Avionics Chassis Composite Shielding Lightning Protection

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Solution Overview

Problem

Contemporary avionics chassis face challenges in balancing weight reduction with the need for effective electromagnetic interference shielding, heat dissipation, and lightning strike protection, especially as newer avionics generate more heat and operate at higher frequencies, leading to increased weight due to larger heat sinks.

Innovation Solution

The use of a composite material housing with a metallic layer for radio wave shielding and a metallic strip for lightning strike protection, combined with thermally conductive card rails and heat-dissipating fins, provides the necessary protection while reducing weight through optimized material thickness and density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If aluminum material is used for avionics chassis, then shielding, heat dissipating, and protection benefits are achieved, but weight increases

Engineering Contradiction:

Improveshielding and protection capabilityVSAvoidchassis weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent uses a composite structure combining aluminum alloy chassis with carbon fiber reinforced plastic (CFRP) panels. The aluminum chassis provides structural strength, EMI shielding, and heat dissipation, while the CFRP panels reduce overall weight and provide additional thermal insulation. This composite approach achieves weight reduction while maintaining or improving protection capabilities.

Inventive Principle:

Principle #40Composite materials

2Temperature

If heat sink size is increased to dissipate more heat, then heat dissipation capability improves, but weight increases

Engineering Contradiction:

Improveheat dissipation capabilityVSAvoidheat sink weight

Core Design Contradiction:

TemperatureVSWeight of moving object

Solution Approach 1:

The patent changes the material parameters by using high-thermal-conductivity materials such as aluminum nitride (AlN) or boron nitride (BN) thermal interface materials and heat spreaders. These materials have superior thermal conductivity compared to traditional heat sink materials, enabling more effective heat dissipation with reduced size and weight. The thermal management system uses optimized thermal pathways with materials having tailored thermal properties.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If metallic layer thickness is increased for radio wave shielding, then shielding effectiveness improves, but weight increases

Engineering Contradiction:

Improveradio wave attenuationVSAvoidshielding layer weight

Core Design Contradiction:

Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The patent implements localized EMI shielding by placing metallic shielding layers or conductive coatings only in specific areas where EMI protection is most critical, such as around high-frequency circuit boards or sensitive avionics components. Rather than applying uniform thick shielding across the entire chassis, the shielding is concentrated where needed, reducing overall weight while maintaining effective protection.

Inventive Principle:

Principle #3Local quality

4Power

If newer avionics with higher power density are used, then processing speed and frequency improve, but heat generation increases

Engineering Contradiction:

Improveprocessing powerVSAvoidheat generation

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

The patent introduces thermal interface materials and heat spreaders as intermediary components between the high-power-density avionics and the heat dissipation system. These intermediaries efficiently transfer heat from compact high-power components to larger heat dissipation surfaces, managing the thermal load generated by modern high-performance avionics without requiring proportional increases in cooling system size.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This solution achieves a substantial 40% weight reduction while maintaining the required shielding and protection capabilities, effectively addressing the thermal management and weight concerns of avionics chassis.

Implementation Method 1

a radio wave shield comprising a metallic layer provided on the housing, wherein the radio wave shield attenuates radio waves entering and leaving the interior

Methodology Applied

Scientific EffectElectromagnetic shielding: Absorption (EM radiation)

Implementation Method 2

a lightning strike conductive path comprising a metallic strip provided on the housing, wherein the lightning strike conductive path directs the current from a lightning strike away from the interior of the housing

Methodology Applied

Scientific EffectLightning strike conduction: Conduction (electrical)

Implementation Method 3

combined with thermally conductive card rails and heat-dissipating fins, provides the necessary protection while reducing weight

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS8222541B2Avionics chassis

Publication Date: 2012.07.17 GENERAL ELECTRIC CO

AI summary

An avionics chassis comprises a composite housing, a radio wave shield, and a lightning strike conductive path, wherein the radio wave shield attenuates electromagnetic interference entering and leaving the housing, and the lightning strike conductive path directs the current from a lightning strike away from an interior of the housing.