Engine Mount Fail-Safe Lug Joint for Lower Dynamic Amplification

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Solution Overview

Problem

Existing waiting fail safe systems in gas turbine engine mounts do not effectively prevent engine movement due to vertical loads after primary link failure, leading to increased design loads and weight due to dynamic amplification factors.

Innovation Solution

A trigger system with a straight and arcuate portion, including an activating nub and locking catch, is integrated into the waiting fail safe lug, allowing the slider block to engage with the pin and prevent subsequent movement when the system is activated, thereby reducing dynamic amplification and maintaining load equilibrium.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the waiting fail safe system is designed to accommodate dynamic amplification factor, then the design load increases, but the weight of the engine mount system increases

Engineering Contradiction:
Improvewaiting fail safe capabilityVSAvoidengine mount weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The trigger system is activated in advance when the pin contacts the activating nub, causing the slider block to move to the engaged position before significant engine movement occurs. This preliminary action prevents the need to design for full dynamic amplification, reducing the required load capacity and weight of the waiting fail safe system

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If the waiting fail safe system allows engine movement after primary link failure, then the structure is simpler, but the impact force increases

Engineering Contradiction:
Improvewaiting fail safe system complexityVSAvoidimpact force
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The trigger system activates in advance upon pin contact with the activating nub, moving the slider block to engage with the pin before the engine can move significantly. This preliminary engagement prevents large displacements and the associated impact forces, while maintaining relatively simple system architecture

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If the trigger system engages the slider block with the pin, then subsequent movement is prevented, but the device complexity increases

Engineering Contradiction:
Improveengine position stabilityVSAvoidtrigger system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The trigger system is divided into distinct functional segments: the activating nub on the pin, the trigger mechanism with arcuate and straight portions, the slider block with notch, and the spring. This segmentation allows each component to perform its specific function independently, achieving stable engine positioning through a modular rather than monolithic complex system

Inventive Principle:
Principle #1Segmentation

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 reduces the dynamic amplification factor, decreases the design load, and prevents engine movement due to vertical loads, contributing to a lighter engine mount system while ensuring load path redundancy.

Implementation Method 1

a spring operatively connected at one end to the slider block and operatively connected at another end to an end wall of the channel

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2971679B1Engine mount waiting fail safe lug joint with reduced dynamic amplification factor
Publication Date: 2023.02.15 RTX CORP
  • EP2971679B1 patent drawingFigure 1~3
  • EP2971679B1 patent drawingFigure 4~5
  • EP2971679B1 patent drawingFigure 6~8

AI summary

An engine mount may include a clevis and a lug defining a hole therethrough. A pin may be joined to the clevis and may extend through the hole of the lug with the pin and the lug defining a clearance therebetween. A trigger system may be disposed on the lug and operatively associated with the pin.