Protective Helmet Rotational Stress Reduction via Shear Deformation

Solution Overview

Problem

Conventional protective helmets are ineffective in reducing rotational stresses on the head during impacts, leading to increased weight, manufacturing complexity, and higher fatigue due to their complex double-shell structure, which is costly and heavy.

Innovation Solution

A protective helmet design featuring a shell with an outer and inner padding system where the outer shell is made more rigid and the inner padding is made of deformable materials, allowing for energy dissipation through shear deformation and relative movement between the padding layers, reducing rotational accelerations transmitted to the head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a double-shell structure with outer and inner shells is used to reduce rotational stresses, then the protective capability against rotational accelerations is improved, but the weight and device complexity increase

Engineering Contradiction:

Improveprotective capability against rotational accelerationsVSAvoidhelmet weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The helmet is divided into an outer shell and an inner shell with distinct functions. The outer shell provides rigid protection against impact forces, while the inner shell with deformable padding absorbs and dissipates rotational energy through controlled deformation, separating the protection mechanisms into functional segments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The helmet employs composite construction combining rigid outer shell material with deformable padding materials. This composite approach allows the structure to exhibit both rigid-body resistance to impact and controlled deformation characteristics for rotational energy dissipation, achieving multiple protective functions through material composition.

Inventive Principle:

Principle #40Composite materials

2Reliability

If a double-shell structure with outer and inner shells is used to reduce rotational stresses, then the protective capability against rotational accelerations is improved, but the manufacturing complexity and cost increase

Engineering Contradiction:

Improveprotective capability against rotational accelerationsVSAvoidhelmet structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The helmet is divided into an outer shell and an inner shell with distinct functions. The outer shell provides rigid protection against impact forces, while the inner shell with deformable padding absorbs and dissipates rotational energy through controlled deformation, separating the protection mechanisms into functional segments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the material parameters of the padding layer, making it deformable under rotational stresses. This parameter change allows the inner shell to dissipate energy through controlled deformation rather than rigid resistance, simplifying the overall structure while maintaining protective effectiveness.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the helmet mass is increased to improve protective capability, then the energy absorption capacity is improved, but the user fatigue and comfort deteriorate

Engineering Contradiction:

Improveenergy absorption capacityVSAvoiduser comfort and fatigue

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The invention changes the material parameters of the padding layer, making it deformable under rotational stresses. This parameter change allows the inner shell to dissipate energy through controlled deformation rather than rigid resistance, simplifying the overall structure while maintaining protective effectiveness.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The inner shell and padding system are designed to dynamically respond to impact forces. During normal use, the helmet remains lightweight and comfortable. During impact, the deformable padding dynamically absorbs and dissipates energy, providing enhanced protection only when needed without the constant weight penalty.

Inventive Principle:

Principle #15Dynamics

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 helmet effectively reduces rotational stresses on the head during impacts, maintaining safety while minimizing weight and manufacturing costs, allowing for reduced fatigue and improved comfort.

Implementation Method 1

The inner padding is made of deformable materials, allowing for energy dissipation through shear deformation

Methodology Applied

Scientific EffectShear deformation: Deformation

Implementation Method 2

allowing for energy dissipation through shear deformation and relative movement between the padding layers

Methodology Applied

Scientific EffectEnergy dissipation: Damping

Implementation Method 3

relative movement between the padding layers

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentEP3357364B1Protective helmet

Publication Date: 2024.05.15 ANOMALY ACTION SPORTS SRL

Figure 1~2
Figure 3~7
Figure 8~11

AI summary

A protective helmet comprises a shell (2) provided with an outer surface (3) and an inner surface (4), at least one pad (7) adapted, in use, to abut against the head of a user who wears the protective helmet, comprising at least one first surface (8) and a second surface (9) that are opposite each other, elements (10) connecting the at least one pad to the shell (2), wherein the at least one pad (7) is shaped as a substantially laminar body (11) and is configured to allow the sliding and/or the relative rotation between the at least one first surface (8) and the second surface (9).