Hydraulic Wing Coupling for Passive Flight Load Alleviation

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Solution Overview

Problem

Aircraft wings with large span widths face structural challenges due to heavy loads from maneuvers and gusts, requiring innovative solutions for load alleviation that are reliable, compact, and efficient.

Innovation Solution

A coupling device with a hydraulic system that includes a chamber, piston device, and pressure relief valves, allowing the second wing section to rotate relative to the first section when loads exceed a threshold, mimicking non-linear mechanical springs without their drawbacks, and enabling fast load alleviation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a large wing span is used to facilitate high fuel efficiency, then fuel efficiency is improved, but the wing structure becomes very heavy to carry the wing bending loads

Engineering Contradiction:
Improvefuel efficiencyVSAvoidwing structure weight
Core Design Contradiction:
Use of energy by moving objectVSWeight of moving object

Solution Approach 1:

The wing is divided into a first wing section and a second wing section that can rotate relative to each other. This segmentation allows the wing to maintain a large span for fuel efficiency while reducing the structural weight through the ability to alter configuration and distribute loads dynamically.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coupling device enables dynamic adjustment of the wing configuration by allowing the second wing section to rotate relative to the first wing section. This dynamic capability transforms the static heavy structure into an adaptive system that can optimize weight distribution and load carrying based on flight conditions.

Inventive Principle:
Principle #15Dynamics

2Strength

If a mechanical spring is used for passive flight load alleviation, then load alleviation is achieved, but the system suffers from fatigue and wear

Engineering Contradiction:
Improveload alleviation capabilityVSAvoidfatigue and wear resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent replaces the mechanical spring system with a hydraulic coupling device that uses fluid pressure to provide load alleviation. This substitution eliminates the contact and friction inherent in mechanical springs, thereby reducing fatigue and wear while maintaining the passive load alleviation function.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The coupling device employs a hydraulic system with fluid pathways and pressure relief valves to provide passive flight load alleviation. The hydraulic mechanism replaces mechanical spring elements, offering a more reliable solution resistant to fatigue and wear while achieving the same load reduction objective.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Stability of the object's composition

If a damping system is arranged between wing sections to hold them straight, then wing stability is improved, but the system complexity increases

Engineering Contradiction:
Improvewing stabilityVSAvoiddamping system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The coupling device merges multiple functions into a single integrated system: it provides damping to hold wing sections straight during normal operation, enables load alleviation through pressure relief valves, and allows configuration changes. This consolidation reduces overall system complexity compared to separate systems for each function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The coupling device serves multiple purposes: it acts as a damping system for wing stability, a load alleviation mechanism through pressure relief, and a configuration control system. This multi-functionality reduces the need for separate components, thereby simplifying the overall system while maintaining stability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If a hydraulic system is used instead of mechanical springs, then reliability is improved by reducing fatigue and wear, but the device complexity increases

Engineering Contradiction:
Improvefatigue and wear resistanceVSAvoidhydraulic system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical spring elements with a hydraulic coupling device to eliminate fatigue and wear associated with mechanical contact. While this introduces hydraulic components, it eliminates the need for mechanical springs, shock absorbers, and associated maintenance systems, ultimately reducing overall system complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The hydraulic system provides a more reliable alternative to mechanical springs by using fluid pressure instead of mechanical elasticity. The hydraulic coupling device with pressure relief valves offers a simpler, more reliable solution that eliminates the fatigue and wear problems inherent in mechanical spring systems.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 coupling device effectively alleviates excessive loads on aircraft wings, reducing structural stress and maintaining wing integrity while allowing for efficient fuel use and compact installation, with reduced risk of fatigue and wear compared to mechanical springs.

Implementation Method 1

The chamber (50) as well as the first fluid pathway (56) are constituted by the housing (36) such that the housing, the chamber and the first fluid pathway are a single element

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Implementation Method 2

The first pressure relief valve (60) blocks the first fluid pathway (56), if the pressure in the second portion (54) is smaller than a first relief pressure, and opens the first fluid pathway (56), if the pressure in the second portion (54) is greater than the first relief pressure

Methodology Applied
Scientific EffectPressure relief: Pressure Increase

Data Source

PatentEP3121115B1Coupling device for a wing assembly of an aircraft
Publication Date: 2021.09.01 AIRBUS OPERATIONS LTD
  • EP3121115B1 patent drawingFigure 1~2
  • EP3121115B1 patent drawingFigure 3~7
  • EP3121115B1 patent drawingFigure 4~5

AI summary

The invention relates to a coupling device (28) for supporting a first wing section (22) against a second wing section (24) of an aircraft (10), that is configured for passive flight load alleviation and comprises a housing (36) comprising a chamber (50), wherein the chamber (50) comprises a first portion (52) as well as a second portion (54) and is filled with a fluid, a piston device (42) movably arranged in the chamber (50), wherein the piston device (42) separates the first portion (52) from the second portion (54) in a fluid tight manner, a first fluid pathway (56) connecting the first portion (52) to the second portion (54), a first pressure relief valve (60) arranged in the first fluid pathway (56), wherein the first pressure relief valve (60) blocks the first fluid pathway (56), if the pressure in the second portion (54) is smaller than a first relief pressure and opens the first fluid pathway (56), if the pressure in the second portion (54) is greater than the first relief pressure. In addition, the coupling device (28) can be used to acutate the second wing section (24) against the first wing section (22).