Pivotable Airfoil Root Mount for Gas Turbine Stress Reduction
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Solution Overview
Problem
Existing gas turbine engines face challenges in efficiently attaching and securing airfoils, which can lead to stress concentrations, increased maintenance complexity, and potential failures due to impacts from foreign object debris (FOD).
Innovation Solution
The proposed solution involves a novel airfoil assembly and mounting system for gas turbine engines, where airfoils are pivotally mounted to the hub using a root mount with hinge joint arrangements and damping members. This design reduces stress concentrations, simplifies installation and maintenance, and incorporates composite materials to minimize weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If airfoils are rigidly mounted to the hub, then structural strength is improved, but stress concentrations increase and reliability decreases
Solution Approach 1:
The airfoil mounting system transitions from a rigid fixed connection to a dynamic pivotable connection through the hinge joint arrangement. The airfoil can rotate about a hinge line within the slot, allowing movement that accommodates FOD impacts and reduces stress concentrations while maintaining structural strength through the root mount and damping members.
Solution Approach 2:
The damping members are positioned between the airfoil root section and the hub to provide beforehand cushioning against FOD impacts. These damping members absorb impact energy before it reaches the airfoil-hub attachment points, reducing stress concentrations and preventing failure while maintaining structural integrity.
2Reliability
If complex mounting arrangements are used to secure airfoils, then reliability is improved, but device complexity and maintenance difficulty increase
Solution Approach 1:
The mounting system is segmented into distinct functional components: the root mount with hinge joint arrangement for pivoting, the slot in the hub for guiding movement, and the damping members for impact absorption. This segmentation allows each component to perform its specific function independently, simplifying the overall system while maintaining reliability.
Solution Approach 2:
The pivotable connection through the hinge joint arrangement simplifies the mounting system by allowing the airfoil to move dynamically within the slot rather than requiring complex fixed securing mechanisms. This dynamic capability maintains reliability while reducing device complexity and ease of maintenance.
3Ease of manufacture
If traditional mounting systems are used, then ease of manufacture is maintained, but stress concentrations lead to potential failures
Solution Approach 1:
The damping members are incorporated into the manufacturing process to provide beforehand cushioning against FOD impacts. These members are positioned between the airfoil root section and the hub during assembly, absorbing impact energy before it reaches critical attachment points and preventing failure while maintaining ease of manufacture.
Solution Approach 2:
The hinge joint arrangement with pivotable airfoil connection is integrated into the manufacturing process, allowing the airfoil to be mounted in a controlled manner within the slot. This dynamic mounting capability enhances reliability by accommodating impact forces while maintaining compatibility with traditional manufacturing processes.
Data Source
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AI summary
An airfoil assembly (164) for a gas turbine engine (20) according to an example of the present disclosure includes, among other things, an airfoil including an airfoil section (168) extending from a root section (170). The airfoil section (168) extends between a leading edge (168L) and a trailing edge (168T) in a chordwise direction and extending between a tip portion (172) and the root section (170) in a radial direction. The airfoil section (168) defines a pressure side (168P) and a suction side (168S) separated in a circumferential direction. A root mount (178) includes first and second mount members (180, 182) secured to circumferentially opposed sides of the root section (170). Arcuate circumferential faces (180C, 182C) of the first and second mount members (180, 182) are dimensioned to pivotably mount the root section (170) to a hub (66) in an installed position. A method of assembly is also disclosed.