Composite Gas Turbine Housing Flange Assembly via Thermal Expansion
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Solution Overview
Problem
The challenge lies in manufacturing a flange for composite material containment cases in gas turbine engines, where the complex shape makes it difficult to integrate the flange with the barrel using existing methods, often requiring mechanical fasteners for attachment.
Innovation Solution
A method involving a mould with a thermally-expandable unit forces the composite material into a sleeve's recess during curing, eliminating the need for mechanical fasteners by radially-outward thermal expansion, allowing for a seamless mechanical joint between the composite housing and sleeve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the flange is separately manufactured and then attached to the barrel after curing, then the complex shape of the flange can be achieved, but mechanical fasteners or bonding is required which increases assembly complexity and reduces structural integrity
Solution Approach 1:
The flange and barrel are merged into a single integrated composite structure manufactured in one curing cycle. The mould design allows both components to be formed simultaneously from the same composite material, eliminating the need for separate manufacturing and assembly operations. This integration resolves the contradiction by achieving both the complex flange shape and simplified assembly through design synthesis.
Solution Approach 2:
The flange is pre-formed within the mould during the barrel curing process before final assembly. The mould includes features that shape the flange geometry in advance, allowing the complex shape to be established during the laying-up and curing stages rather than requiring post-assembly operations. This preliminary formation eliminates the need for mechanical fasteners while maintaining structural integrity.
2Strength
If mechanical fasteners or bonding is used to attach the flange to the barrel, then the flange can be securely attached, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The attachment of flange to barrel is merged with the curing process itself. As the composite material cures, the flange and barrel become structurally integrated without requiring separate attachment operations. This eliminates the time required for mechanical fastening or bonding while maintaining strong structural connection through the continuous composite material.
Solution Approach 2:
The useful action of forming and attaching the flange to the barrel is made continuous through the curing process. The composite material remains in a workable state during laying-up and curing, allowing the flange to be formed and attached in one continuous operation rather than requiring interruption for separate attachment steps. This continuity eliminates idle time and simplifies the manufacturing process.
3Stability of the object's composition
If the flange is integrated with the barrel using composite material, then structural integrity is improved, but the manufacturing difficulty increases due to the complex shape
Solution Approach 1:
The mould acts as an intermediary tool that simplifies the manufacturing of the complex integrated flange-barrel structure. By designing the mould with appropriate features, the complex geometry is imposed on the composite material during laying-up, allowing the integrated structure to be formed easily without manual manipulation. The mould mediates between the desired complex shape and the manufacturing process, maintaining structural integrity while improving ease of manufacture.
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 enables the creation of a strong, uninterrupted mechanical joint around the full circumference without the need for bolts or adhesives, simplifying the manufacturing process and enhancing the structural integrity of composite components like containment cases.
Implementation Method 1
the thermally-expandable unit comprises a material having a coefficient of thermal expansion greater than that of the main body of the mould; before or during the curing step, the first portion of the composite material of the housing is forced into a recess of the sleeve by radially-outward thermal expansion of the thermally-expandable unit of the mould
Data Source
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AI summary
A structure such as a containment case (2) for a gas turbine engine (1) comprises an annular housing (3) made of composite material. A sleeve-like flange unit (4) is fitted onto an end of the housing (3) and is mechanically joined thereto by a first portion (31, 32, 33) of the composite material of the housing which projects into a recess (411) of the flange unit (4). This reduces or eliminates the need to use mechanical fasteners to connect the housing (3) to the flange unit (4).