Metallic Fan Blade Platform With Frangible Wings
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Solution Overview
Problem
Existing fan assemblies in gas turbine engines are prone to foreign object damage, and the integrally formed platforms can be costly and inefficient, limiting the rotation capability of fan blades and requiring large rotor disks to manage centrifugal loads.
Innovation Solution
A metallic fan platform with laterally and radially extending frangible wings is used between adjacent fan blades, providing a compact, easily manufactured, and inexpensive solution that maintains aerodynamic efficiency and allows for limited rotation of fan blades during extreme events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If integrally formed platforms are used with fan blades, then structural strength is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The platform is divided into a body portion and separate wing portions that can be independently manufactured and then assembled. This segmentation allows each component to be optimized separately and reduces manufacturing complexity while maintaining the overall structural strength of the integrated platform assembly.
Solution Approach 2:
The platform body and wings are combined into a single functional assembly that provides the necessary structural support. The separate components are designed to work together as a unified structure, achieving the structural strength of an integrally formed platform without the manufacturing complexity.
2Strength
If larger dovetails are used to carry centrifugal loads, then strength is improved, but the rotor disk size must increase
Solution Approach 1:
By segmenting the platform into body and wing portions, the centrifugal loads are distributed more efficiently across the rotor disk structure. This allows for smaller dovetail connections while maintaining the necessary strength to handle centrifugal forces.
Solution Approach 2:
The platform design optimizes material distribution locally, concentrating structural strength where needed in the body portion while using lighter wing portions that extend aerodynamically. This localized optimization reduces overall centrifugal loads on the rotor disk.
3Shape
If composite platforms are used, then aerodynamic efficiency is improved, but manufacturing cost increases
Solution Approach 1:
The platform uses metallic materials with optimized geometric parameters to achieve aerodynamic efficiency comparable to composite designs. The body and wing portions are shaped to minimize drag while maintaining structural integrity, providing a cost-effective alternative to composite construction.
Solution Approach 2:
The metallic platform design offers a more economical alternative to expensive composite platforms. While individual platforms may have limited service life, the lower manufacturing cost and ease of replacement make this a cost-effective solution for maintaining aerodynamic efficiency.
4Reliability
If frangible wings are added to the platform, then protection against foreign object damage is improved, but device complexity increases
Solution Approach 1:
The platform is segmented into a permanent body and frangible wings that can detach during foreign object impacts. This segmentation provides protection by allowing the wings to sacrificially break away, preventing damage to the main blade structure.
Solution Approach 2:
The frangible wings are designed to break away during foreign object impacts, converting the harmful impact force into a controlled detachment event. This sacrificial design protects the main platform body and blade from damage by allowing the wings to absorb and dissipate impact energy.
Data Source
AI summary
A platform is provided for use between adjacent fan blades joined to a rotor disk to provide an inner flowpath boundary. The platform includes: a metallic arcuate body with opposed forward and aft ends and opposed lateral edges; and a pair of frangible wings that extend from the lateral edges laterally and radially beyond the body.