Multi-material Protective Helmet with Segmented Shell
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Solution Overview
Problem
Existing protective helmets face challenges in being both lightweight and compact while providing adequate shock absorption, with materials like expanded polystyrene being fragile and heavy, and expanded polypropylene being less effective at shock absorption but more flexible and bulky.
Innovation Solution
A protective helmet design featuring a cap made of expanded polypropylene with a thermoformed shell covering a shock-absorbing element, where the shell is mechanically and chemically linked to the cap, reducing weight by limiting the shell's coverage to the top part and using materials like polycarbonate or Kevlar for enhanced impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If expanded polystyrene is used for the helmet cap, then shock absorption is improved, but weight increases and the helmet becomes less compact
Solution Approach 1:
The helmet is divided into two functional zones: a top part with a shell and shock-absorbing element for impact protection, and side/rear parts made of expanded polypropylene for lightweight coverage. This segmentation allows optimized shock absorption where needed while minimizing weight elsewhere.
Solution Approach 2:
Different materials and structures are applied to different regions of the helmet. The top part receives enhanced protection with shell and shock-absorbing elements, while other regions use lighter expanded polypropylene material, creating local quality variations that optimize both protection and weight.
2Weight of moving object
If expanded polypropylene is used for the helmet cap, then weight is reduced, but shock absorption capability deteriorates
Solution Approach 1:
The helmet structure is segmented into a top protective zone with shell and shock-absorbing elements, and lower weight zones using expanded polypropylene. This allows the heavy protective components to be localized only where most needed for shock absorption.
Solution Approach 2:
The helmet combines multiple materials: shell material (polycarbonate, acrylonitrile butadiene styrene, polyethylene, glass fiber, carbon fiber, or poly(p-phenyleneterephthalamide) fiber), shock-absorbing element (expanded polystyrene), and cap material (expanded polypropylene). This composite approach leverages the strengths of each material in specific locations.
3Reliability
If the shell covers the entire helmet, then protection is improved, but weight increases
Solution Approach 1:
The shell coverage is extracted from being universal to being selective - it is applied only to the top part of the helmet where impact protection is most critical, removing unnecessary shell material from other regions to reduce weight.
Solution Approach 2:
The shell is applied locally only to the top part of the cap rather than covering the entire helmet, creating a localized quality enhancement that provides maximum protection where needed while minimizing added weight.
4Weight of moving object
If the shell is placed only on the top part, then weight is reduced, but protection coverage is limited
Solution Approach 1:
The helmet is segmented into a protected top zone with shell and shock-absorbing elements, and unprotected zones made of expanded polypropylene. This segmentation strategically places protection only where most needed while accepting limited coverage elsewhere to reduce weight.
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 results in a helmet that is 30% lighter than similar designs, maintaining effective shock absorption and compactness, with improved impact resistance and user comfort through strategic placement and material selection.
Implementation Method 1
a shock-absorbing element filling the through-hole... suitable to absorb shocks and protect the user
Implementation Method 2
the shock-absorbing element being linked mechanically with the main part and chemically with the shell, so that the main part, the shock-absorbing element and the shell are integral
Data Source
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AI summary
The invention relates to a protective helmet (1) comprising: • a shell (2) having: ∘ a main part (2a) made of expanded polypropylene defining a through hole in its apex, ∘ a shock-absorbing element filling the through hole, • a shell (3) fixed to the apex of the shell (2) and covering the through hole, the shock-absorbing element being mechanically bonded to the main part (2a) and chemically bonded to the shell (3), such that the main part (2a), the shock-absorbing element, and the shell (3) are integral. The invention also relates to a method for manufacturing such a protective helmet.