Sheet Metal Case Retaining Ring for Turbine Vibration Damping

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Solution Overview

Problem

Turbine engine inter-compressor cases formed from thin sheet metal are prone to vibrational excitations during operation, affecting engine performance and durability due to lack of effective damping mechanisms.

Innovation Solution

A sheet metal case with potential displacement locations and a retaining ring assembly that applies a biasing force against the case wall, either inwardly or outwardly, to dampen vibrations through frictional engagement, preventing resonance frequencies without attachment via welding or fasteners.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If thin sheet metal is used for the inter-compressor case, then the case weight is reduced and manufacturing is simplified, but the case becomes susceptible to vibrational excitations affecting engine operation and part durability

Engineering Contradiction:
Improvecase weightVSAvoidvibration resistance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent applies damping treatment selectively at identified displacement locations on the case rather than uniformly across the entire structure. This localized approach reduces overall weight while providing vibration control where most needed, resolving the contradiction between lightweight construction and vibration resistance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent modifies the physical parameters of the case at specific locations by adding damping treatments that change the vibrational characteristics without significantly altering the overall mass. This allows the thin sheet metal to maintain its lightweight advantage while gaining vibration resistance through parameter modification at critical locations.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If damping treatments are applied to reduce vibrations, then engine operation stability is improved, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvevibration stabilityVSAvoiddamping system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The damping system is segmented into discrete treatments applied at specific displacement locations rather than a continuous complex system. Each damping treatment is an independent, relatively simple element, allowing vibration stability to be achieved through multiple simple components rather than one complex system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The damping treatments are designed to be self-containing and self-explanatory, requiring minimal additional support structures or complex integration. Each treatment essentially serves itself by being applied directly to the case at the identified displacement location, reducing overall system complexity.

Inventive Principle:
Principle #25Self-service

3Strength

If traditional welding or fastening methods are used to attach damping components, then structural strength is improved, but manufacturing time and complexity increase

Engineering Contradiction:
Improveattachment strengthVSAvoidmanufacturing simplicity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces traditional mechanical attachment methods (welding, fastening) with alternative attachment mechanisms that achieve sufficient strength without the complexity of conventional joints. This substitution maintains adequate attachment strength while significantly simplifying the manufacturing process.

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

Solution Approach 2:

The attachment method parameters are changed from permanent, complex mechanical connections to simpler, potentially reversible attachments that provide sufficient strength for the application. This parameter change in the attachment approach maintains structural integrity while improving ease of manufacture.

Inventive Principle:
Principle #35Parameter changes

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

The solution effectively dampens vibrations at specific locations within the engine, enhancing engine performance and durability by targeting vibrational hotspots without increasing the case's stiffness or weight.

Implementation Method 1

biased against the case wall at the at least one potential displacement location

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

dampen vibrations through frictional engagement, preventing resonance frequencies

Methodology Applied
Scientific EffectVibration damping: Damping

Data Source

PatentEP4491854A1Sheet metal casing mechanical damping retaining ring
Publication Date: 2025.01.15 PRATT & WHITNEY CANADA CORP
  • EP4491854A1 patent drawingFigure 1
  • EP4491854A1 patent drawingFigure 2~5
  • EP4491854A1 patent drawingFigure 6~7

AI summary

A gas turbine engine (20) includes a compressor section (24), a combustor (26) and a turbine section (28). At least one case (30) surrounds at least one of the compressor section (24) and the turbine section (28). The case (30) is formed from sheet metal and includes a case wall (36) and at least one potential displacement location due to vibration. At least one retaining ring (32) is assembled to the case (30) and biased against the case wall at the at least one potential displacement location to dampen vibration by means of generating an inwardly directed compressive force (58).