Integrated Composite Shell Element Co-Curing Process
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Solution Overview
Problem
The existing manufacturing processes for aircraft and spacecraft fuselages are cumbersome and weight-intensive due to the use of rivets and adhesives for assembling composite shell elements, which also complicate system installations and increase costs.
Innovation Solution
A process involving the co-curing of resin-impregnated fibers to form integrated shell elements with longitudinal or transverse stiffeners, eliminating the need for rivets and reducing assembly complexity by using prepregs and autoclaving, and incorporating stiffener elements with open cross-profiles for simplified bracket assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rivets or adhesives are used to assemble shell elements and stiffeners, then structural strength is achieved, but weight increases and assembly complexity increases
Solution Approach 1:
The shell element and stiffener are merged into a single integrated component by co-curing resin-impregnated fibers in a single autoclaving process. The stiffener and shell are formed simultaneously from separate prepreg layers that are laminated together and cured together, eliminating the need for separate assembly operations and the associated fasteners or adhesives.
Solution Approach 2:
The stiffener and shell components are prepared in advance as pre-impregnated fiber layers (prepregs) with predetermined shapes and positions. These prepreg layers are designed with open cross-profiles and specific geometries before assembly, allowing for simplified integration during the single curing process while maintaining structural strength.
2Strength
If rivets or adhesives are used to assemble shell elements and stiffeners, then structural strength is achieved, but manufacturing complexity and costs increase
Solution Approach 1:
The manufacturing process merges multiple operations into a single autoclaving step where both the shell and stiffener are cured simultaneously. This eliminates sequential assembly steps involving riveting or adhesive bonding, reducing manufacturing complexity and costs while maintaining structural integrity.
Solution Approach 2:
Components are pre-formed as shaped prepreg layers with predetermined geometries and positions before the final curing process. This preliminary preparation allows for complex shapes to be achieved without complex assembly operations, simplifying the overall manufacturing process.
3Reliability
If traditional assembly methods with rivets and adhesives are used, then structural integrity is maintained, but system installation becomes difficult and time-consuming
Solution Approach 1:
The integration of stiffener and shell into a single monolithic structure eliminates interfaces that would require separate fastening operations. System installations can access the structure through the open cross-profiles without needing to disassemble or work around rivets or adhesive bonds, improving ease of operation while maintaining structural integrity.
Solution Approach 2:
The open cross-profile design of the stiffener acts as an intermediary feature that provides access pathways for system installations. This geometric feature serves as a mediator between the structural requirements and the installation requirements, allowing both objectives to be achieved simultaneously.
4Strength
If multiple separate components are assembled using rivets or adhesives, then structural strength is achieved, but production time increases
Solution Approach 1:
The production process combines the manufacturing of the shell and stiffener into a single autoclaving operation. Multiple prepreg layers are laminated and cured simultaneously in one cycle, eliminating the time required for sequential assembly operations while producing a structurally sound integrated component.
Solution Approach 2:
Prepreg layers are prepared in advance with predetermined shapes and positions, allowing for rapid assembly and single-step curing. This preliminary preparation enables quick integration of components without time-consuming alignment and fastening operations, significantly improving production speed.
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 process simplifies the manufacturing of fuselage components, reduces weight, minimizes noise, and facilitates quicker system installations by avoiding the limitations of adhesive bonding and riveting, while maintaining structural integrity.
Implementation Method 1
curing in a single step said plurality of resin impregnated fibers laid-up in steps (ii) and (iv) such that the plurality of fibers forming the shell element and the plurality of fibers forming the at least one stiffener element are laminated into an integrated shell element
Implementation Method 2
the plurality of fibers forming the shell element and the plurality of fibers forming the at least one stiffener element are laminated into an integrated shell element
Data Source
AI summary
A process for manufacturing an integrated shell element including: providing a shell element lay-up tool with an upper tool surface; laying-up a resin impregnated fibers on the upper tool surface to form the shell element; providing on the resin impregnated fibers a stiffener element layup tool having surfaces to support a stiffener element structure; laying-up resin impregnated fibers on the stiffener element lay-up tool to form the stiffener element; curing in a single step the resin impregnated fibers such that the fibers forming the shell element and the fibers forming the stiffener element are laminated into an integrated shell element having a longitudinal or transversal stiffener element; and separating the integrated shell element from the shell element and stiffener element lay-up tools.