Releasable Convoluted Tensile Member for Gradual Impact Deceleration
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Solution Overview
Problem
Existing energy absorbing systems often cause damage to vehicles and their occupants due to rapid deceleration, and are unable to effectively stop moving objects like vehicles and projectiles without causing significant harm.
Innovation Solution
A flexible tensile member system with convolute portions held by energy-absorbing connectors that absorb energy through cyclical tension changes, allowing gradual deceleration and reconfiguration to arrest moving objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional energy absorbing systems are used to stop moving objects, then the objects are stopped quickly, but the vehicles and occupants experience too much force causing damage and injury
Solution Approach 1:
The flexible tensile member transitions from a static constrained structure to a dynamic system that adapts its stiffness during deceleration. The convoluted configuration allows the member to progressively unfold and extend, changing its mechanical properties in real-time to provide initial rigidity for energy absorption followed by gradual compliance for smooth deceleration, thereby reducing peak forces on vehicles and occupants
Solution Approach 2:
The system changes the physical state and configuration of the flexible tensile member during operation. The member transitions from a compact convoluted state with high stiffness to an extended state with lower stiffness, effectively changing the deceleration parameter over time. This parameter change allows the system to absorb energy rapidly initially then transition to a gentler deceleration profile
2Force
If energy absorbing systems are designed to stop heavy trucks at high speed, then stopping capability is improved, but the system cannot effectively stop smaller vehicles at lower speeds without causing damage
Solution Approach 1:
The flexible tensile member's dynamic unfolding process creates a time-varying force profile that adapts to different impact scenarios. For heavy trucks at high speed, the member extends fully providing prolonged deceleration. For smaller vehicles at lower speeds, the member unfolds partially or remains constrained, automatically adjusting the force magnitude to match the impact energy and prevent damage
Solution Approach 2:
The system utilizes changes in the flexible tensile member's configuration parameters (convolution degree, extension length) to modulate the stopping force. The energy-absorbing connectors control these parameter changes, allowing the system to deliver appropriate force levels for different vehicle sizes and speeds, effectively protecting both heavy trucks and smaller vehicles
3Stability of the object's composition
If the flexible tensile member uses fixed connectors to maintain convoluted configuration, then structural stability is improved, but the member cannot absorb energy through reconfiguration
Solution Approach 1:
The flexible tensile member is divided into multiple segments or convolutions that can be independently constrained or released. The energy-absorbing connectors are positioned at specific locations to constrain certain convolutions while allowing others to unfold. This segmentation enables selective energy absorption while maintaining overall structural stability during the deceleration process
Solution Approach 2:
The connectors transition from a static constrained state to a dynamic release mechanism during impact. The connectors are designed to fail or release at predetermined moments, allowing the convoluted configuration to dynamically transform from a stable compact form to an extended energy-absorbing form, thereby enabling both structural stability and energy absorption
4Loss of energy
If the flexible tensile member is made very long to absorb more energy, then energy absorption capacity is improved, but the system size and space requirements increase
Solution Approach 1:
The flexible tensile member is configured in a convoluted or folded state that nests multiple lengths of the member within a compact space. The convolutions allow a long member to be packed into a short constrained length, enabling high energy absorption capacity without requiring a long installed footprint. During deceleration, the nested convolutions unfold sequentially to absorb energy over an extended distance
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 minimizes damage to moving objects and reduces injury by gradually dissipating kinetic energy, enabling safe deceleration of vehicles and projectiles.
Implementation Method 1
a flexible tensile member (e.g., a cable, chain, and/or strap) that is configured to absorb energy from a moving object in a cyclical manner so that the flexible tensile member experiences a first increase in tension, a first decrease in tension, and a second increase in tension during the time that the moving object is decelerated
Data Source
AI summary
An energy absorber includes a flexible tensile member having lengthwise sections arranged serially along a length of the flexible tensile member. Lengthwise sections define convolutions. Features are provided for both restricting straightening of the convolutions and automatically reconfiguring, in response predetermined tension in the flexible tensile member, to allow straightening of the convolutions.