Variable-Stiffness Deformation Structure for Pedestrian Impact Protection
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Solution Overview
Problem
Existing motor vehicle bumper structures face a conflict in achieving pedestrian protection at low speeds without damaging the vehicle, while also requiring minimal damage at higher speeds, leading to increased weight and adverse driving dynamics.
Innovation Solution
A deformation structure with complementary protrusions and depressions on two layers connected via a deformation control device, allowing automatic adjustment of stiffness based on collision impulse, eliminating the need for sensor systems or actuators to switch between soft and stiff states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a soft foam is arranged between the bumper cladding and the bumper crossmember for pedestrian protection, then pedestrian protection is improved, but the vehicle structure becomes heavier and driving dynamics are adversely influenced
Solution Approach 1:
The deformation structure changes its stiffness parameter automatically based on collision impulse magnitude. At low impulses (pedestrian collisions), the structure deforms easily to absorb energy and protect pedestrians. At high impulses (vehicle-to-vehicle collisions), the structure becomes stiff to maintain structural integrity and protect the radiator and other components.
Solution Approach 2:
The deformation structure transitions from a static foam material to a dynamic system that adapts its mechanical properties in real-time based on the collision characteristics. The complementary protrusions and depressions enable the structure to switch between soft and stiff states during the collision event itself, without requiring active control systems.
2Object-affected harmful factors
If a long vehicle overhang is provided to accommodate both pedestrian protection and collision energy absorption, then both pedestrian protection and collision damage reduction are improved, but the vehicle weight increases and driving dynamics are adversely influenced
Solution Approach 1:
The deformation structure provides variable stiffness that adapts to different collision scenarios, eliminating the need for a permanently long overhang structure. The same compact structure can provide both soft deformation for pedestrian protection and stiff support for protecting the radiator and other components, depending on the collision impulse magnitude.
3Object-affected harmful factors
If a sensor system and actuator are used to switch between soft and stiff states for pedestrian protection, then pedestrian protection and collision damage reduction are improved, but the device complexity increases
Solution Approach 1:
The deformation structure automatically responds to collision impulses without requiring external sensors or actuators. The complementary protrusions and depressions are designed to naturally engage or disengage based on the magnitude of the applied force, enabling the structure to self-regulate its stiffness and deformation behavior.
Solution Approach 2:
The invention removes the complex sensor system and actuator mechanisms from the design while retaining the essential function of switching between soft and stiff states. The switching function is achieved purely through the mechanical design of the complementary protrusions and depressions, eliminating the need for electronic control systems.
4Object-affected harmful factors
If the deformation structure is designed to deform at low force for pedestrian protection, then pedestrian protection is improved, but the ability to protect the vehicle structure at higher speeds deteriorates
Solution Approach 1:
The deformation structure changes its force-deformation characteristics based on the collision impulse. At low forces, the complementary protrusions and depressions allow easy engagement and deformation to protect pedestrians. At high forces, the structure transitions to a stiff state that resists deformation and protects the radiator and other vehicle components.
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 reliably deforms at higher forces at low impulses, transmitting greater forces, and at lower forces at high impulses, effectively managing collision energy absorption without additional systems, reducing repair costs and maintaining vehicle integrity across speed ranges.
Implementation Method 1
The control webs (71) are configured in each case between two oppositely situated fastening webs (73) and display, depending on a collision impulse, a hinge action in a certain direction
Implementation Method 2
adjacent layers (3, 5) undergo a pivoting movement in relation to one another
Implementation Method 3
the protrusions of the first layer and the depressions of the second layer and also the protrusions of the second layer and the depressions of the first layer can enter into one another
Implementation Method 4
a deformation of the deformation structure in the deformation direction takes place at a relatively low level of force
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 are mounted to be movable 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 such that the protrusions of the first layer can dip into the recesses of the second layer and vice versa. The first layer and the second layer are connected to each other by deformable connecting pieces such that, in the event of a high impulse in the deformation direction, the protrusions of the first layer dip into the recesses of the second layer and the protrusions of the second layer dip into the recesses of the first layer such that the deformation structure is deformed in the deformation direction at a relatively low level of force 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 the deformation structure is deformed further in the deformation direction at a relatively high level of force. The deformation control device is formed or produced separately from the first and the second layer and is removably or non-removably connected to the first layer and the second layer.