Motor Vehicle Bumper Layout for Small-Overlap Energy Absorption
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Solution Overview
Problem
Existing bumper arrangements for motor vehicles face challenges in efficiently absorbing energy during accidents, especially when subjected to one-sided or unfavorable loads, while also meeting requirements for pedestrian protection and minimizing weight and installation space usage.
Innovation Solution
The bumper arrangement incorporates a second deformation element in the form of a strandpress profile oriented along the vehicle's high axis, which is strategically positioned externally relative to the first deformation elements (crash boxes) to enhance energy absorption and crash performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional bumper arrangement with only crash boxes is used, then the structure is simple and weight is reduced, but the energy absorption capacity under one-sided or unfavorable loads is insufficient
Solution Approach 1:
The bumper arrangement is divided into multiple functional segments: first deformation elements (crash boxes) for central impact absorption and second deformation elements (extruded profiles) for lateral and one-sided impact absorption. This segmentation allows each component to specialize in specific load scenarios, improving overall energy absorption capacity while maintaining a modular structure that doesn't excessively increase complexity.
Solution Approach 2:
Different deformation elements are strategically positioned at specific locations: crash boxes are positioned centrally for primary impact absorption, while extruded profiles are positioned laterally at the outer end sections for handling one-sided and unfavorable loads. This local optimization ensures that each region of the bumper has the appropriate deformation capacity for the expected load patterns, maximizing energy absorption efficiency.
2Strength
If additional deformation elements are added to improve crash performance, then energy absorption capacity increases, but weight and installation space increase
Solution Approach 1:
The second deformation elements use extruded profiles with optimized geometric parameters and material properties tailored for lateral and one-sided impact scenarios. By carefully selecting the profile geometry, material grade, and dimensions, the energy absorption capacity is enhanced while minimizing the added weight. The extruded profile design allows for efficient material distribution that maximizes strength-to-weight ratio.
Solution Approach 2:
The bumper arrangement combines different deformation elements (crash boxes and extruded profiles) that may utilize different material compositions and structural characteristics. This composite approach allows each material to be optimized for its specific function, achieving superior overall crash performance while managing weight through selective material placement rather than uniformly increasing mass throughout the entire bumper assembly.
3Strength
If the bumper arrangement is designed for optimal central impact absorption, then crash box positioning is optimized, but performance under unfavorable load conditions (small overlap) deteriorates
Solution Approach 1:
The bumper arrangement is designed with multi-functional deformation elements that can handle multiple impact scenarios. The first deformation elements (crash boxes) primarily handle central impacts, while the second deformation elements (extruded profiles) positioned at the outer end sections provide additional capacity for one-sided and unfavorable load conditions. This universal design ensures reliable performance across various collision types without compromising central impact optimization.
Solution Approach 2:
The solution adds a lateral dimension to the traditional central impact-focused design by positioning second deformation elements at the outer end sections of the cross member. This dimensional expansion from purely central to including lateral deformation capacity allows the bumper to effectively handle both central crashes and unfavorable small-overlap conditions, improving reliability across different impact geometries.
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 improves the energy absorption capacity and crash behavior of the bumper arrangement, even under unfavorable load conditions, while maintaining a lightweight design and optimizing the use of available installation space.
Implementation Method 1
The cross member serves to transfer the energy resulting from an impact into the crash boxes, where the impact energy is converted into deformation work
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A bumper assembly 1 for a motor vehicle comprises a cross member 2 and first deformation elements in the form of crash boxes 3. A second deformation element is provided laterally adjacent to at least one first deformation element. The second deformation element is an extruded profile 8, the extrusion direction of which is oriented along the z-axis (vehicle vertical axis) of the motor vehicle. The second deformation element has an inner side wall and an outer side wall, which are connected to each other via at least one transverse web.