Printed Conductive Ink Bus Bars for Aircraft Heating Flexibility

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional resistive heating elements in aircraft structures face challenges in routing and attaching power due to cyclic flexure and high fatigue, which limits their ability to provide reliable heat and ice protection, especially in high-fatigue applications where added weight and rigidity are concerns.

Innovation Solution

A resistive heating circuit with a flexible bus bar printed using conductive ink, including silver particles in an epoxy resin, is conformally disposed onto a dielectric substrate, matching or exceeding the flexibility of the resistive heating element, and electrically connected through a conductive resin body to ensure reliable power transmission across structures subject to cyclic flexure and high fatigue.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional cabling, wiring, and metallic plates are used to provide power to resistive heating elements, then power transmission is achieved, but the system adds weight and suffers from fatigue limitations under cyclic flexure

Engineering Contradiction:
Improvepower transmission reliabilityVSAvoidweight of power transmission components
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the physical state and material properties of the power transmission component by using a printed conductive ink formulation that cures to form a flexible, lightweight bus bar. This transforms the traditional rigid metallic plate into a flexible polymer-based conductor with embedded conductive particles, fundamentally altering density, flexibility, and fatigue resistance parameters while maintaining electrical conductivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention employs a composite material system consisting of a polymer matrix (epoxy or polyurethane) combined with conductive particles (silver, copper, or nickel). This composite approach creates a material that combines the flexibility and fatigue resistance of polymers with the electrical conductivity of metals, resolving the contradiction between weight/reliability and power transmission capability

Inventive Principle:
Principle #40Composite materials

2Reliability

If rigid metallic plates are used as bus bars, then electrical conductivity is maintained, but the bus bar cannot accommodate cyclic flexure of the aircraft structure

Engineering Contradiction:
Improveflexibility under cyclic flexureVSAvoidfatigue resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent replaces rigid metallic bus bars with a flexible printed bus bar that behaves as a flexible thin film or shell. The printed conductive ink forms a thin, flexible layer that can conform to and flex with the aircraft structure without cracking or failing, directly addressing the fatigue resistance requirement through inherent flexibility

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention changes the mechanical parameters of the bus bar by transitioning from rigid metal to a flexible cured ink formulation. The cured ink achieves appropriate tensile strength, elongation, and flexural properties to match the substrate, enabling the bus bar to accommodate cyclic flexure while maintaining structural integrity and fatigue resistance

Inventive Principle:
Principle #35Parameter changes

3Weight of moving object

If printed conductive ink bus bars are used, then weight is reduced and flexibility is improved, but manufacturing precision and electrical conductivity must be maintained

Engineering Contradiction:
Improveweight of bus barVSAvoidelectrical conductivity and traceability
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

Solution Approach 1:

The patent replaces traditional mechanical electrical connection methods (screws, welds, mechanical fasteners) with a printed conductive pathway system. The conductive ink is deposited in precise patterns that create continuous electrical traces, substituting mechanical assembly with a integrated printed circuit approach that ensures consistent electrical conductivity and traceability while reducing weight

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

Solution Approach 2:

The invention controls and optimizes parameters of the printed conductive ink including particle concentration, ink viscosity, deposition thickness, and curing conditions to achieve the desired balance between flexibility, weight reduction, and electrical conductivity. These parameter changes ensure manufacturing precision is maintained while realizing the benefits of the printed bus bar

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 solution provides a lightweight, flexible, and robust resistive heating circuit that maintains reliable heat generation and ice protection by matching the flexibility of the bus bar with the resistive heating element, thereby addressing the limitations of conventional methods and ensuring consistent performance across high-fatigue applications.

Implementation Method 1

The conductive ink can include silver particles in an epoxy resin

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

Resistive heating elements, such as in aircraft, are commonly used to generate heat for comfort and for ice protection

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Data Source

PatentEP3641492B1Method of using printed highly flexible conductive ink bus bars to transfer power to heated components
Publication Date: 2023.04.12 GOODRICH CORP
  • EP3641492B1 patent drawingFigure 1~3
  • EP3641492B1 patent drawingFigure 4~5
  • EP3641492B1 patent drawingFigure 6

AI summary

A resistive heating circuit (100) for a heated or ice protected aircraft structure includes a flexible dielectric substrate (110), a resistive heating element (102) supported by the substrate, and a bus bar (104). The bus bar is electrically connected to the resistive heating element and includes a conductive ink (112) printed onto the substrate such that the bus bar and resistive heating element flex freely with the heated or ice protected aircraft structure. Heated or ice protected aircraft structures and methods of making resistive heating circuits for heated or ice protected aircraft structures are also described.