Blading Member Mechanical Interlock for Thermal Stress Reduction
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Solution Overview
Problem
Existing blading member assembly techniques for fluid flow machines face challenges such as high thermal mismatch stresses, difficulty in reconditioning, and limitations in material choice due to rigid joining methods like brazing, and complex mechanical interlock mechanisms that are hard to service.
Innovation Solution
A blading member assembly using a mechanical interlock mechanism with a platform member and airfoil member, where the airfoil member has a foot section with a male mating section and a receiver section with interlock receiver recesses, allowing for differential thermal expansion and easy assembly/disassembly, using a retainer member to secure the interlock member, which can be made from different materials and manufactured through various processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If brazing is used to join airfoils and platforms, then rigid joining and structural strength are improved, but thermal mismatch stresses increase and reconditioning becomes difficult
Solution Approach 1:
The blading member is divided into separate airfoil members and platform members that can be independently manufactured, inspected, and reconditioned. The mechanical interlock system allows these segments to be disassembled and reassembled, facilitating reconditioning while maintaining structural integrity through the interlock mechanism and bearing surfaces.
2Strength
If brazing is used to join airfoils and platforms, then structural strength is improved, but thermal mismatch stresses increase
Solution Approach 1:
The mechanical interlock system acts as an intermediary between the airfoil and platform, providing a physical connection that does not rely on thermal bonding. This intermediate mechanical connection allows for differential thermal expansion without generating the high thermal mismatch stresses associated with brazing, while still providing sufficient joint strength through the interlock geometry and bearing surfaces.
3Shape
If mechanical interlock elements are completely received within the platform and accessible only from front sides, then structural compactness is improved, but servicing and reconditioning become extremely difficult
Solution Approach 1:
Instead of concealing the interlock mechanism within the platform structure, the invention inverts the approach by making the interlock members accessible from the airfoil side. The interlock members protrude from the airfoil and can be serviced, inspected, and removed from the airfoil end, reversing the accessibility problem while maintaining structural compactness through the interlock geometry.
4Stability of the object's composition
If curved retainer elements are completely received within the platform, then structural integration is improved, but removal for servicing becomes extremely difficult
Solution Approach 1:
The interlock members are extracted from the platform structure and instead protrude from the airfoil members. This extraction allows the interlock members to be independently accessed, removed, and serviced from the airfoil end without requiring disassembly of the platform structure, while the mechanical interlock geometry maintains structural integration and stability.
5Reliability
If extensive manufacturing steps including casting are used for interlock members, then connection reliability is improved, but material choice limitations increase
Solution Approach 1:
The invention changes the manufacturing parameters and methods for interlock members, moving from complex casting processes to simpler fabrication methods such as machining, forming, or additive manufacturing. These parameter changes enable the use of a broader range of materials including metals, polymers, and composites, while maintaining connection reliability through optimized interlock geometry and bearing surface design.
Data Source
AI summary
A blading member for fluid flow machines, for example, gas turbine engines. The blading member includes a platform member, at least one airfoil member, and at least one interlock member.