Turbine Engine Case Compliant Attachment for Load Dissipation

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Solution Overview

Problem

Current turbine engine case attachments are inadequate in managing excessively large dynamic loads during events like fan blade-out, leading to flight safety issues and the need for aircraft removal for repairs.

Innovation Solution

A turbine engine case assembly featuring a compliant attachment device, such as a spring or frangible leaf spring, coupled between mounts on the outer frame to dissipate and reduce load transfer to the airframe during extreme conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rigid attachment links are used to support the turbine engine case, then structural strength and stability are improved, but excessively large dynamic loads are transmitted to the airframe during extreme events

Engineering Contradiction:

Improvestructural strengthVSAvoidload transfer to airframe

Core Design Contradiction:

StrengthVSForce

Solution Approach 1:

The patent changes the mechanical properties of the attachment device from rigid to compliant, allowing it to deform elastically under extreme loads. This parameter change enables the attachment device to maintain structural support while limiting force transmission to the airframe through controlled deformation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The compliant attachment device acts as an intermediary element between the engine case and airframe. It absorbs and dissipates excessive dynamic loads through elastic deformation, preventing direct force transmission while maintaining the structural connection.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Force

If frangible attachment devices are used to limit load transfer, then force transmission to the airframe is reduced, but device complexity increases

Engineering Contradiction:

Improveload transfer to airframeVSAvoidattachment device complexity

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The patent employs frangible attachment devices designed to fail in a controlled manner under extreme loads. These devices are intentionally designed with limited life or single-use characteristics, sacrificing the attachment device itself to protect the more critical airframe structure.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The frangible attachment device is pre-designed with predetermined failure points that activate before excessive forces reach the airframe. This beforehand cushioning mechanism ensures that extreme loads are limited without requiring complex active control systems.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Stability of the object's composition

If the engine case is securely mounted to the airframe, then structural stability is improved, but resonance and vibration are amplified during extreme events

Engineering Contradiction:

Improvestructural stabilityVSAvoidresonance and vibration

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the dynamic characteristics of the mounting system by introducing compliant elements with specific elastic properties. These parameter changes allow the system to maintain stability under normal conditions while dissipating vibrational energy and reducing resonance amplification during extreme events.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The compliant attachment device converts the harmful effect of rigid mounting (resonance amplification) into a beneficial damping effect. The elastic deformation of the attachment device absorbs vibrational energy, transforming what would be harmful resonance into controlled, dissipative motion.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 compliant attachment device effectively reduces the magnitude of loads transferred to the airframe, enhancing flight safety by mitigating resonance and allowing for localized impact absorption, potentially reducing the need for immediate aircraft service removal.

Implementation Method 1

a compliant attachment device operably coupled to the case at the at least two mounts. In one embodiment, the compliant attachment device is a spring.

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

The compliant attachment device effectively reduces the magnitude of loads transferred to the airframe, enhancing flight safety by mitigating resonance

Methodology Applied

Scientific EffectDamping: Damping

Implementation Method 3

In one embodiment, the compliant attachment device is frangible. In one embodiment, the spring is a leaf spring.

Methodology Applied

Scientific EffectFracture Mechanics: Fracture Mechanics

Data Source

PatentUS10519863B2Turbine engine case attachment and a method of using the same

Publication Date: 2019.12.31 RTX CORP

AI summary

The present disclosure relates generally to a turbine engine case assembly, the turbine engine case assembly including a fan case including an outer frame encircling an axis, the outer frame including an outer frame exterior surface and an outer frame interior surface, at least two mounts disposed on the outer frame exterior surface, wherein the at least two mounts are circumferentially spaced along the outer frame exterior surface, and a compliant attachment device operably coupled to the at least two mounts.