Segmented Thrust Reverser Cascade Assembly Fabrication
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Solution Overview
Problem
Existing methods for fabricating thrust reverser cascades in aircraft jet engines face challenges such as excessive blockage due to complex interface geometries, thermal stresses from over-molding metal with thermoplastics, and difficulties in non-destructive inspection and post-cure machining, particularly with one-piece frames that require complicated tooling and cannot use steel tooling.
Innovation Solution
A method involving the separate formation of frame sections and turning vanes via processes like pultrusion or extrusion, allowing for non-destructive inspection, improved bonding with a bonding agent, and assembly using steel tooling, which eliminates the need for complicated tooling and enables easier machining and increased strength-to-weight ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If injection molded vane modules are used to form thrust reverser cascades, then the number of interfaces between frame sections and turning vanes is reduced, but excessive blockage occurs due to complicated interface geometries
Solution Approach 1:
The thrust reverser cascade is segmented into separate frame sections and turning vanes that are formed independently and then assembled together. This segmentation eliminates the blockage problems associated with complex monolithic interface geometries while maintaining structural integrity through simplified mating surfaces between discrete components.
2Device complexity
If thermoplastics are over-molded on metal to form thrust reverser cascades, then the need for handling multiple turning vanes is eliminated, but substantial thermal stresses occur
Solution Approach 1:
Instead of over-molding thermoplastics on metal as a monolithic structure, the invention segments the cascade into separate metal frame sections and turning vanes formed by different processes. This eliminates the thermal stress problems inherent in over-molding while still achieving integration through precise assembly of the segmented components.
3Device complexity
If one-piece frames are used in thrust reverser cascades, then the structure appears simplified, but complicated tooling is required that cannot use steel due to CTE differences
Solution Approach 1:
The one-piece frame is segmented into multiple discrete frame sections that can be manufactured using conventional steel tooling. Each section is formed independently without requiring complex tooling extraction mechanisms, thereby eliminating the CTE compatibility issues while maintaining structural simplicity through the assembled configuration.
4Device complexity
If one-piece frames are used in thrust reverser cascades, then the frame structure is integrated, but non-destructive inspection and post-cure machining become difficult
Solution Approach 1:
The integrated one-piece frame is divided into separate frame sections that can be individually inspected using non-destructive testing methods. This segmentation provides accessible surfaces and geometries for NDI while maintaining the overall integrated appearance and structural functionality of the assembled cascade.
5Device complexity
If one-piece frames are used in thrust reverser cascades, then the frame is structurally unified, but the overall width cannot easily be increased
Solution Approach 1:
The structurally unified one-piece frame is replaced with segmented frame sections that can be easily configured in different widths by adding or removing sections. This segmentation provides modular scalability while maintaining structural unity through the assembled configuration, allowing the cascade width to be adjusted for different engine sizes and applications.
Data Source
AI summary
A method of fabricating a thrust reverser cascade assembly including positioning a first frame section on an assembly fixture, positioning a first set of turning vanes on a first elongated stiffener of the first frame section, securing the first set of turning vanes to the elongated stiffener, positioning a second frame section on the assembly fixture adjacent to the first frame section such that the first set of turning vanes are between the elongated stiffeners of the first and second frame section, adding additional sets of turning vanes and frame sections, and fastening the frame sections together.