Additively Manufactured Strut With Lattice Crush Energy Absorption
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Solution Overview
Problem
Current aircraft passenger seat components lack energy absorbing and load limiting features, leading to unpredictable plastic deformations and structural failures during crashes, resulting in occupant injury and seat damage.
Innovation Solution
An additively manufactured energy absorbing strut device with a cylinder body, piston, and deformable elements, including an annular lattice structure and crushable tube, that undergo predictable plastic deformation to absorb impact energy and limit loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional manufacturing processes are used for seat components, then manufacturing simplicity is maintained, but energy absorption capability and predictable failure mechanisms are lacking
Solution Approach 1:
The strut device is divided into distinct functional segments: a cylinder body portion and a piston portion with deformable elements. This segmentation allows each component to be optimized for its specific function (energy absorption, load limitation) while maintaining overall structural integrity, resolving the contradiction between energy absorption capability and structural complexity
Solution Approach 2:
The patent utilizes additive manufacturing to change the manufacturing parameters and enable complex geometries (lattice structures, variable density regions) that are impossible with conventional manufacturing. This parameter change allows the strut to achieve predictable failure mechanisms and energy absorption characteristics without compromising manufacturability
2Reliability
If seat components are designed without energy absorbing features, then manufacturing simplicity is maintained, but reliability during crash scenarios deteriorates
Solution Approach 1:
The deformable elements (lattice structures, crushable features) are pre-designed with specific geometric configurations that ensure predictable failure modes at predetermined load thresholds. This preliminary action during design ensures reliable energy absorption during crashes without requiring complex control systems or additional components
Solution Approach 2:
The strut device employs composite structural designs combining solid metal regions with lattice structures and hollow crushable elements. This composite approach enables predictable progressive collapse mechanisms that enhance reliability during impact while maintaining reasonable design complexity
3Manufacturing precision
If additive manufacturing is used for the strut device, then manufacturing precision and customizable geometries are improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the cylinder body and piston portions into a single additively manufactured component. This consolidation eliminates the need for separate manufacturing processes, assembly steps, and associated tolerances, thereby improving geometric precision while actually simplifying the manufacturing process despite the complex geometry
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 strut device provides controlled energy absorption and load limitation, preventing structural failures and reducing injury risk by utilizing additive manufacturing for customizable, predictable failure mechanisms.
Implementation Method 1
An energy absorbing strut device with a cylinder body, piston, and deformable elements, including an annular lattice structure and crushable tube, that undergo predictable plastic deformation to absorb impact energy and limit loads
Data Source
AI summary
An additively manufactured strut device including a cylinder body forming a chamber and a piston having a first part disposed in the internal chamber and a second part disposed outside of the chamber. A first deformable element formed as a lattice structure breaks to permit initial withdrawal of the piston when a tensive threshold is met and a second deformable crushes during continued withdrawal of the piston. In further embodiments, a third deformable element formed as a lattice structure may be collocated with the second deformable element. The strut may be manufactured by an additive manufacturing process. Applications for the energy absorbing strut include aircraft seat frames among other applications.