Multi-Layer Deformation Structure for Adaptive Pedestrian Protection
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Solution Overview
Problem
Existing motor vehicle bumper designs face a conflict between pedestrian protection and maintaining vehicle integrity at low speeds, requiring complex sensor systems and actuators to switch between stiff and soft states for energy absorption, which complicates the design and increases weight, affecting driving dynamics.
Innovation Solution
A deformation structure composed of multiple layers with complementary protrusions and depressions connected by deformable web elements, allowing automatic adjustment of stiffness based on collision impulse without the need for sensors or actuators, enabling the structure to absorb energy differently at varying collision speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a soft foam is arranged between the bumper cladding and the bumper cross member to protect pedestrians, then pedestrian protection is improved, but the vehicle structure becomes heavier and more complex
Solution Approach 1:
The patent applies parameter changes by using a deformation structure that automatically changes its stiffness parameter based on collision energy levels. At low collision energies (below 5-10 kJ), the structure remains stiff to maintain vehicle integrity. At high collision energies (above 10-20 kJ), the structure becomes soft through progressive deformation of layers to protect pedestrians. This eliminates the need for separate soft foam materials and active control systems.
Solution Approach 2:
The deformation structure is designed to automatically adjust its properties without external control systems. The multi-layer structure with progressive failure mechanisms self-regulates its stiffness based on the applied load, eliminating the need for sensors, actuators, and control electronics that would increase weight and complexity.
2Adaptability or versatility
If a sensor system and actuator are used to switch between stiff and soft states for energy absorption, then adaptability is improved, but the device complexity increases
Solution Approach 1:
The deformation structure automatically adapts to different collision scenarios through its progressive failure mechanism. The structure itself senses the collision energy level through the deformation state of its layers and responds by transitioning from a stiff to a soft state without requiring external sensors or actuators.
Solution Approach 2:
The patent replaces the mechanical system of sensors and actuators with a passive mechanical structure that uses progressive layer deformation and web element failure to achieve adaptive energy absorption. The adaptation is achieved through the inherent mechanical properties and geometric design of the multi-layer structure rather than active control systems.
3Loss of energy
If the deformation structure uses multiple layers with complementary protrusions and depressions, then energy absorption capability is improved, but the manufacturing complexity increases
Solution Approach 1:
The deformation structure is segmented into multiple layers with complementary protrusions and depressions that can be manufactured separately and then assembled. This segmentation allows each layer to be optimized for specific deformation modes and enables modular manufacturing, reducing overall complexity despite the sophisticated energy absorption mechanism.
Solution Approach 2:
The complementary protrusions and depressions create a nested arrangement where layers fit together in a telescoping manner during deformation. This nested geometry enables progressive energy absorption while the modular design allows for simplified manufacturing of individual layers that can be assembled through straightforward joining processes.
4Loss of energy
If a bumper arrangement with crash boxes and pivotable energy absorption elements is used, then collision energy absorption is improved, but the vehicle overhang increases and driving dynamics are adversely affected
Solution Approach 1:
The deformation structure uses thin-walled layered shells that can undergo large deformations within a compact volume. The progressive failure of web elements and layers provides extensive energy absorption pathways without requiring a long deformation distance, thus maintaining a compact front-end design that does not adversely affect driving dynamics.
Solution Approach 2:
The multi-layer structure functions as a composite system where different layers provide different mechanical functions. This composite approach maximizes energy absorption density within a compact volume, eliminating the need for extended crash boxes or pivotable elements that would increase vehicle overhang.
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 deformation structure automatically adjusts its stiffness in response to collision speed, providing effective pedestrian protection at higher speeds while minimizing damage and repair costs at low speeds, eliminating the need for sensor systems and simplifying production.
Implementation Method 1
The first layer and the second layer are connected to each other via deformable web elements
Implementation Method 2
deformation of the deformation structure in the deformation direction takes place at a relatively low force level
Implementation Method 3
the protrusions of the first layer enter into the depressions of the second layer and also the protrusions of the second layer enter into the depressions of the first layer, and therefore deformation of the deformation structure in the deformation direction takes place at a relatively low force level
Data Source
AI summary
A deformation structure has at least a first layer and a second layer, which are spaced apart from each other and displaceable relative to each other in the deformation direction or load direction. The first layer and the second layer have complementary protrusions and recesses, which are designed in such a way that the protrusions of the first layer can plunge into the recesses of the second layer and the protrusions of the second layer can plunge into the recesses of the first layer. The first layer and the second layer are connected to each other by deformable webs in such a way that, in the event of a high impulse in the deformation direction, the protrusions of the first layer plunge into the recesses of the second layer and the protrusions of the second layer plunge into the recesses of the first layer such that deformation of the deformation structure in the deformation direction occurs at a relatively low force level and, in the event of a low impulse in the deformation direction, the protrusions of the first layer hit the protrusions of the second layer such that further deformation of the deformation structure in the deformation direction occurs at a relatively high force level.