Composite Frangible Seat Brackets for Predictable Crash Energy Dissipation
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Solution Overview
Problem
Conventional energy dissipation solutions in passenger seats, such as metallic brackets, face issues with inconsistent load shearing due to metal composition and fatigue, leading to unacceptable Head Injury Criterion (HIC) and are weight-prohibitive, especially when considering weight reduction in vehicle design.
Innovation Solution
The use of composite materials, specifically carbon fiber reinforced polymers, for spreader and seat brackets, designed with frangible structures and energy-absorbing foam, allowing for predictable energy absorption and weight reduction, with specific layer orientations and thicknesses to control breakage patterns during crashes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic brackets are used for energy dissipation in passenger seats, then the structural strength is sufficient, but the weight becomes prohibitive and the shearing load becomes inconsistent due to metal composition and fatigue
Solution Approach 1:
The patent replaces traditional metallic brackets with composite material brackets that incorporate energy-absorbing foam cores. This composite construction maintains the required structural strength while significantly reducing the weight compared to solid metal brackets. The foam core provides energy absorption capabilities, eliminating the need for heavy metal construction.
Solution Approach 2:
The patent utilizes foam materials with controlled porosity as the core of the brackets. The porous foam structure absorbs impact energy through cell collapse and deformation, providing effective energy dissipation while maintaining low weight. The foam core is encapsulated within a composite shell to ensure structural integrity.
2Loss of energy
If metallic brackets with designed shear areas are used, then energy dissipation is achieved, but the shearing occurs at inconsistent loads due to metal composition and fatigue
Solution Approach 1:
The patent changes the material parameters from metallic to composite/foam materials with predictable deformation characteristics. The foam core is designed with specific density and cell structure parameters that ensure consistent energy absorption and predictable failure loads. This eliminates the variability associated with metal composition and fatigue.
Solution Approach 2:
The patent pre-configures the foam core with predetermined density gradients and structural features that guide the deformation and failure process. The frangible sections are designed in advance with specific geometric features that ensure they fail at consistent, predictable loads during impact events.
3Weight of moving object
If composite materials are used for brackets, then weight is reduced and energy absorption is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent combines the foam core and composite shell into an integrated bracket structure through co-curing or adhesive bonding processes. This merging of components simplifies the overall manufacturing process compared to assembling multiple separate parts, while still achieving the weight reduction and energy absorption benefits of composite materials.
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 solution reduces the impact energy transferred to occupants, decelerates them during crashes, and minimizes head trauma by allowing the seatback to pivot forward, thereby improving safety metrics like HIC while reducing overall weight.
Implementation Method 1
The frangible structure can be configured to break at or near the shear area in response to a force applied to a seatback
Implementation Method 2
designed with frangible structures and energy-absorbing foam, allowing for predictable energy absorption
Data Source
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AI summary
Seat assemblies including seat brackets and spreader brackets are described. A seat bracket can include an upper portion, a lower portion, and a frangible portion. The frangible portion can be formed from composite material and include a particular layer orientation. A spreader bracket can include a first component configured to couple with a second component to form a coupled structure. A structural fill material can be disposed within the coupled structure. The first component and the second component can be formed from composite material.