Energy Attenuating Mounting Foot for Aircraft Cabin Seats
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Solution Overview
Problem
Aircraft cabin fixtures secured to tracks face challenges in distributing mechanical loads effectively, leading to potential separation and failure under dynamic loads due to concentrated stress concentrations.
Innovation Solution
An energy attenuating mounting foot with a load beam and laterally extending interface lobes, featuring a channel for deformation, is designed to distribute loads evenly by engaging with the track only under load, made from materials like martensitic precipitation-hardening stainless steel, allowing for plastic deformation and attachment to the track.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a mounting foot is rigidly attached to the track, then the mechanical load is transmitted effectively, but stress concentrations cause separation and failure under dynamic loads
Solution Approach 1:
The mounting foot material undergoes a parameter change from rigid to plastically deformable under load. The channel feature enables controlled plastic deformation that absorbs energy and reduces stress concentrations, allowing the mounting foot to maintain attachment under dynamic loads while still transmitting mechanical loads effectively.
Solution Approach 2:
The channel feature is pre-formed in the mounting foot to provide a predetermined deformation zone. This beforehand cushioning allows the mounting foot to absorb impact energy through controlled plastic deformation before stress concentrations can cause separation or failure, improving reliability under dynamic loads.
2Reliability
If the mounting foot is made from soft material, then plastic deformation occurs to attenuate loads, but the load beam lacks sufficient strength to maintain attachment
Solution Approach 1:
The mounting foot exhibits local quality differentiation: the channel region is designed to be softer and more deformable for load attenuation, while the overall structure maintains sufficient strength through material selection (martensitic precipitation-hardening stainless steel) and geometric design. This allows localized plastic deformation without compromising overall attachment strength.
Solution Approach 2:
The mounting foot utilizes martensitic precipitation-hardening stainless steel, which combines the ability to undergo controlled plastic deformation with high ultimate strength. This composite-like material behavior enables both load attenuation through deformation and maintenance of attachment strength under dynamic loads.
3Ease of operation
If the mounting foot is designed for easy installation and reconfiguration on tracks, then fixtures can be repositioned freely, but the connection may fail under high dynamic loads
Solution Approach 1:
The mounting foot transitions from a static rigid connection to a dynamic system that can deform plastically under load. The channel feature enables the mounting foot to adapt its geometry in response to applied loads, maintaining connection reliability while preserving the ability to be repositioned during normal operation.
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 effectively attenuates loads, reducing stress concentrations and preventing separation, ensuring the mounting foot remains attached to the track even under high dynamic loads like 16 G forces, thereby enhancing the reliability of aircraft interior fixtures.
Implementation Method 1
the load beam undergoes plastic deformation across the channel in response to a load placed on the load beam
Implementation Method 2
the load beam comprises a martensitic precipitation-hardening stainless steel
Data Source
AI summary
In various embodiments, the present disclosure provides an energy attenuating mounting foot comprising a load beam having a longitudinal axis, a top surface, a bottom surface, an inner track interface lobe, and an outer track interface lobe, the inner track interface lobe and the outer track interface lobe extending laterally from the load beam, and a channel along the longitudinal axis having a depth extending from the load beam bottom surface toward the top surface. In various embodiments, the inner track interface lobe has a first length extending in a direction from the bottom surface towards the top surface and the outer track interface lobe has a second length extending in a direction from the bottom surface towards the top surface, the first length being less than the second length.