Hyperelastic Impact Attenuator Rebound Control
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Solution Overview
Problem
Existing impact attenuator systems for vehicles are either rigid, causing vehicle damage and rebound issues, or one-time use, being costly and requiring frequent replacement, with a need for a system that minimizes occupant injury, is fully recoverable, economical, and effective across various environments.
Innovation Solution
A cast thermoset polyurethane elastomeric composition-based impact attenuator system with hyperelastic members, featuring a specific mixture and processing steps, and a design with nested side panels and diaphragm panels secured by cables, allowing for energy absorption and controlled rebound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid barrier structures are used to restrain vehicles, then the barrier provides strong restraint capability, but the vehicle suffers severe crushing damage and rebound occurs into oncoming traffic
Solution Approach 1:
The barrier transitions from a rigid structure to a flexible structure by changing the physical state and mechanical properties of the material. The flexible barrier uses high-performance polymer fibers with elongation at break of 30-100% to absorb impact energy through controlled deformation, converting the harmful rigid impact into a beneficial energy absorption process that reduces vehicle damage while maintaining restraint capability
Solution Approach 2:
The flexible barrier is constructed as a composite structure combining high-performance polymer fibers (such as aramid, polyethylene, or polyester) embedded in a matrix material. This composite construction provides both the flexibility needed for energy absorption and the strength required for vehicle restraint, resolving the contradiction between rigidity and damage reduction
2Loss of energy
If one-time collapsible energy absorbing materials are used, then the barrier absorbs impact energy effectively, but the barrier must be replaced after single impact which is time consuming and expensive
Solution Approach 1:
The flexible barrier is designed as a dynamic, reusable system that can undergo repeated loading and unloading cycles. The high-performance polymer fibers maintain their mechanical properties after impact, allowing the barrier to be reset and reused multiple times, eliminating the need for replacement and reducing both time and cost losses
Solution Approach 2:
Instead of discarding the barrier after single use, the flexible barrier system recovers and reuses the same barrier structure repeatedly. The energy-absorbing materials are designed to return to their original state after impact, enabling continuous recovery and reuse without degradation of performance
3Force
If traditional energy absorbing materials are used, then the barrier provides some rebound control, but the rebound force is insufficiently controlled and the barrier lacks consistency across various velocities
Solution Approach 1:
The barrier incorporates materials with specifically controlled mechanical parameters, particularly elongation at break of 30-100% and controlled stress-strain characteristics. These parameter optimizations ensure consistent energy absorption and rebound control across a wide range of impact velocities, from low-speed to high-speed collisions
Solution Approach 2:
The flexible barrier uses varying densities and fiber orientations in different regions to optimize performance for different impact scenarios. The material properties are locally optimized to provide consistent rebound control regardless of impact velocity, with tougher materials in high-stress zones and more compliant materials in energy-absorption zones
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 system effectively absorbs impact energies, reduces rebound force, and remains fully recoverable, maintaining consistent force-displacement characteristics across a range of velocities, while being economical and durable enough to withstand multiple impacts without debris dispersal.
Implementation Method 1
hyperelastic member, wherein the hyperelastic member comprises an energy absorbing material that behaves in a rate-independent hyperelastic manner
Implementation Method 2
the energy absorbing material maintains consistent force-displacement characteristics over a wide range of impact velocities while remaining fully recoverable
Data Source
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AI summary
An impact attenuator system including a hyperelastic member that comprises an energy absorbing material with a tan d of not less than about 0.05 to assist rebound control.