Pedestrian Protection Bumper Deformation Element
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Solution Overview
Problem
Existing pedestrian protection systems for motor vehicles face contradictory requirements at different speeds, necessitating a solution that can switch between rigidities independently of sensor systems or actuators to effectively manage collision energy absorption while minimizing vehicle length and weight.
Innovation Solution
A pedestrian protection device featuring a crossmember with a deformation element having a bending limb that latches into place upon collision, allowing the system to adjust stiffness based on collision impulse without requiring a sensor or actuator system, thereby stiffening during higher impact forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a long vehicle overhang is used to resolve contradictory requirements for pedestrian protection and damage minimization, then pedestrian protection is improved, but vehicle length and weight increase
Solution Approach 1:
The bumper crossmember is designed with dynamic rigidity characteristics that allow it to deform in an energy-absorbing manner during collisions. The crossmember includes deformation elements that can bend and absorb impact energy, transitioning from a rigid structure to a controlled deformation structure based on impact force, thereby providing pedestrian protection without requiring a long vehicle overhang
Solution Approach 2:
The crossmember is designed with varying wall thicknesses and structural parameters along its length. The wall thickness is reduced in specific regions to create controlled deformation zones, while other regions maintain higher strength. This parameter variation allows the crossmember to provide both pedestrian protection and structural integrity without increasing overall vehicle length
2Reliability
If a stiff crash structure with high collision energy absorption capability is used, then occupant protection is improved, but damage to surrounding components increases
Solution Approach 1:
The crossmember is divided into multiple segments with different structural characteristics: a first region with higher wall thickness for structural integrity, a second region with reduced wall thickness for energy absorption, and a third region with intermediate properties. This segmentation allows different parts of the crossmember to perform different functions - protecting occupants while minimizing damage to surrounding components
Solution Approach 2:
The crossmember features local variations in wall thickness and structural properties. Specifically, the wall thickness is reduced in the second region to create a deformation zone that absorbs collision energy, while the first and third regions maintain higher strength to protect occupants and support vehicle structure, respectively
3Reliability
If a deformable foam is used for pedestrian protection, then pedestrian protection is improved within certain speed range, but collision energy absorption capability decreases
Solution Approach 1:
The crossmember combines materials with different properties - primarily metallic materials with varying wall thicknesses to create a composite structure that provides both pedestrian protection and collision energy absorption. The deformation elements are designed to undergo controlled plastic deformation, absorbing kinetic energy from both pedestrian collisions and higher-speed impacts
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 device effectively manages collision energy absorption by transitioning between soft and stiff states based on collision force, ensuring pedestrian protection across varying speed ranges while maintaining vehicle dynamics and minimizing damage to surrounding components.
Implementation Method 1
The end of the bending limb is designed to be displaceable along the surface as a result of the collision, wherein the surface has a latching device with which the end of the bending limb is in particular latchable
Implementation Method 2
a deformation element, which is arranged in front of the crossmember. The deformation element has a bending limb, the end of which lies against a surface or, in the event of a collision, in particular a head-on collision, of the motor vehicle comes to bear against the surface
Data Source
AI summary
A pedestrian protection device for a motor vehicle, in particular for a front part of the motor vehicle, includes a bumper crossbeam and a deformation element arranged in front of the bumper crossbeam. The deformation element has a bending section, the end of which is in contact with a surface or which comes into contact with the surface in the event of a collision, in particular a front collision of the motor vehicle. The end of the bending section is designed such that it can move along the surface as a result of the collision, wherein the surface has an engaging device with which the end of the bending section can be, in particular, engaged.