Double-Acting Crush Lobes for Compact Energy Absorption
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Solution Overview
Problem
Existing energy absorber constructions in vehicles face challenges in providing optimal crush resistance and impact stroke length while minimizing space and weight, and require flexibility to adapt to different crash scenarios and pedestrian safety needs, with a need for customizable and cost-effective designs that do not compromise on passenger or pedestrian safety.
Innovation Solution
The development of an energy absorber with expandable polymeric panel members featuring aligned crush lobes that move in opposite directions, utilizing an inflator to expand and absorb energy, and incorporating offset ring sections that roll and collapse to absorb impact, allowing for customizable energy absorption profiles and compact storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the impact stroke length is increased to improve energy absorption, then energy absorption capability is improved, but passenger space in the vehicle compartment is reduced
Solution Approach 1:
The crush lobes are nested within each other in a telescoping arrangement, allowing the energy absorber to achieve a long impact stroke while maintaining a compact retracted profile that minimizes space requirements in the vehicle compartment
Solution Approach 2:
The energy absorber transitions from a static compact structure to a dynamic telescoping structure during deployment, extending the crush lobes in opposite directions to provide increased stroke length only when needed for energy absorption
2Force
If crush resistance is increased to improve energy absorption, then energy absorption capability is improved, but load spikes increase which can cause injury
Solution Approach 1:
The crush lobes are designed with varying wall thicknesses and geometric configurations in different sections, allowing each local region to contribute differently to the overall crush resistance profile, thereby smoothing out load spikes while maintaining effective energy absorption
Solution Approach 2:
The dual-acting crush lobes dynamically adjust the crush resistance during deployment, providing progressive resistance that adapts to the impact force rather than maintaining a fixed high resistance that would create harmful load spikes
3Adaptability or versatility
If multiple components are used to provide customized energy absorption for different crash scenarios, then adaptability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The energy absorber is designed as a universal component that can provide customized energy absorption characteristics for different crash scenarios through variations in the geometric parameters of the crush lobes, eliminating the need for multiple specialized components
Solution Approach 2:
Customization is achieved by changing the geometric parameters of the crush lobes such as wall thickness, curvature, and segmentation patterns, rather than using different components, thereby reducing device complexity while maintaining adaptability
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 solution provides a flexible, space-efficient, and cost-effective energy absorption system that can adapt to various crash scenarios, enhancing both passenger and pedestrian safety by offering a longer crush stroke and reduced load spikes, while maintaining a compact form factor and functioning across different temperatures.
Implementation Method 1
an inflator positioned within the sealed cavity for expanding the crush lobes
Implementation Method 2
each crush lobe being movable between a collapsed position where the crush lobes are collapsed toward each other and an expanded position where the crush lobes are expanded in generally opposite directions
Implementation Method 3
Energy absorption occurs in components that provide a combination of optimal crush resistance and impact stroke
Data Source
AI summary
An energy absorber includes opposing aligned crush lobes expandable in opposite directions, and when expanded, potentially collapse with different energy-absorbing rates and stroke distances. The energy absorber forms a subassembly design that is adaptable and easily modified for predetermined energy absorption crush curves and specific energy-absorbing circumstances, such that it can be used inside a vehicle passenger compartment or outside a vehicle in different locations, such as for a knee bolster on the instrument panel, or on a door inner panel, or on an under-knee seat component, or on a headliner or A-pillar cover, or hood-lifter for pedestrian safety. One version of the energy absorber includes formed sheets bonded along a perimeter to define two cavities and an inflator-holding pocket connected to the cavities by integrally-formed tunnels.