Annular Casing Fire-Resistant Layer Application Method
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Solution Overview
Problem
Current methods for producing annular casings for aircraft turbine engines using composite materials are inefficient due to the need for a fire-resistant layer over flammable resins, which are complex and time-consuming to implement.
Innovation Solution
A method involving a self-extinguishing resin pre-impregnated fabric strip with glass or carbon fibers oriented at 45° to facilitate easy application around the casing, covering the entire surface in a single pass, and using compaction rolls with foam layers to ensure contact and adhesion, while also addressing galvanic corrosion in composite/metal assemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fire-resistant layer is applied over flammable resin to meet certification specifications, then fire resistance is improved, but the process becomes complex and time-consuming
Solution Approach 1:
The patent merges the structural composite material and fire-resistant coating into a single integrated layer. The bi-functional material contains both structural resin (for mechanical strength) and fire-resistant particles (for fire protection) within the same coating layer, eliminating the need for separate structural and fire-resistant layers.
Solution Approach 2:
The invention uses a composite coating material consisting of a resin matrix reinforced with fire-resistant particles. This composite structure provides both the adhesion and flexibility of the resin and the fire resistance of the particles, achieving fire protection while maintaining process simplicity.
2Reliability
If a fire-resistant layer is applied over flammable resin to meet certification specifications, then fire resistance is improved, but production time increases
Solution Approach 1:
The patent merges the structural composite material and fire-resistant coating into a single integrated layer. The bi-functional material contains both structural resin (for mechanical strength) and fire-resistant particles (for fire protection) within the same coating layer, eliminating the need for separate structural and fire-resistant layers.
Solution Approach 2:
The fire-resistant particles are pre-mixed into the coating material before application. This preliminary preparation ensures that fire resistance is built-in from the start, eliminating the need for subsequent fire-resistant coating steps and reducing overall production time.
3Ease of operation
If fibres are oriented at 45° in the fabric strip, then ease of application and bubble-free coverage are improved, but manufacturing precision of the strip is more difficult to achieve
Solution Approach 1:
The patent changes the fibre orientation parameter from the conventional 0°/90° grid pattern to a 45° diagonal pattern. This parameter change allows the fabric to better conform to curved surfaces and eliminates air bubble formation during application, while the precision is maintained through standard weaving techniques.
Data Source
AI summary
Methods for producing an annular casing for an aircraft turbine engine are provided. The annular casing includes an annular body made from a composite material based on a first resin, and a fire-resistant outer layer which covers an external annular surface of the body and which is made from a composite material based on a self-extinguishing second resin. The method includes preparing a strip of a glass fabric preimpregnated with said second resin, this strip including woven fibres oriented in directions that are perpendicular to one another and inclined by an angle of approximately 45° with respect to the axis of elongation of the strip, and applying the strip to the external surface of the body so as to cover the entirety of this surface in a single pass of the strip around the body.