Integrated Additive Rub-Strip Casing for Lower Part Count
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Solution Overview
Problem
Conventional manufacturing techniques for attritable gas turbine engines are costly and complex, and the installation of rub strips is labor-intensive, increasing part count and complexity.
Innovation Solution
An integrated rub-strip is formed using additive manufacturing, composed of the same material as the casing, with features like keyholes and spars to elastically deform and reduce interaction with rotating blades, reducing part count and assembly time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional manufacturing techniques are used for attritable gas turbine engines, then durability and safety requirements are met, but manufacturing cost and complexity increase
Solution Approach 1:
The rub strip is merged with the casing to form a single integrated component. The rub strip is additively manufactured as part of the casing interior surface, eliminating the need for separate rub strip installation and reducing part count while maintaining the required abradable function for clearance control
Solution Approach 2:
The additive manufacturing process serves multiple functions: it creates the casing structure, forms the rub strip feature on the interior surface, and integrates the rub strip material as part of the casing material itself. This multi-functionality reduces manufacturing steps and assembly operations
2Manufacturing precision
If conventional rub strip installation methods are used, then clearance control is achieved, but part count and assembly labor increase
Solution Approach 1:
The rub strip and casing are merged into a single integrated component. The rub strip feature is formed directly on the casing interior surface through additive manufacturing, eliminating separate rub strip parts and their associated installation procedures while maintaining precise clearance control functionality
Solution Approach 2:
The rub strip feature is pre-formed as part of the casing during the additive manufacturing process. This preliminary formation of the rub strip eliminates subsequent installation steps and ensures precise positioning and integration with the casing structure from the outset
3Productivity
If additive manufacturing is used for the integrated rub strip, then part count and assembly time are reduced, but manufacturing process complexity increases
Solution Approach 1:
The additive manufacturing process is used to perform multiple functions simultaneously: creating the casing geometry, forming the rub strip feature on the interior surface, and selecting appropriate material properties for both the casing and rub strip. This consolidates multiple manufacturing operations into a single process step
4Strength
If separate rub strip material is applied to the casing, then abrasion resistance is achieved, but material cost and installation complexity increase
Solution Approach 1:
The rub strip is made from the same material as the casing, creating a homogeneous structure. This eliminates the need for separate rub strip materials and their associated costs, while the additive manufacturing process creates the appropriate material properties for abrasion resistance directly in the rub strip feature
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
The integrated rub-strip reduces part count, simplifies assembly, and lowers production costs while maintaining effective abrasion resistance.
Implementation Method 1
the keyhole structure is configured to elastically deform responsive to contact with the rotor
Implementation Method 2
The rub strip material is abraded by the rotating blade tips during operation
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A unitary rub strip comprises a casing having an inner surface and an outer surface opposite the inner surface; a unitary rub strip is formed integral with the casing proximate the inner surface, wherein the unitary rub strip comprises a modified structure within the casing configured to abrade responsive to an interaction with a rotating element.