Gas Turbine Vane Strut Flexible Cable Coupling

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Solution Overview

Problem

Existing vane strut assemblies in gas turbine engines experience significant bending stress due to relative axial and radial deflections, leading to over-engineering and increased material usage to accommodate these stresses, which results in heavier and more costly components.

Innovation Solution

A vane strut assembly design utilizing a braided cable and nickel fittings to couple panels, replacing rigid pins, which accommodates bending loads without inducing moments in the panels, thereby reducing stress and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If rigid pins are used to connect panels, then circumferential deflection is controlled, but large bending stress is induced in the panels and pins

Engineering Contradiction:
Improvecircumferential deflection controlVSAvoidbending stress
Core Design Contradiction:
Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The patent replaces rigid pins with a flexible cable system that connects the panels. The cable acts as a flexible element that can accommodate relative axial and radial deflections between panels without inducing large bending moments, thus reducing bending stress while still controlling circumferential deflection.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention changes the mechanical properties of the connection element from rigid (pin) to flexible (cable). This parameter change allows the connection to accommodate deflections dynamically, transforming the stress distribution from high bending stress to lower tensile/compressive forces in the cable.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If additional material is added to hardware, then reliability is ensured, but weight and cost increase

Engineering Contradiction:
Improvehardware reliabilityVSAvoidcomponent weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the connection mechanism from rigid pins requiring over-design for bending moments to flexible cables that naturally accommodate deflections. This parameter change reduces the material requirements while maintaining reliability, as the cable system inherently handles the deflection loads without requiring excessive material for stiffness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The flexible cable system uses simpler, lighter materials compared to the over-engineered rigid pin assembly. The cable and fitting construction allows for lighter weight components that achieve the required reliability without the excess material needed for rigid connections.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Strength

If rigid pins are used to connect panels, then structural strength is maintained, but panel size must be larger to accommodate bending stress

Engineering Contradiction:
Improvestructural strengthVSAvoidpanel size
Core Design Contradiction:
StrengthVSArea of moving object

Solution Approach 1:

The flexible cable connection eliminates the need for large panel attachment areas required by rigid pins. The cable system applies forces at concentrated points without requiring large reinforced panels, allowing for smaller panel sizes while maintaining structural integrity through the flexible connection mechanism.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP3508699B1Low bending stress gas turbine exhaust vane strut
Publication Date: 2021.06.30 RTX CORP
  • EP3508699B1 patent drawingFigure 1
  • EP3508699B1 patent drawingFigure 2A
  • EP3508699B1 patent drawingFigure 2B

AI summary

A vane strut assembly (312) is disclosed. The vane strut assembly (312) may include a first panel (322a), a second panel (322b), and a coupling mechanism that couples the first panel (322a) and the second panel (322b) to one another. The coupling mechanism may include a first fitting (334a) that is attached to the first panel (322a), a second fitting (334b) that is attached to the second panel (322b), and a cable (330) disposed between the first fitting (334a) and the second fitting (334b).