Frangible Airfoil Design for Gas Turbine Fan Cases

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Solution Overview

Problem

Existing gas turbine engine fan cases are heavy and inefficient due to their design to withstand adverse conditions, which increases the weight and reduces performance, and current frangible structures are costly and do not adequately address issues of fan rotor unbalance and blade liberation.

Innovation Solution

A frangible airfoil design with a first material substrate and a second material substrate that defines discrete volumes along the chordwise and spanwise dimensions, allowing for controlled failure and reduced load transfer, enabling lighter and more efficient fan cases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fan cases are designed to withstand impact from adverse engine conditions, then reliability is improved, but weight increases and performance reduces

Engineering Contradiction:

Improvefan case reliabilityVSAvoidfan case weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The airfoil is segmented into multiple materials with different properties - a first material substrate providing structural integrity and a second frangible material substrate creating discrete volumes that control failure modes. This segmentation allows the fan case to be lighter while maintaining reliability through controlled deformation patterns.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the material parameters of the airfoil by incorporating a second material substrate with different mechanical properties (frangible characteristics) within the first material substrate. This parameter change enables controlled failure at specific locations, reducing the need for heavy protective structures.

Inventive Principle:

Principle #35Parameter changes

2Force

If frangible structures such as honeycombs or trench-filler material are used to mitigate load transfer, then load transfer is reduced, but cost increases and fan case weight increases

Engineering Contradiction:

Improveload transferVSAvoidfan case weight

Core Design Contradiction:

ForceVSWeight of moving object

Solution Approach 1:

The invention merges the structural function of the airfoil with the load-mitigation function of frangible structures by integrating the second material substrate directly within the first material substrate. This eliminates the need for separate honeycomb or trench-filler structures, reducing weight and cost while maintaining load transfer mitigation.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The frangible second material substrate is placed locally within specific regions of the airfoil where controlled failure is desired, rather than using universal frangible structures throughout. This localized approach reduces overall weight while effectively mitigating load transfer at critical locations.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If traditional frangible structures are used, then cost is reduced, but fan case size and weight increase and efficiency reduces

Engineering Contradiction:

Improvemanufacturing costVSAvoidengine efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The invention changes the material composition parameters of the airfoil itself to include frangible characteristics, eliminating the need for separate cost-reducing frangible structures. This integrated approach maintains manufacturing cost effectiveness while improving engine efficiency through reduced weight and optimized geometry.

Inventive Principle:

Principle #35Parameter changes

4Reliability

If fan cases are designed to withstand extreme conditions, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improvefan case reliabilityVSAvoidfan case structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS10731470B2Frangible airfoil for a gas turbine engine

Publication Date: 2020.08.04 GENERAL ELECTRIC CO

AI summary

An airfoil defining a chordwise dimension, a spanwise dimension, a leading edge, a trailing edge, a root, and a tip, is generally provided. The airfoil includes a first material substrate defining a pressure side and a suction side. The first material substrate defines a plurality of discrete volumes extended from at least one of the pressure side or the suction side into the first material substrate. The plurality of discrete volumes is arranged at least partially along the chordwise dimension and a second material substrate different from the first material substrate is defined at least partially within the volume.