Composite Saddle Clamp for Aircraft Fuel Tube Charge Dissipation

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Solution Overview

Problem

Existing saddle clamps used in aircraft fuel tanks face issues with friction-induced damage to tubing due to high vibrations, and they do not effectively dissipate electrostatic charges without compromising structural integrity.

Innovation Solution

A saddle clamp with monodispersed spherical aluminium particles dispersed in a thermoplastic polymer, providing both electrostatic charge dissipation and reduced friction through a metallic core, ensuring rigidity and consistent shape for secure tubing attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metallic inner parts are used in the clamp, then electrostatic charge dissipation is improved, but friction-induced damage to tubing increases due to high vibrations

Engineering Contradiction:
Improveelectrostatic charge dissipationVSAvoidfriction-induced damage to tubing
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The clamp is constructed as a composite material system with a polymer matrix containing dispersed metal particles (aluminium, copper, or nickel) at concentrations of 5-50 wt%. This composite structure provides both the electrical conductivity needed for electrostatic charge dissipation and the reduced friction characteristics of polymer materials, eliminating the harmful effects of metal-on-tubing friction while maintaining regulatory compliance for charge discharge paths.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the physical and chemical parameters of the clamp material by controlling metal particle concentration (5-50 wt%), particle size (1-100 micrometers), and polymer matrix composition. These parameter adjustments optimize the balance between electrical conductivity for charge dissipation and friction reduction, allowing the clamp to meet electrostatic discharge requirements while minimizing tubing damage from vibration-induced friction.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If polymer material is used in the clamp, then friction-induced damage to tubing is reduced, but electrostatic charge dissipation capability is insufficient

Engineering Contradiction:
Improvefriction-induced damage to tubingVSAvoidelectrostatic charge dissipation
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The clamp is constructed as a composite material system with a polymer matrix containing dispersed metal particles (aluminium, copper, or nickel) at concentrations of 5-50 wt%. This composite structure provides both the electrical conductivity needed for electrostatic charge dissipation and the reduced friction characteristics of polymer materials, eliminating the harmful effects of metal-on-tubing friction while maintaining regulatory compliance for charge discharge paths.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the physical and chemical parameters of the clamp material by controlling metal particle concentration (5-50 wt%), particle size (1-100 micrometers), and polymer matrix composition. These parameter adjustments optimize the balance between electrical conductivity for charge dissipation and friction reduction, allowing the clamp to meet electrostatic discharge requirements while minimizing tubing damage from vibration-induced friction.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If metal particles are added to polymer, then electrostatic charge dissipation is improved, but structural integrity and rigidity may be compromised

Engineering Contradiction:
Improveelectrostatic charge dissipationVSAvoidstructural integrity and rigidity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention changes the physical and chemical parameters of the clamp material by controlling metal particle concentration (5-50 wt%), particle size (1-100 micrometers), and polymer matrix composition. These parameter adjustments optimize the balance between electrical conductivity for charge dissipation and friction reduction, allowing the clamp to meet electrostatic discharge requirements while minimizing tubing damage from vibration-induced friction.

Inventive Principle:
Principle #35Parameter changes

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 clamp reduces friction-related damage to tubing and effectively dissipates electrostatic charges, maintaining structural integrity and compliance with regulatory discharge paths.

Implementation Method 1

The metallic inner parts 10 contact the tubing while holding the tubing within the elastomer cushion 12 and are electrically connected to the metallic end portions 14. Any electrostatic charges are discharged from the tubing 26 to the saddle clamp 24 and from the saddle clamp 24 to the PEEK bracket 20.

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

Any electrostatic charges are discharged from the tubing 26 to the saddle clamp 24 and from the saddle clamp 24 to the PEEK bracket 20. Finally, the electrostatic charges are discharged into the rib 22.

Methodology Applied
Scientific EffectElectrostatic discharge: Electrostatic Discharge

Implementation Method 3

The clamp comprises a metal core for rigidity

Methodology Applied
Scientific EffectStructural rigidity:

Implementation Method 4

Aircraft can undergo high vibration during operation. Such high vibration can cause damage to the tubing due to friction against the metallic parts of the clamp.

Methodology Applied
Scientific EffectFriction reduction: Friction

Data Source

PatentEP3988829B1clamp
Publication Date: 2025.08.06 AIRBUS CANADA LLP
  • EP3988829B1 patent drawingFigure 1~2
  • EP3988829B1 patent drawingFigure 3~4

AI summary

There is provided a clamp comprising a polymer (44) having metal particles (42) dispersed therein. The metal particles (42) can be made of aluminium. In one aspect, the clamp contains a metal core (40) for rigidity. One use of the clamp is within aircraft for holding fuel line tubing in place.