One-Piece Mandrel for Seamless Composite Fuselage Sections
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Solution Overview
Problem
Current composite lay-up fuselage manufacturing methods for aircraft require multi-piece sections and seals, leading to increased weight, cost, and leakage issues during autoclave curing, which complicates the process and diminishes vacuum integrity.
Innovation Solution
A one-piece cylindrical inner mandrel shell with a thin lay-up mandrel element and caul plates forms a continuous lay-up surface, allowing for the lay-up of resin impregnated stiffener and skin fibers without seals, enabling vacuum integrity and the production of a unitary seamless fuselage section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multi-piece sections are used for fuselage manufacturing, then the fuselage can be assembled from manageable sections, but the weight and cost increase due to longitudinal splices and seal requirements
Solution Approach 1:
The fuselage manufacturing process is segmented into manageable stages using a multi-sectional tooling system that can produce continuous fuselage sections. The tooling itself is divided into multiple sections that can be assembled and disassembled, allowing the manufacturing process to handle large-scale production while maintaining the ability to create seamless fuselage sections.
Solution Approach 2:
Multiple fuselage sections are merged into a single continuous structure through longitudinal splicing. The invention combines several manageable tooling sections to produce a seamless fuselage section, eliminating the need for seals between tooling sections while maintaining the practical benefits of sectional manufacturing.
2Area of stationary object
If multi-sectional tooling with seals is used, then the tooling can accommodate large fuselage sections, but vacuum integrity is compromised due to seal leakage
Solution Approach 1:
The tooling is divided into multiple sections that can be assembled to cover large fuselage areas. Each section is designed with self-contained vacuum sealing capabilities, allowing the entire tooling assembly to maintain vacuum integrity across the full coverage area without requiring seals between sections.
Solution Approach 2:
A vacuum distribution system acts as an intermediary between the autoclave and the fuselage skin, distributing vacuum pressure uniformly across the entire tooling assembly. This intermediary system ensures that vacuum integrity is maintained across multiple tooling sections without relying on seals between them.
3Ease of manufacture
If longitudinal splices are used between fuselage sections, then the fuselage can be constructed from manageable parts, but the weight and cost increase
Solution Approach 1:
The fuselage is divided into multiple sections for manufacturing purposes, with each section produced using the same seamless tooling process. This segmentation allows for manageable production while eliminating the need for weight-added splices, as each section is manufactured as a continuous piece.
Solution Approach 2:
The manufacturing approach changes from assembling spliced sections to producing continuous sections that can be joined without traditional splicing. By changing the manufacturing parameters to use seamless tooling and continuous fiber layup, the weight penalty associated with longitudinal splices is eliminated.
4Productivity
If seals are used between tooling sections, then the tooling can be sectional for large-scale production, but the complexity and cost increase
Solution Approach 1:
The tooling is segmented into multiple sections to enable large-scale fuselage production, but each section is designed as a self-contained unit with integrated vacuum sealing. This segmentation increases productivity by allowing modular assembly while avoiding the complexity of inter-sectional seals.
Solution Approach 2:
Each tooling section is designed to be universal and multi-functional, capable of operating independently with its own vacuum sealing system. This universality allows sections to be assembled in different configurations for different fuselage sizes without requiring complex seal arrangements.
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
This method reduces weight and cost by eliminating the need for seals and ensuring vacuum integrity during curing, resulting in a lighter and more cost-effective unitary seamless aircraft fuselage section.
Implementation Method 1
laying up a plurality of resin impregnated skin fibers onto the lay-up surface while the mandrel rotates to form a unitary pre-cured section of an aircraft fuselage
Data Source
AI summary
A method of manufacturing a unitary seamless section of an aircraft fuselage comprises disposing a thin lay-up mandrel element onto the outer shell surface of a cylindrical inner mandrel shell, thereby forming a mandrel with a lay-up surface. A plurality of resin impregnated stiffener fibers may be layed-up within a plurality of stiffener channels in the lay-up surface to form a plurality of stiffeners or stringers. The method further includes laying up a plurality of resin impregnated skin fibers onto the lay-up surface while the mandrel rotates to form a unitary pre-cured section of an aircraft fuselage.