Integrated Afterbody Mount Case for Gas Turbine Nacelle Load Isolation

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Solution Overview

Problem

Existing nacelle assemblies for gas turbine engines fail to effectively isolate and manage aerodynamic and backbone bending loads, leading to potential structural damage and vibration issues.

Innovation Solution

The integration of an afterbody mount case within the nacelle assembly, featuring an outer ring and radially extending spokes that distribute and absorb loads, isolating the turbine exhaust case from direct reaction loads and allowing for flexible movement to dampen vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the turbine exhaust case is directly connected to the pylon mounting structure, then the mounting structure can directly react loads, but the turbine exhaust case is subjected to high structural stress and vibration that can cause damage

Engineering Contradiction:
Improvestructural stress on turbine exhaust caseVSAvoidmounting structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

An afterbody mount case is introduced as an intermediary component between the turbine exhaust case and the pylon mounting structure. This afterbody mount case includes a first portion that couples to the turbine exhaust case and a second portion that couples to the pylon, thereby mediating the load transfer and protecting the turbine exhaust case from direct structural stress and vibration.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mounting structure is segmented into distinct functional portions: the turbine exhaust case, the afterbody mount case (with first and second portions), and the pylon. This segmentation allows each component to be optimized for its specific function, with the afterbody mount case specifically designed to absorb and dampen vibrations while transferring loads to the pylon.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If rigid mounting is used to securely attach the engine to the pylon, then structural stability is improved, but vibration transmission to the engine increases

Engineering Contradiction:
Improvestructural stabilityVSAvoidvibration transmission
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The afterbody mount case incorporates flexible or compliant mounting elements that allow for controlled movement and vibration absorption. These flexible connections maintain structural stability while reducing the transmission of harmful vibrations to the engine, effectively decoupling the rigid pylon structure from the sensitive engine components.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The afterbody mount case is designed with vibration-dampening features that provide beforehand cushioning against vibration transmission. By incorporating damping materials or compliant structures in advance, the system protects the engine from vibration damage before the vibrations can cause harm.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If the nacelle assembly uses separate components for mounting and housing, then ease of manufacture is improved, but the overall structural integrity and load management deteriorate

Engineering Contradiction:
Improvecomponent assemblyVSAvoidload isolation effectiveness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The afterbody mount case merges the mounting function and the housing function into a single integrated component. This merged structure maintains structural integrity and effective load isolation while simplifying the manufacturing process by reducing the number of separate parts that need to be assembled.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2562086B1Nacelle assembly having integrated afterbody mount case
Publication Date: 2018.07.11 UNITED TECH CORP
  • EP2562086B1 patent drawingFigure 1
  • EP2562086B1 patent drawingFigure 2
  • EP2562086B1 patent drawingFigure 3A~3B

AI summary

A nacelle assembly (35) for a gas turbine engine includes an integrated afterbody mount case (62). The integrated afterbody mount case (62) includes an outer ring (66) and a plurality of spokes (68) that extend radially inwardly from the outer ring (66). The outer ring (66) includes a radially outer surface (70) and a radially inner surface (72). The plurality of spokes (68) are circumferentially disposed about the radially inner surface (72) and extend radially inwardly from the radially inner surface (72).