deflection and potential breakage.
2Reliability
If the bending beam is given sufficient camber for the RCAR barrier test, then the crash boxes can be activated early, but a relatively large installation space is required
Solution Approach 1:
By segmenting the bumper design and positioning crash boxes separately from the bending beam, the overall installation space is optimized. The crash boxes are placed at locations that minimize the required deflection space while ensuring early activation.
Solution Approach 2:
The crash boxes are positioned to activate preliminarily in the impact sequence, absorbing energy before the bending beam deflects significantly. This reduces the required deflection space and overall installation volume while maintaining reliable crash box activation.
3Use of energy by moving object
If the bending beam geometry is optimized for the RCAR barrier test, then energy absorption is improved, but the pendulum impact test requirements may not be met
Solution Approach 1:
Different local geometries are applied to different parts of the bumper cross member. The bending beam has reduced camber for RCAR test optimization, while humps are added in specific areas to maintain stiffness and meet pendulum test requirements. Each local feature is optimized for its specific functional requirement.
Solution Approach 2:
The bumper design is segmented into regions with different geometric characteristics: the central bending beam area with reduced camber for energy absorption, and localized humps for maintaining stiffness. This allows simultaneous compliance with both test requirements through spatial differentiation.
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 design enhances energy absorption and protection of vehicle components, while significantly reducing installation space requirements without compromising test compliance, particularly benefiting plastic materials by optimizing strength and flexibility.
Implementation Method 1
a non-destructive deflection of the bending beam is desired, which enables the crash boxes to be activated
Implementation Method 2
the crash boxes are activated and thus prevents damage to the vehicle structure behind it
Implementation Method 3
incorporating humps to absorb pendulum impact forces
Data Source
Figure 1~3
AI summary
The present invention relates to a bumper cross beam (1) having a bumper bracket (2) and two side crash boxes (3) with a geometric structure which is adjusted to the dimensions of testing equipment.