Deformable Cell Seatback Energy Absorber
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Solution Overview
Problem
During vehicle impacts, existing seat designs fail to effectively manage the kinematic motion of seat components relative to bulkheads, leading to uncontrolled deformation and potential injury risks due to inadequate energy absorption and dissipation.
Innovation Solution
Incorporating deformable cells between the seatback frame and rear trim cover, which extend from the frame to the rear trim cover, featuring a contraction zone that deforms under impact forces, absorbing and dissipating kinetic energy through a vent system and fill material, thereby controlling the seat's motion and reducing deceleration rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing seat designs are used during vehicle impacts, then the seat structure remains simple and rigid, but the kinematic motion of seat components relative to bulkheads cannot be effectively managed, leading to uncontrolled deformation and potential injury risks
Solution Approach 1:
The deformable cell is divided into multiple cells arranged in an array between the seatback frame and bulkhead. Each cell independently absorbs energy through deformation, providing distributed protection while maintaining a manageable overall structure. The segmentation allows the system to handle complex impact scenarios through multiple simple, identical units.
Solution Approach 2:
The deformable cell changes its physical parameters during impact by transitioning from a rigid pre-impact state to a deformed post-impact state. The cell's contraction ratio and material properties are specifically designed to control the deformation characteristics, allowing energy absorption while managing the complexity of the deformation process through predictable parameter changes.
2Loss of energy
If a rigid seatback structure is used, then manufacturing and assembly are simpler, but energy absorption and dissipation during impact are inadequate, causing uncontrolled deformation
Solution Approach 1:
The deformable cell is pre-configured with a specific geometry including a contraction ratio less than 0.5, creating a built-in energy absorption mechanism before impact occurs. This beforehand cushioning allows the cell to deform in a controlled manner during impact, absorbing energy that would otherwise be transmitted to the occupant, while the pre-designed geometry simplifies the manufacturing process.
Solution Approach 2:
The deformable cell utilizes a porous or cellular material structure that enables controlled deformation and energy absorption. The porous architecture allows the material to collapse in a predictable manner during impact, dissipating energy through cell wall buckling and fracture, while the regular porous pattern simplifies manufacturing through consistent molding or extrusion processes.
3Loss of energy
If the deformable cell has a high contraction ratio, then the structure remains stronger, but energy absorption capacity is reduced
Solution Approach 1:
The contraction ratio is specifically designed to be less than 0.5, creating an optimal balance between strength and energy absorption. This parameter change allows the cell to deform sufficiently to absorb kinetic energy while maintaining enough structural integrity to control the deformation process. The specific contraction ratio parameter enables predictable energy dissipation characteristics.
Solution Approach 2:
The deformable cell transitions from a static strong structure to a dynamic energy-absorbing element during impact. The cell's structural properties are designed to change under load, with the contraction ratio enabling a dynamic response that optimizes both strength during deformation and energy absorption capacity. The dynamic behavior allows the cell to adapt its effective strength 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
The deformable cell assembly effectively absorbs and dissipates impact energy, reducing the severity of seatback contact with bulkheads, thereby enhancing occupant safety by controlling kinematic motion and distributing forces across multiple cells.
Implementation Method 1
The deformable cell has a contraction between the first end and the second end... featuring a contraction zone that deforms under impact forces, absorbing and dissipating kinetic energy
Implementation Method 2
The deformable cell may include a vent in communication with the interior chamber, the vent being releasable in response to pressure in the interior chamber exceeding a threshold
Data Source
AI summary
An assembly includes a seatback defining an occupant-seating area. The seatback has a frame and a rear trim cover. The frame is between the occupant-seating area and the rear trim cover. The assembly includes a seat bottom extending from the seatback below the occupant-seating area. The assembly includes a deformable cell between the frame and the rear trim cover. The deformable cell extends from a first end proximate the frame to a second end proximate the rear trim cover. The deformable cell has a contraction between the first end and the second end.