Composite Monocoque Backrest for Lightweight Crash-Load Strength
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Solution Overview
Problem
Traditional aircraft passenger seat backrests are heavy and costly due to the use of metallic materials, which do not efficiently distribute stress loads and require additional reinforcement, limiting their structural efficiency and design flexibility.
Innovation Solution
A modular monocoque backrest design utilizing carbon fiber composite materials for the front and back shrouds, with integrated aluminum back spars and restraint systems, allowing for lightweight construction while maintaining structural integrity and enabling exterior styling without additional shrouding parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heavy metallic materials are used in the backrest structure, then the structural strength and load-bearing capacity are improved, but the weight of the backrest increases
Solution Approach 1:
The patent applies composite materials by integrating aluminum back spars within a carbon fiber reinforced plastic (CFRP) shell structure. The CFRP monocoque shell provides the primary load-bearing capability while the aluminum spars offer structural support and attachment points. This composite approach enables the backrest to achieve the required strength and stiffness for crash loads without the weight penalty of traditional all-metallic constructions, as the CFRP material provides high strength-to-weight ratio.
Solution Approach 2:
The patent changes the material parameters by transitioning from traditional metallic materials to carbon fiber reinforced plastic for the monocoque shell. This material parameter change fundamentally alters the weight-strength characteristics, allowing the structure to maintain adequate strength while significantly reducing weight. The CFRP material properties enable thin-walled construction that still withstands crash loads.
2Strength
If traditional metallic frame structures are used, then the load-bearing system is sufficient, but the device complexity and number of components increase
Solution Approach 1:
The patent merges multiple structural functions into a single integrated monocoque shell structure. The CFRP shell simultaneously serves as the load-bearing skin, the structural frame, and the mounting surface for accessories. Traditional separate components such as the outer shell, internal frame, and reinforcement elements are consolidated into one monolithic structure, reducing the number of parts and simplifying the overall assembly while maintaining load-bearing capacity.
Solution Approach 2:
The monocoque shell structure performs multiple functions: it provides the aerodynamic skin, structural support for crash loads, mounting surface for the aluminum spars, attachment points for accessories, and fire protection barrier. This multi-functional design eliminates the need for separate dedicated components for each function, reducing structural complexity while ensuring adequate load-bearing capacity through the integrated design.
3Reliability
If additional metallic reinforcement components are added, then the structural integrity under crash loads is improved, but the manufacturing cost and assembly complexity increase
Solution Approach 1:
The aluminum back spars are pre-formed and then integrated into the CFRP monocoque shell during the molding process. This preliminary preparation of the spars allows for optimized structural design before final assembly, and the integration during molding reduces subsequent assembly steps. The spars are positioned and secured within the shell structure before the final curing cycle, ensuring proper alignment and structural integrity without requiring complex post-assembly operations.
4Weight of moving object
If a monocoque shell structure is used, then the weight is reduced and structural efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The backrest structure is segmented into distinct functional zones: the CFRP monocoque shell, the aluminum back spars, and the integrated accessories. This segmentation allows each component to be manufactured and prepared separately with optimized tolerances for its specific function, then integrated as an assembly. The aluminum spars can be manufactured with precise dimensions independently, and their integration into the CFRP shell during molding accommodates reasonable tolerances without requiring ultra-precise fit-up, thus managing manufacturing precision requirements while maintaining weight benefits.
Data Source
AI summary
A modular monocoque backrest is provided. The modular monocoque backrest may comprise a front shroud, a back shroud, and an at least one back spar. The front shroud may be coupled to the back shroud, and the back spar may be configured as a mounting point, enabling the modular monocoque backrest to mount to an aircraft floor. The front shroud and the back shroud may comprise a carbon fiber composite material, allowing the modular monocoque backrest to be modular in nature. The carbon fiber composite material may enable the modular monocoque backrest to have a lightweight design while also maintaining resistance to dynamic crash loads.