Bumper Cross Beam Geometry for Pole Impact Energy Absorption
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Solution Overview
Problem
Bumper cross-carriers need to balance rigidity for impact resistance with producibility and energy absorption, particularly in center pole tests, while avoiding deformation that could compromise protection for vehicle components like side walls and batteries.
Innovation Solution
A bumper arrangement with a cross-carrier featuring a hollow profiled front and rear wall, where the front wall is significantly shorter than the rear wall, forming a pull-tape composite that absorbs impact without tearing, and enhanced by a seec extending along the vehicle's longitudinal direction, which expands vertically and presses flat during deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the cross member is designed to be as rigid as possible, then it provides sufficient support and resistance to deformation during pole tests, but it cannot absorb energy through deformation and increases production cost
Solution Approach 1:
The patent applies parameter changes by modifying the development length relationship between front and rear walls from equal to unequal (front wall 5-15% shorter), transforming the cross member from a purely rigid structure to one that can control deformation patterns to absorb energy while maintaining strength
Solution Approach 2:
The patent creates a composite structural system where the front and rear walls with different development lengths work together to form a tension band composite, combining rigid support with controlled deformation energy absorption capabilities
2Ease of manufacture
If the front and rear walls have equal development length, then the structure is symmetric and easier to manufacture, but the cross member may break under strong intrusion forces during pole tests
Solution Approach 1:
The patent deliberately introduces asymmetry by making the front wall development length 5-15% shorter than the rear wall, which prevents tearing under strong intrusion forces while maintaining manufacturability through a controlled asymmetric design
Solution Approach 2:
The asymmetric development length is designed in advance to create a tension band effect that prevents tearing during pole tests, preparing the structure to handle extreme forces before they occur
3Loss of energy
If the cross member deforms to absorb energy, then it protects components behind it, but it may compromise the rigidity needed for adequate support during impact
Solution Approach 1:
The patent changes the structural parameters by creating unequal development lengths (front wall 5-15% shorter than rear wall), enabling the cross member to deform in a controlled manner that absorbs crash energy while maintaining adequate support rigidity through the tension band composite effect
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 solution provides sufficient rigidity during impacts, reducing the risk of deformation and maintaining structural integrity by distributing crash energy effectively, thus protecting critical vehicle components.
Implementation Method 1
the crossbeam conforms to the cross-sectional contour of the pole. In this process, the front and rear walls move towards each other. The front and rear walls of the crossbeam then each form a tension band
Implementation Method 2
crash energy is converted into deformation work
Data Source
Figure 1
Figure 2~3
Figure 4a~4d
AI summary
The present invention relates to a bumper arrangement (1) which is coupled to a motor vehicle via crash boxes (3), comprising a cross member (2) which has a profiled front wall (5) and a profiled rear wall (6) in cross-section, characterized in that the development length of the front wall (5) in the motor vehicle vertical direction (Z) is less than 20%, in particular less than 15% and preferably less than 10% smaller, in relation to the development length of the rear wall (6), but at least both development lengths are equal, preferably the development length of the front wall (5) is at least more than 1% smaller than the development length of the rear wall (6).