Composite Airfoil Roll Snubber Mitigates Stress Concentration
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Solution Overview
Problem
Turbine engines face challenges in withstanding high mechanical stresses, particularly in the airfoil components, due to extreme loading conditions such as ingestion of foreign materials.
Innovation Solution
A composite airfoil assembly with a dovetail portion and an airfoil portion is designed, featuring a core with an outer skin and a roll snubber. The dovetail portion is secured within a slot on a disk, with the roll snubber extending into the gap between the dovetail and the slot, preventing contact and stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If composite materials are used for airfoil components, then weight is reduced and strength-to-weight ratio is improved, but resistance to extreme loading and sudden forces deteriorates
Solution Approach 1:
A roll snubber is provided within the gap between the dovetail portion and the slot to prevent contact between the dovetail corner and the slot during rotation. The roll snubber acts as a cushioning element that absorbs sudden forces and extreme loading before they can reach the composite airfoil assembly, thereby protecting the weight-sensitive composite structure while maintaining reliability under extreme conditions
2Stability of the object's composition
If the dovetail portion is tightly fitted in the slot, then structural stability is improved, but stress concentration and risk of contact during rotation increases
Solution Approach 1:
The roll snubber serves as an intermediary element positioned within the gap between the dovetail portion and the slot. It mediates the interaction between these components by preventing direct contact while allowing the dovetail to remain substantially tightly fitted in the slot, thereby maintaining structural stability without causing stress concentration
Data Source
AI summary
A turbine engine having a disk and a composite airfoil assembly. The disk having a slot. The composite airfoil assembly having an airfoil portion, a dovetail portion, and a roll snubber. The dovetail portion having a radially inner surface. The roll snubber being provided on the radially inner surface. The radially inner surface spaced from the slot to define a gap therebetween.