Hybrid CMC Rotor Disk Assembly with Non-Linear Hub
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Solution Overview
Problem
The challenge lies in manufacturing rotor disk assemblies for gas turbine engines using ceramic matrix composite (CMC) materials, as traditional methods like firtree slot arrangements and bolt fastening, effective with metal alloys, are not suitable for CMCs, leading to issues with stress balance and structural integrity in oxidizing gas flow environments.
Innovation Solution
A hybrid CMC rotor disk assembly is designed, combining metal alloys and CMC materials, featuring a hub with a non-linear bore and airfoil pin configuration that balances hoop stresses and minimizes free ring growth, utilizing a combination of materials like INCO718 and SiC/SiC for the hub, airfoils, and platform segments to create a stable and lightweight structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional metal alloy manufacturing methods (firtree slot arrangement, bolt fastening) are used for rotor disks, then structural integrity is maintained, but the design is not suitable for CMC materials and causes stress imbalance
Solution Approach 1:
The patent changes the geometric parameters of the hub bore from traditional linear designs to non-linear configurations specifically optimized for CMC rotor disks. This includes modifying the bore shape and airfoil pin arrangement to achieve proper stress distribution in CMC materials, resolving the contradiction between adapting to new materials and maintaining structural integrity
Solution Approach 2:
The patent employs hybrid composite material construction, combining metal alloy hub components with CMC rotor disk materials. This allows the hub to be manufactured with materials suitable for machining (metal alloys) while the rotor disk utilizes CMC properties, enabling both adaptability to CMC and maintenance of structural integrity through compatible joining methods
2Weight of moving object
If CMC materials are used for rotor disks, then weight is reduced and high temperature resistance is improved, but traditional fastening methods are not suitable
Solution Approach 1:
The patent extracts the fastening function from traditional bolt connections and integrates it into the hub structure itself through airfoil pins and specialized bore configurations. This eliminates the need for separate fastening components that would be incompatible with CMC materials, enabling weight reduction while maintaining ease of manufacture through simplified assembly
Solution Approach 2:
The patent introduces airfoil pins as intermediary components that facilitate the connection between the metal hub and CMC rotor disk. These pins serve as mediators that can be manufactured with materials suitable for both metal and CMC interfaces, resolving the manufacturing compatibility issue while preserving the weight benefits of CMC materials
3Reliability
If non-linear bore and airfoil pin configuration are used, then stress balance is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by implementing non-linear bore configurations and airfoil pin arrangements only in specific critical regions of the hub where stress balance is needed for CMC rotor disks. The rest of the hub maintains traditional simple geometry, thus achieving stress balance without excessive overall manufacturing complexity
Data Source
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AI summary
A Ceramic Matrix Composite (CMC) platform for an airfoil (66C) of a gas turbine engine (20) includes a CMC platform segment (86,88) which at least partially defines an airfoil profile.