Mechanical Fuse Mount for Gas Turbine Auxiliary Shock Loads

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Solution Overview

Problem

Conventional mounting systems for auxiliary components in gas turbine engines are unable to withstand high shock loads from events like fan blade outages, leading to potential separation or damage due to inadequate design to handle rotor imbalance loads.

Innovation Solution

A mounting assembly with a mechanical fuse that shears during an overload event, specifically designed to absorb lateral loads by incorporating a center portion with fuse members and wall members configured to fracture in a controlled manner, maintaining component positioning and absorbing energy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional mounting systems are designed to withstand high shock loads from fan blade out events, then the auxiliary components are protected from separation and damage, but the mounting system requires heavier and stronger materials that increase overall weight and reduce design flexibility

Engineering Contradiction:

Improvemounting system reliability under shock loadVSAvoidmounting system weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The mounting system is segmented into a permanent mounting structure and a detachable mechanical fuse component. The mechanical fuse acts as a separate, sacrificial element that can be replaced after activation, allowing the main mounting structure to remain lightweight while still providing shock load protection through the replaceable fuse component.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mechanical fuse is designed as a disposable or replaceable component that is intentionally weaker than the main mounting structure. During extreme shock events, the mechanical fuse activates and can be replaced, protecting the more critical and expensive auxiliary components while avoiding the need to over-engineer the entire mounting system with heavy materials.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Strength

If the mounting system is designed with high strength to withstand rotor imbalance loads, then auxiliary components remain securely mounted, but the auxiliary components themselves may be over-engineered and heavier than necessary for normal operation

Engineering Contradiction:

Improvemounting system strengthVSAvoidauxiliary component weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The mechanical fuse acts as a pre-designed weak point or cushion in the mounting system. It is intentionally designed to fail before the auxiliary components or main mounting structure do, providing beforehand protection by absorbing or redirecting extreme shock loads away from the auxiliary components, allowing them to be optimized for normal operating conditions rather than worst-case scenarios.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The mechanical fuse serves as an intermediary element between the shock load source and the auxiliary components. It intercepts and manages extreme loads through its activation mechanism, preventing these loads from being transmitted to the auxiliary components, thereby allowing the auxiliary components to be designed for normal operating loads only.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If mechanical fuses are incorporated into the gearbox mounting system to protect against fan blade out events, then the gearbox hardware does not need to be over-designed, but the mounting system complexity increases due to the additional fuse components

Engineering Contradiction:

Improvegearbox protection against FBOVSAvoidmounting system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The mechanical fuse functionality is merged with the mounting assembly structure itself rather than being a completely separate system. The fuse members are integrated into the mounting assembly in a way that provides protection functionality while maintaining a relatively simple overall structure that combines the mounting and protection functions in a unified design.

Inventive Principle:

Principle #5Merging (Combining)

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 mechanical fuse effectively absorbs and manages high shock loads, preventing damage to auxiliary components and maintaining their position during overload events, thus enhancing the durability and reliability of the mounting system.

Implementation Method 1

the mechanical fuse is configured to shear in reaction to a load applied in a lateral direction

Methodology Applied

Scientific EffectShear stress: Shear Stress

Implementation Method 2

the mechanical fuse disposed between the first flange and the second flange and configured to shear during an overload event

Methodology Applied

Scientific EffectFracture mechanics: Fracture Mechanics

Data Source

PatentUS12060835B2Laterally biased system for mounting auxiliary components to gas turbine engines

Publication Date: 2024.08.13 RTX CORP

AI summary

A mounting assembly for mounting an auxiliary component to an engine case of a gas turbine engine includes a first flange configured for attaching the mounting assembly to the engine case; a second flange configured for attaching the mounting assembly to the auxiliary component; and a mechanical fuse disposed between the first flange and the second flange and configured to shear during an overload event.