Helical Connecting Link With Lattice Attenuator for Aircraft Seat Crash Loads
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Solution Overview
Problem
Conventional doublers in aircraft seat assemblies do not provide energy absorption during crash scenarios, leading to unpredictable failure and inability to limit loads on seat legs.
Innovation Solution
An additively manufactured helical connecting link with an energy attenuator, featuring a helically shaped middle portion and an annular lattice structure, designed to undergo plastic deformation and relative movement when threshold forces are met, thereby attenuating impact energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional doublers are used to attach seat legs to track fasteners, then the attachment is simple and cost-effective, but the structure cannot absorb impact energy during crash scenarios leading to unpredictable failure
Solution Approach 1:
The patent changes the physical parameters of the connecting link by introducing a helical shape with specific geometric parameters (pitch, diameter, length) that control its deformation behavior. The helical geometry is designed to undergo predictable plastic deformation at specific load thresholds, transforming the rigid doubler into a energy-absorbing component with controlled failure characteristics.
Solution Approach 2:
The patent employs composite construction by combining the helical connecting link with an energy attenuator positioned within its interior space. This composite structure integrates the structural function of the connecting link with the energy absorption function of the attenuator, creating a system that both attaches components and absorbs impact energy through predictable deformation mechanisms.
2Weight of moving object
If conventional machined aluminum doublers are used, then manufacturing is straightforward, but weight and cost are higher compared to additive manufacturing
Solution Approach 1:
The patent applies local quality by using additive manufacturing to create the helical connecting link with spatially varying material distribution and geometric complexity that would be impossible or inefficient to achieve with conventional machining. The helical geometry and interior space for the energy attenuator are optimized locally for energy absorption while minimizing overall weight.
Solution Approach 2:
The patent substitutes conventional mechanical machining processes with additive manufacturing technology. This manufacturing paradigm shift enables the creation of complex helical geometries and integrated structures that reduce material usage and weight while maintaining or improving structural performance, eliminating the need for post-machining operations and assembly steps.
3Reliability
If rigid connecting links are used to attach seat legs, then structural strength is maintained, but impact energy cannot be absorbed leading to unpredictable failure during crashes
Solution Approach 1:
The patent transforms the static, rigid connecting link into a dynamic structure that adapts its mechanical properties based on applied load. The helical geometry is designed to remain rigid under normal operating conditions but undergo controlled plastic deformation when subjected to crash-level impacts. The energy attenuator within the interior space activates at specific force thresholds, enabling the structure to absorb impact energy while maintaining structural integrity during normal use.
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 enables predictable failure and energy absorption, reducing loads on seat legs and enhancing safety by limiting occupant travel during crashes, while also benefiting from reduced weight and cost through additive manufacturing.
Implementation Method 1
at least one of the helically shaped middle portion and the energy attenuator is configured to undergo plastic deformation when a threshold force on the connecting link is met
Data Source
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AI summary
A connecting link (100) for connecting first and second components such as an aircraft seat leg and a track fastener. The link (100) includes a helical middle portion (106) forming an interior space (108) in which an energy attenuator (114) is positioned. In embodiments, the energy attenuator (114) includes inner and outer cylindrical bodies (116), (118) that operate in translation upon a deformation of a lattice structure (128) configured to deform when at least one of a compressive threshold and a tensive threshold is met. In embodiments, the energy attenuator (114) receives part of one of the first and second components. The connecting link (100) may be manufactured by an additive manufacturing process and used in an aircraft leg assembly to save weight and absorb impact energy on the leg.