Viscoelastic Polymer Impact Absorbing Layer Football Helmet
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Solution Overview
Problem
Current football helmets lack significant improvements in shock absorption and impact attenuation, failing to adequately protect players from concussion injuries, which can lead to long-term cognitive and physical health issues due to increased player strength and speed.
Innovation Solution
A football helmet design featuring a shell made of fiber-reinforced epoxy resin with an energy-absorbing layer of expanded polypropylene and a viscoelastic polymer-based energy-absorbing layer, providing enhanced impact attenuation and shock absorption, along with a lightweight construction to reduce transmitted impact forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional helmet liners are used, then the helmet structure is simple, but the impact absorption capability is insufficient
Solution Approach 1:
The helmet liner is divided into multiple independent layers: an outer energy-absorbing layer made of viscoelastic polymer and an inner comfort layer made of expanded polypropylene. Each layer performs a specific function - the outer layer absorbs impact energy through viscous deformation, while the inner layer provides comfort and conforms to the head shape. This segmentation allows each layer to be optimized for its specific purpose, improving overall impact absorption without excessive complexity.
Solution Approach 2:
The helmet employs a composite structure combining two different materials with complementary properties: viscoelastic polymer for impact energy absorption and expanded polypropylene for comfort and conformability. The viscoelastic material provides nonlinear stress-strain behavior that dissipates impact energy, while the expanded polypropylene offers lightweight cushioning and head conformity. This composite approach achieves superior impact protection that neither material could provide alone.
2Productivity
If player strength and speed increase, then athletic performance improves, but impact forces on the head increase
Solution Approach 1:
The viscoelastic polymer's mechanical properties change with temperature and strain rate, allowing it to adapt to different impact conditions. At higher strain rates typical of football impacts, the material becomes stiffer and absorbs more energy. The nonlinear stress-strain relationship of the viscoelastic material allows it to provide progressive resistance during impact, matching the increasing forces generated by stronger, faster players without requiring active adjustment mechanisms.
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 design significantly reduces impact forces on the player's head, offering improved protection against concussions and potential long-term health risks by enhancing the helmet's ability to absorb and distribute impact energy.
Implementation Method 1
the energy absorbing layer is situated between the liner and the shell in the crown area of the shell
Implementation Method 2
the energy absorbing layer has a higher compressive strength than the compressive strength of the liner
Implementation Method 3
a viscoelastic polymer-based energy-absorbing layer, providing enhanced impact attenuation and shock absorption
Data Source
AI summary
A football helmet is disclosed that includes a shell constructed of fiber reinforced epoxy resin, a liner made from expanded polypropylene, an impact absorbing layer situated between the liner and the shell, and a face gaurd. The impact absorbing layer is constructed from either expanded polypropylene or a viscoelastic polymer encased in a suitable thin yet resilient and elastic membrane. An optional impact absorbing band is also shown disposed around the inner periphery of the liner and encircling the player's head. The impact absorbing band serves to reduce impact forces occurring from side helmet impact with objects or players. An alternate helmet liner is also disclosed having hexagonal apertures situated in the crown thereof to lower the density of the EPP material in that region and improve energy absorbing characteristics of the helmet assembly.