Helmet with Shape Memory Alloy for Impact Energy Dissipation
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Solution Overview
Problem
Conventional protective helmets are ineffective in preventing concussions and spinal injuries during impacts, as they transfer energy to the user, leading to significant injuries in sports and other activities.
Innovation Solution
A protective helmet incorporating stress-activated active material elements, such as shape memory alloys, that dissipate energy through reversible phase transitions, reducing the energy transferred to the user's head, neck, and spine by providing greater resistance at the start of impact and less resistance as it subsides, allowing for increased travel distance and reducing concussion risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional foam or padding materials are used to absorb impact energy, then the helmet can protect against skull fractures, but the stored energy is released back to the user during decompression, causing concussions and spinal injuries
Solution Approach 1:
The patent employs shape memory alloy materials that undergo stress-induced phase transitions (austenite to martensite transformation) during impact. This phase transition allows the material to dissipate impact energy through the hysteresis loop, converting mechanical energy into thermal energy permanently, rather than storing and releasing it like conventional foams. The material transforms from a rigid austenite phase to a more compliant martensite phase during impact, absorbing energy without rebound.
2Force
If conventional padding materials are used, then they provide resistance during impact, but the resistance increases as compression progresses, accelerating the stop and increasing concussion risk
Solution Approach 1:
The shape memory alloy material dynamically changes its mechanical properties during impact through stress-induced phase transformation. The material transitions from austenite to martensite phase as stress increases, progressively changing its resistance characteristics. This dynamic phase transformation allows the material to provide appropriate resistance throughout the impact event while extending the duration of energy absorption, thereby reducing peak deceleration forces transmitted to the user's head and spine.
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 mitigates the transfer of energy during impacts, reducing the likelihood of concussions and spinal injuries by dissipating a significant portion of the impact energy, thereby enhancing user safety and providing a method for retrofitting existing helmets.
Implementation Method 1
an active material element, such as a normally Austenitic shape memory alloy wire, mesh, matrix, or spring, operable to undergo a reversible change in fundamental property when exposed to a stress activation signal
Implementation Method 2
by storing and later releasing at least a portion of the energy from an impact via the hysteresis loop of the active material
Implementation Method 3
transformation to the more malleable state will occur at some point during head travel/padding compression... transformation to the more malleable state will occur at some point during head travel/padding compression, thereby making it easier to continue to travel/compress
Data Source
AI summary
An energy dissipating helmet, such as a football, baseball, hockey, construction, combat, bicycle, or motorcycle helmet, including a structural component adapted to receive an anticipatory impact having energy, and a stress-activated active material element, such as a Austenitic shape memory alloy wire, mesh, layer, or spring, communicatively coupled to the component, and activatable by the impact, so as to dissipate at least a portion of the energy.