Dual-Stage Bumper Energy Absorption for Pedestrian Safety
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Solution Overview
Problem
Current motor vehicle bumper systems fail to meet diverse global regulatory requirements with a single design, often prioritizing vehicle protection over pedestrian safety in low-impact collisions and are impractical due to styling constraints.
Innovation Solution
A dual-stage energy absorption bumper system with 'softer' energy-absorbing surfaces at the front and 'rigid' surfaces at the rear, varying wall thickness, and materials with different stiffness properties to manage energy absorption across different impact levels, allowing for efficient energy dissipation in both low- and high-impact collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single bumper system is designed to meet multiple global regulatory requirements, then adaptability is improved, but device complexity increases
Solution Approach 1:
The bumper system is divided into two distinct energy absorption stages with different structural configurations and material properties. The first stage uses softer materials with lower stiffness for low-impact collisions, while the second stage uses rigid materials with higher stiffness for high-impact collisions. This segmentation allows the single bumper system to meet multiple regional regulations by providing appropriate response characteristics for different impact scenarios.
Solution Approach 2:
Different portions of the bumper system are assigned different material properties and structural characteristics. The first stage elements have softer, more compliant properties optimized for pedestrian safety and low-speed impacts, while the second stage elements have harder, more rigid properties optimized for vehicle protection in high-speed collisions. This local differentiation enables the system to satisfy conflicting regional requirements simultaneously.
2Object-affected harmful factors
If softer energy absorbing surfaces are used at the front, then pedestrian safety in low-impact collisions is improved, but vehicle protection in high-impact collisions deteriorates
Solution Approach 1:
The energy absorption function is segmented into two sequential stages. The first stage uses softer materials that deform more easily to absorb low-impact energy, protecting pedestrians. The second stage uses rigid materials that maintain structural integrity for high-impact collisions, protecting the vehicle. Both stages are integrated into a single bumper assembly that progresses through the stages based on impact severity.
Solution Approach 2:
The bumper system dynamically transitions between different energy absorption mechanisms based on impact force magnitude. Under low impact forces, only the first stage with softer materials is activated. Under high impact forces, the second stage with rigid materials engages to provide additional protection. This dynamic response allows the system to optimize performance for the specific collision scenario.
3Strength
If rigid energy absorbing surfaces are used at the rear, then vehicle protection in high-impact collisions is improved, but pedestrian safety in low-impact collisions deteriorates
Solution Approach 1:
The bumper is segmented into front and rear portions with different mechanical properties. The front first stage uses softer materials for pedestrian safety, while the rear second stage uses rigid materials for vehicle protection. The segmentation creates a progressive energy absorption path that engages different stages based on impact force, allowing both safety requirements to be met simultaneously.
4Loss of energy
If a large area for energy absorption is designed in the bumper area, then energy absorption capability is improved, but styling requirements are compromised
Solution Approach 1:
Instead of uniformly increasing the bumper area, the invention applies different material properties and structural characteristics to specific local regions. The first stage elements are positioned in areas optimized for pedestrian interaction with softer materials, while the second stage elements are positioned for vehicle protection with rigid materials. This localized approach maintains aesthetic styling while providing sufficient energy absorption capacity through material differentiation rather than area expansion.
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 dual-stage system effectively absorbs energy in low-impact collisions, reducing force transfer to the object and providing enhanced protection in high-impact scenarios, while meeting various regulatory standards with a single bumper configuration.
Implementation Method 1
a first energy absorbing stage having at least one first stage element having a first impact resistance; and a second energy absorbing stage having a second impact resistance; wherein the first impact resistance is less than the second impact resistance
Implementation Method 2
a second energy absorbing stage having a second impact resistance; wherein the first impact resistance is less than the second impact resistance
Data Source
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AI summary
A motor vehicle bumper that has enhanced energy absorption characteristics and that includes one or more unique geometry configurations that extend "softer" energy absorbing surfaces forward in the system while nesting more "rigid" energy absorbing surfaces more rearward only to come into effect when higher energy impacts are observed. The dual energy absorption may be achieved using a number of configurations and/or methods or a combination of several. In one or more embodiments, the wall thickness of the material used in the component or components may be varied, materials having different stiffness properties may be used, and/or geometries of different depth and section stiffness may be alternated across the bumper system.