Composite Fuselage Structure Thermal Demolding
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Solution Overview
Problem
Current composite material structures for aircraft fuselages require multiple operations for assembly and integration of outer panels with stiffeners, leading to increased manufacturing time and weight, as well as mechanical interferences during demolding.
Innovation Solution
A closed composite material structure is formed on a male jig with a higher thermal expansion coefficient than the composite material, allowing for single-operation separation and integration of a single outer panel with inner longitudinal stiffeners, using a leak-tight tubular male jig and an autoclave curing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multiple operations are used to assemble outer panels with stiffeners, then structural integration is achieved, but manufacturing time and weight increase
Solution Approach 1:
The patent merges the outer panel and inner longitudinal stiffeners into a single integrated composite structure manufactured in one operation. The stiffeners are positioned within the mold cavity before the panel is formed, allowing simultaneous curing of both components as a single monolithic piece, eliminating multiple assembly operations.
Solution Approach 2:
The stiffeners are pre-positioned within the mold cavity before the composite material is applied and cured. This preliminary arrangement ensures proper positioning and integration of stiffeners into the final structure without requiring subsequent assembly operations.
2Stability of the object's composition
If multiple operations are used to assemble outer panels with stiffeners, then structural integration is achieved, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process is simplified by combining multiple assembly operations into a single molding operation. The mold cavity is designed to accommodate both the outer panel and internal stiffener structure, allowing both components to be formed and cured simultaneously in one operation, reducing process complexity.
Solution Approach 2:
The mold cavity is segmented into regions that can independently form different components (panel and stiffeners), allowing complex integrated structures to be manufactured using standardized molding processes without requiring complex multi-step assembly procedures.
3Strength
If traditional assembly methods are used, then panel connection is achieved, but mechanical interferences during demolding occur
Solution Approach 1:
The mold is designed with separation lines and release agents at strategic locations to enable clean demolding of the integrated structure. The stiffeners and panel are formed as separate but integrated components within the mold, allowing them to be released together without mechanical interference or damage.
Solution Approach 2:
Release agents or parting lines are used as intermediaries between the mold cavity and the cured composite structure, enabling smooth demolding without mechanical interference. These intermediaries allow the stiffeners and panel to be separated from the mold walls without causing damage or interference.
4Weight of moving object
If composite materials are used, then weight reduction is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The stiffeners are pre-positioned within the mold cavity before the composite material is applied. This preliminary positioning ensures precise alignment and integration of stiffeners with the outer panel, achieving high manufacturing precision while maintaining the weight advantages of composite materials.
Solution Approach 2:
The mold cavity geometry and curing parameters are optimized to ensure precise integration of stiffeners and panel. By controlling temperature, pressure, and curing time parameters, the composite material achieves precise bonding with the pre-positioned stiffeners, achieving high integration precision.
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 approach enables efficient weight reduction, reduced manufacturing time, and seamless demolding by creating a clearance between the structure and jig, facilitating the integration of multiple parts into larger components while ensuring surface quality and mechanical interference-free separation.
Implementation Method 1
the expansion coefficient of the male jig is greater than the expansion coefficient of the composite material of the structure
Implementation Method 2
curing the closed structure in high temperature and pressure conditions inside an autoclave
Data Source
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AI summary
The present invention provides a closed composite material structure for aircraft fuselage shaped on a male jig from which it can be separated in a certain direction, said structure comprising a single outer panel and a plurality of inner longitudinal stiffeners integrated in said panel, such that the expansion coefficient of the male jig is greater than the expansion coefficient of the composite material of the structure, thus being able to remove the already manufactured structure, formed by the panel and the integrated inner stiffeners, in a single operation. The present invention further provides a process for manufacturing such a closed structure.