Rotatable Component Bonded Interface Stiffness Gradient

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Solution Overview

Problem

Rotatable components in machinery, such as gas turbine engines, face challenges in load distribution and stress concentration at perimeter areas, making mechanical interlock designs more reliable than bonded interfaces due to sensitivity to imperfections and stress concentrators.

Innovation Solution

A rotatable component with a bonded interface between sections of differing stiffness, where the load path is shifted away from perimeter areas by using a bonded interface design that includes a flange with non-uniform radial thickness to reduce tensile loads and distribute centrifugal forces effectively, allowing for the use of bonded interfaces over mechanical interlocks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a bonded interface is used between sections of a rotatable component, then ease of manufacture and flexibility are improved, but reliability deteriorates due to sensitivity to imperfections and stress concentrators at perimeter areas

Engineering Contradiction:
Improveease of manufactureVSAvoidreliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The flange is designed with non-uniform radial thickness, creating different stiffness characteristics in different regions. The varying thickness distributes stress more evenly across the bonded interface, reducing stress concentration at perimeter areas while maintaining the bonded connection's manufacturing advantages.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The radial thickness of the flange is varied as a design parameter to control stiffness and load distribution. By changing the thickness parameter across different regions of the flange, the design optimizes both the bonded interface performance and reliability, shifting the load path away from vulnerable perimeter areas.

Inventive Principle:
Principle #35Parameter changes

2Strength

If a flange with non-uniform radial thickness is used, then load distribution is improved and tensile loads are reduced, but device complexity increases

Engineering Contradiction:
ImprovestrengthVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The flange incorporates non-uniform radial thickness with varying stiffness in different regions to optimize load distribution. This local variation in geometric quality reduces tensile loads at critical areas while maintaining overall structural integrity, balancing strength enhancement with manageable complexity.

Inventive Principle:
Principle #3Local quality

3Reliability

If mechanical interlock design is used instead of bonded interface, then reliability is improved due to reduced sensitivity to imperfections, but ease of manufacture and flexibility deteriorate

Engineering Contradiction:
ImprovereliabilityVSAvoidease of manufacture
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The design replaces traditional mechanical interlock systems with a bonded interface connection. This substitution eliminates the complexity and potential failure points of mechanical keys and receivers while achieving comparable or superior reliability through the non-uniform flange design that manages stress distribution effectively.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution reduces the sensitivity to imperfections and stress concentrators, enabling the use of bonded interfaces in rotatable components, enhancing their reliability and durability by effectively managing load distribution and reducing tensile loads.

Implementation Method 1

distribute centrifugal forces effectively, allowing for the use of bonded interfaces over mechanical interlocks

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2589755B1Rotatable component of a gas turbine with controlled load interface and corresponding method
Publication Date: 2020.01.01 UNITED TECH CORP
  • EP2589755B1 patent drawingFigure 1
  • EP2589755B1 patent drawingFigure 2~5
  • EP2589755B1 patent drawingFigure 6A~7

AI summary

A rotatable component (50) includes a first section (52) and a second section (54) that is located radially outwards of the first section (52) with regard to an axis of rotation (A) about which the sections are co-rotatable. The sections (52, 54) are attached together at a bonded interface (56). At a perimeter region (60) of the bonded interface (56) a perimeter portion (52a) of the first section (52) has a first stiffness and a perimeter portion (54a) of the second section (54) has a second stiffness that is greater than the first stiffness.