Aluminum Honeycomb Helmet Liner for Multi-Impact Attenuation
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Solution Overview
Problem
Current helmet impact attenuation systems, particularly those using expanded polystyrene (EPS), face challenges in providing adequate protection over multiple impacts due to increased size and weight, with EPS showing reduced protection after a single impact and being less effective in subsequent impacts.
Innovation Solution
The use of a pre-crushed aluminum honeycomb sheet with a polymer skin, configured to provide different levels of impact attenuation by varying the thickness and geometry, including slits to allow curvature and integration with a helmet liner, offering improved performance across multiple impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EPS is used for impact attenuation, then the helmet can provide protection for single impact, but the helmet size increases due to the thickness of EPS needed
Solution Approach 1:
The patent changes the material parameter from EPS foam to aluminum honeycomb structure, which has different density and energy absorption characteristics. This allows achieving the same impact protection with reduced thickness, thereby reducing helmet volume while maintaining reliability
Solution Approach 2:
The patent uses aluminum honeycomb as a composite material structure that combines the strength of aluminum with the energy-absorbing characteristics of the honeycomb geometry. This composite structure provides superior impact attenuation per unit thickness compared to EPS, resolving the contradiction between protection and size
2Weight of moving object
If EPS is used for impact attenuation, then the helmet can be made lightweight, but the protection is reduced after a second impact
Solution Approach 1:
The patent changes from EPS foam to aluminum honeycomb material, which has different mechanical properties including higher elasticity and energy recovery characteristics. This allows the material to maintain protective performance across multiple impacts while keeping the helmet lightweight
Solution Approach 2:
Instead of using a material that permanently deforms to absorb impact energy (EPS), the patent uses aluminum honeycomb that can elastically recover and reuse its energy absorption capacity. This inverted approach to energy management enables multi-impact protection without sacrificing weight efficiency
3Reliability
If aluminum honeycomb sheet is pre-crushed and slitted to provide different levels of impact attenuation, then the impact protection performance is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent divides the aluminum honeycomb sheet into multiple regions separated by slits, creating zones with different thicknesses and energy absorption characteristics. This segmentation allows tailoring impact attenuation to specific helmet areas while using relatively simple cutting and crushing operations
Solution Approach 2:
The patent applies local quality by pre-crushing and varying the thickness of aluminum honeycomb in specific regions to provide different levels of impact attenuation where needed. This allows optimization of protection in high-impact areas without unnecessarily increasing complexity across the entire helmet 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 pre-crushed aluminum honeycomb sheet with a polymer skin enhances impact attenuation by maintaining consistent energy absorption across multiple impacts, reducing the overall thickness and weight of the helmet liner, while meeting stringent impact protection requirements.
Implementation Method 1
The pre-crushed aluminum honeycomb sheet with a polymer skin enhances impact attenuation by maintaining consistent energy absorption across multiple impacts
Data Source
AI summary
An impact attenuation system comprises an aluminum honeycomb sheet having a top surface and a bottom surface. The aluminum honeycomb sheet defines a plurality of approximately hexagonally shaped cells. The bottom surface defines a single sheet of contiguous cells and the top surface defines two or more islands of contiguous cells separated by one or more slits. At least a portion of one or both of the top surface and bottom surface may be covered by a polymer skin. The polymer skin may comprise carbon fibers and/or fiberglass.