Sill Beam Uniform Deceleration Unit with Metallic Foam
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Solution Overview
Problem
Current vehicle safety systems, despite advancements, still fall short in effectively protecting occupants and electric vehicle batteries during side impacts without over-stiffening the vehicle structure or adding excessive mass, and they struggle to absorb significant impact energy in various crash scenarios.
Innovation Solution
A vehicle safety device comprising an outer skin casing with a low-density energy absorber and an inner skin stiffener with projections, designed to absorb crash energy, limit crash forces, and prevent deformation, which can be easily integrated into different vehicle architectures using a high-throughput manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional high-density energy absorbers are used, then impact energy absorption is improved, but vehicle mass increases excessively
Solution Approach 1:
The patent employs a porous foam core as the energy-absorbing material. The porous structure provides high energy absorption capacity through cell collapse mechanisms while maintaining low density. The foam core's cellular architecture allows it to deform progressively during impact, dissipating kinetic energy without requiring high material density, thus resolving the contradiction between energy absorption and mass.
Solution Approach 2:
The safety device uses a composite structure combining foam core material with skin layers and stiffeners. This composite construction integrates materials with different properties: the foam provides energy absorption, while the skins and stiffeners provide structural integrity. The composite design achieves effective energy dissipation without the excessive mass that would result from using solid high-strength materials throughout.
2Strength
If stiffeners are added to prevent deformation, then structural integrity is improved, but device complexity increases
Solution Approach 1:
The patent applies stiffeners locally at strategic positions rather than uniformly throughout the structure. The stiffeners are positioned to provide maximum structural support where needed during deformation, allowing the foam core to absorb energy while maintaining overall structural integrity. This localized approach achieves strength requirements without the complexity of a fully reinforced structure.
Solution Approach 2:
The safety device is segmented into distinct functional components: the foam core for energy absorption, skin layers for containment, and stiffeners for structural support. This segmentation allows each component to be optimized for its specific function and simplifies manufacturing and assembly compared to a monolithic complex structure.
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 solution effectively absorbs a substantial portion of crash kinetic energy, reducing the risk of damage to the vehicle and its occupants, while maintaining structural integrity and compatibility with various vehicle designs, including electric vehicles.
Implementation Method 1
the at least one low density material has a plurality of openings... effectively absorbs a substantial portion of crash kinetic energy
Implementation Method 2
the at least one inner skin stiffener includes a plurality of projections extending normal to the longitudinal axis of the outer skin casing... preventing deformation
Data Source
AI summary
Devices and methods for absorbing vehicle crash energy with a safety device are disclosed. The safety device may function as a uniform deceleration unit (UDU). In some embodiments, the UDUs described herein may include an assembly of an inner skin stiffener and an energy absorber, arranged inside of an outer skin casing. The inner skin stiffener may have a series of projections configured to engage with holes in the energy absorber which may help retain the two components fixed relative to one another. In some embodiments, the energy absorber may be formed of a low density material, such as a monolithic metallic foam material. The projections of the inner skin stiffener may be formed using a press forming method to simplify the manufacturability of the UDU and enhance the overall system throughput.