Segmented Viscoelastic Foam Helmet Subliner for Angular Acceleration
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Solution Overview
Problem
Current helmets do not adequately reduce head angular acceleration during impacts, which contributes to concussions and long-term injuries like chronic traumatic encephalopathy (CTE), especially in scenarios involving both horizontal and downward forces.
Innovation Solution
The helmet features a subliner system with energy-absorbing viscoelastic foam pads, including a third type of subliner element with a flat horizontal surface that remains tangent to the head, and radially partitioned segments with nano tape for enhanced sliding engagement, to minimize horizontal forces and angular acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the subliner element uses a flat lower surface to slide by the wearer's head during horizontal impact, then angular acceleration is reduced, but the element cannot effectively absorb downward impact forces
Solution Approach 1:
The subliner element is divided into multiple independent foam columns arranged radially. Each column can deform independently, allowing the structure to adapt to complex impact directions. The segmented design enables both sliding motion for horizontal impacts and vertical compression for downward forces, resolving the contradiction between reducing angular acceleration and maintaining protection reliability.
Solution Approach 2:
The foam columns are designed to be dynamically responsive, changing their mechanical behavior based on impact direction and magnitude. During horizontal impact, the columns allow sliding motion; during downward impact, they compress vertically. This dynamic adaptation enables the subliner to effectively reduce angular acceleration while maintaining protection effectiveness under combined horizontal and downward forces.
2Ease of operation
If the subliner element conforms to the curved head surface, then comfort and fit are improved, but horizontal sliding is prevented causing increased angular acceleration
Solution Approach 1:
Different regions of the subliner element have different geometric properties. The foam columns have flat lateral surfaces that enable sliding, while the overall arrangement conforms to the head's curvature through radial positioning. This local differentiation allows the subliner to provide comfort and fit through conformance while maintaining sliding capability to reduce angular acceleration.
3Ease of manufacture
If a single foam pad design is used, then manufacturing is simplified, but performance under different impact directions is compromised
Solution Approach 1:
Rather than creating a single complex foam pad design to handle all impact directions, the invention segments the element into multiple identical or similar foam columns. This segmentation maintains manufacturing simplicity while achieving versatility in handling different impact directions, as each column performs the same function but collectively they cover all directions.
Solution Approach 2:
The invention changes the geometric parameters of the foam columns (radial arrangement, spacing, height) to optimize performance across different impact directions while maintaining a consistent manufacturing process for each individual column. This parameter optimization achieves adaptability without sacrificing manufacturing ease.
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 subliner system significantly reduces the level of head angular acceleration during impacts, providing improved protection against concussions and potentially mitigating the risk of CTE by distributing and absorbing forces effectively.
Implementation Method 1
The first foam pad is constructed of an energy absorbing viscoelastic foam material
Implementation Method 2
an energy absorbing viscoelastic foam material capable of exhibiting a compressive stress of at least 50 psi for a dynamic compression of 50%
Implementation Method 3
The independent segments are nested with respect to each other such that the nested segments have side surfaces in slidable direct contacting engagement with side surfaces of adjacent nested segments
Data Source
AI summary
A helmet that includes a subliner shell comprised of a hard impact resistant material. The shell has inner and outer surfaces. A subliner element having a first foam pad having a top surface and a bottom surface. The top surface is attached to the inner surface of the shell. A second foam pad is constructed of an energy absorbing viscoelastic foam material that is radially partitioned into individual segments. The segments are nested with respect to each other such that the nested segments have side surfaces in slidable direct contacting engagement with side surfaces of adjacent nested segments. The second foam pad has a top surface attached to the bottom surface of the first foam pad. A third foam pad has a top surface and a bottom surface, with the top surface of the third foam pad being attached to the bottom surface of the second foam pad.