Aircraft Turbine Casing Ovalization Prevention
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Solution Overview
Problem
The existing manufacturing processes for aircraft turbomachine fan casings, particularly those made of composite materials, suffer from deformation issues such as ovalization during extraction from the mold and subsequent machining and bonding stages, leading to assembly, manufacturing, mechanical, and aerodynamic problems.
Innovation Solution
A method involving two annular shaping rings placed inside the casing during the bonding operation of the abradable layer, which applies heat and pressure to maintain the nominal geometry, allowing for precise shaping and preventing ovalization without cluttering the interior space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If composite material manufacturing process is used, then weight is reduced and mechanical resistance is improved, but deformation and ovalization occur during extraction and subsequent operations
Solution Approach 1:
The patent applies preliminary action by pre-heating and pre-compressing the casing in the mold before extraction to reduce residual stresses and minimize deformation. The shaping tools are also positioned in advance to maintain geometry during subsequent operations.
Solution Approach 2:
The patent implements preliminary anti-action by applying counter-forces through shaping tools during bonding operations to prevent ovalization. The compression system applies radial pressure to counteract the tendency of the casing to deform during abradable layer bonding.
2Manufacturing precision
If shaping tools are added to prevent ovalization, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the shaping tool into multiple independent elements: shaping tools positioned in the mold, and additional shaping tools positioned inside the casing during bonding. This segmentation allows each tool to perform a specific function while maintaining overall simplicity.
Solution Approach 2:
The patent uses an intermediary compression system that applies radial pressure through the casing wall during bonding operations. This intermediary mechanism transfers force from the bonding system to the casing to maintain geometry without requiring complex internal tooling.
3Manufacturing precision
If multiple shaping operations are performed, then manufacturing precision is improved, but production time increases
Solution Approach 1:
The patent merges multiple shaping operations by integrating the shaping function into the existing bonding process. The shaping tools are positioned and activated during the bonding operation itself, combining geometry maintenance with the necessary heating and compression steps rather than requiring separate operations.
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 effectively limits ovalization during the manufacturing process, simplifying machining and assembly, enhancing mechanical and aerodynamic performance, and reducing overall cycle time by maintaining the nominal geometry without the need for custom adaptations.
Implementation Method 1
The resin is polymerized by keeping the two half-shells closed. Depending on the desired production rate, polymerization is carried out at room temperature or by heating.
Implementation Method 2
during which the casing is heated and compressed by means of a system present at least partly inside the casing
Implementation Method 3
during which the casing is heated and compressed by means of a system present at least partly inside the casing
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
Method for producing a casing (3) for an aircraft turbine engine, said casing comprising an annular shell (9) extending about an axis A and made of a composite material, an annular layer (4) comprising an abradable material arranged inside the shell and covering a first internal annular surface (9bb) of an intermediate section (9ab), the method comprising a step of bonding the layer to the first surface, in which the casing is heated and compressed by means of a system present at least in part inside the casing, the method being characterised in that, before the casing is heated and compressed, a shaping tool (10) is mounted inside the casing and consists of two rings (12, 14).