Load-Sensing Strut With Segmented Sensing And Alleviation Members

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Solution Overview

Problem

Aircraft high-lift systems face challenges in accurately sensing structural disconnects within a specific loading range while maintaining high load carrying capability, requiring a load-sensing drive strut that is highly sensitive to incremental changes in low to moderate loads and capable of withstanding very high loads without malfunction.

Innovation Solution

A load-sensing strut with a load sensing member and a load alleviation member, where the load sensing member carries a greater portion of the load within a predetermined range and the load alleviation member engages at higher loads, featuring strain gauges and a non-linear loading scheme to enhance sensitivity and strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the drive strut is designed to carry very high loads (40-50 times the disconnect detection load), then the load carrying capability is improved, but the sensitivity to detect structural disconnects deteriorates

Engineering Contradiction:
Improveload carrying capabilityVSAvoidsensitivity to load changes
Core Design Contradiction:
StrengthVSMeasurement precision

Solution Approach 1:

The drive strut is segmented into two functional members: a load sensing member with high sensitivity to detect disconnect loads, and a load alleviation member that engages at high loads to protect the sensing member. This segmentation allows each member to be optimized for its specific function, resolving the contradiction between sensitivity and strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The load alleviation member acts as an intermediary that engages between the external high loads and the load sensing member. When high loads occur, the alleviation member carries the excess load, preventing it from overwhelming the sensitive sensing member, thus protecting the measurement precision while maintaining high load carrying capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the load sensing member carries all loads, then the measurement accuracy is improved, but the device complexity increases due to need for protective mechanisms

Engineering Contradiction:
Improveloading measurement accuracyVSAvoidstrut structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The load sensing member and load alleviation member are merged into a single integrated strut assembly with coordinated load paths. The sensing member is instrumented with strain gauges, and the alleviation member is structurally integrated through shared mounting features and load transfer paths, reducing overall device complexity compared to separate protective systems.

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 solution provides heightened sensitivity to incremental changes in low to moderate loads while maintaining high strength, allowing for early detection of structural disconnects and preventing further flap movement to mitigate damage.

Implementation Method 1

The load sensing member includes at least one load sensor generating a load signal

Methodology Applied
Scientific EffectStrain measurement: Deformation

Data Source

PatentEP2976224B1High sensitivity, load alleviating load sensor for strut application
Publication Date: 2018.04.18 MOOG INC
  • EP2976224B1 patent drawingFigure 1
  • EP2976224B1 patent drawingFigure 2
  • EP2976224B1 patent drawingFigure 3

AI summary

A load-sensing strut has a main body (26) having a longitudinal loading axis (A) along which an applied load is transmitted, and a load sensing member (38) arranged to carry at least a portion of the applied load when the load is within a predetermined range, wherein the load sensing member (38) includes at least one load sensor (46) generating a load signal.