Dilatant Impact Absorber for Early Floor G-Force Control
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Solution Overview
Problem
In automobile front end structures, high-speed collisions result in large passenger impacts due to insufficient initial deceleration of the vehicle body floor portion, making it difficult to absorb energy effectively before the crash box reaches maximum deformation, thus increasing passenger deceleration and potential damage.
Innovation Solution
Incorporating a dilatant impact absorbing body made of D3O™ between the front side member and the front bumper reinforcement, allowing for axial compressive deformation of the crash box, which absorbs energy and hardens when the deformation exceeds a set value, increasing the vehicle body floor deceleration (G-force) before the crash box reaches maximum deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If only a crash box is used for energy absorption, then the structure is simple and repairable, but the floor G does not increase sharply until the crash box is completely crushed, causing large passenger deceleration in high-speed collisions
Solution Approach 1:
The impact absorbing structure is segmented into two distinct components: a crash box for initial energy absorption and a dilatant impact absorbing body for secondary energy absorption. This segmentation allows the floor G to increase sharply before the crash box reaches maximum deformation, reducing passenger deceleration while maintaining overall structural simplicity and repairability.
Solution Approach 2:
The dilatant impact absorbing body acts as an intermediary element between the crash box and the front side member. It mediates the energy absorption process by providing additional resistance before the crash box is fully crushed, thereby controlling the timing of floor G increase without complicating the overall structure.
2Strength
If the crash box is designed to absorb all impact energy, then the structure can handle high-speed collisions, but the ability to withstand damage and repairability is reduced
Solution Approach 1:
The energy absorption function is segmented between two components with different properties: the crash box maintains good repairability while the dilatant impact absorbing body provides enhanced collision resistance. This segmentation allows the system to handle high-speed collisions effectively while preserving the ease of repair for the most critical structural elements.
Solution Approach 2:
The impact absorbing structure uses composite design combining a metal crash box with a polymer-based dilatant impact absorbing body made of D3O™ material. This composite approach leverages the strengths of both materials: the crash box provides structural integrity and repairability, while the dilatant material provides superior energy absorption for high-speed collisions.
3Ease of operation
If the dilatant impact absorbing body is positioned to engage early, then floor G increases sharply, but the crash box cannot achieve maximum deformation for energy absorption
Solution Approach 1:
The dilatant impact absorbing body is positioned and dimensioned to engage in preliminary action before the crash box reaches maximum deformation. This preliminary engagement causes floor G to increase sharply, controlling deceleration, while leaving sufficient space for the crash box to achieve its full energy absorption potential.
Solution Approach 2:
The system dynamically adapts to collision severity through the progressive engagement of the dilatant impact absorbing body. In minor collisions, only the crash box deforms; in high-speed collisions, the dilatant body engages after the crash box reaches a certain deformation level, optimizing both deceleration control and energy absorption based on the impact conditions.
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 design enhances the vehicle's ability to withstand damage and improve repairability by suddenly increasing floor G-force during high-speed collisions, reducing passenger deceleration and energy absorption by the crash box, while maintaining effective energy absorption during minor collisions.
Implementation Method 1
a dilatant impact absorbing body that is formed of D3OTM and is disposed between the front end of the front side member and the front bumper reinforcement
Implementation Method 2
a space for permitting axial compressive deformation of the crash box at a time of a front collision of the automobile
Data Source
AI summary
In an automobile front portion structure, a dilatant impact absorbing body that is formed from a material having dilatant characteristics is accommodated at an inner side of a crash box and is fixed to a front end surface of a front side member. A length dimension in a vehicle longitudinal direction of this dilatant impact absorbing body is set such that, when an axial compressive deformation amount of the crash box becomes greater than or equal to a set value that is smaller than a maximum value of the axial compressive deformation amount, the dilatant impact absorbing body receives compressive load between the front side member and a front bumper reinforcement.