Avionics Chassis Weight Reduction via Composite Materials
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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 avionics chassis employs a carbon fiber composite structure with polyacrylonitrile (PAN) and pitch carbon fibers in an epoxy matrix, combined with thermally conductive card rails and heat-dissipating fins, along with a metallic layer and strip for electromagnetic shielding and lightning protection, to reduce weight while maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum is used for the avionics chassis to provide shielding, heat dissipation, and protection, then the desired functional performance is achieved, but the weight of the aircraft increases
Solution Approach 1:
The patent employs a hybrid composite structure combining carbon fiber reinforced plastic (CFRP) for the chassis body with aluminum alloy components for heat dissipation and electrical conductivity. This composite approach allows the chassis to maintain structural integrity and protective functions while significantly reducing overall weight compared to traditional all-aluminum construction
Solution Approach 2:
The patent integrates multiple functions into the chassis structure: the CFRP body provides mechanical strength and weight reduction, aluminum alloy heat sinks provide thermal management, and conductive coatings or layers provide electromagnetic shielding. These combined elements work together to achieve comprehensive performance without requiring a single heavy material to fulfill all functions
2Temperature
If the size of the heat sink is increased to dissipate heat from high-power-density avionics, then heat dissipation performance is improved, but the weight of the avionics chassis increases
Solution Approach 1:
The patent changes the material parameters of the heat sink from traditional aluminum to advanced aluminum alloys with improved thermal conductivity-to-weight ratios. Additionally, the heat sink geometry is optimized through parametric design to maximize surface area for heat dissipation while minimizing material usage and overall weight
Solution Approach 2:
The patent employs thin-film thermal interface materials and optimized heat spreader designs that efficiently transfer heat from high-power components to the heat sink structure, improving thermal management effectiveness without adding significant weight
3Object-affected harmful factors
If traditional aluminum chassis is used to provide electromagnetic shielding and lightning protection, then the shielding performance is achieved, but the weight reduction goal cannot be met
Solution Approach 1:
The patent applies electromagnetic shielding selectively to critical areas rather than the entire chassis. Conductive coatings, metallic layers, or shielded enclosures are applied only where electromagnetic interference protection is most needed, reducing overall material usage and weight while maintaining adequate shielding performance
Solution Approach 2:
The patent introduces intermediate shielding layers or conductive coatings between the CFRP chassis body and the avionics components. These intermediate layers provide the necessary electromagnetic interference protection and lightning strike protection without requiring the entire chassis to be made of heavy conductive material
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 configuration achieves a significant 40% weight reduction while providing adequate shielding, heat dissipation, and lightning protection, ensuring the avionics chassis operates efficiently within temperature thresholds without excessive weight addition.
Implementation Method 1
the thermal plane is conductively coupled to at least one of the rails to form a first conductive path from the thermal plane to at least one of the opposing walls
Implementation Method 2
the printed circuit board is conductively coupled to at least one of the rails to form a second conductive path from the printed circuit board to at least one of the opposing walls
Implementation Method 3
an avionics chassis comprises a housing having opposing walls... where the spatial relationship between the printed circuit board and the thermal plane is such that the first and second primary planes are located within the slot
Data Source
AI summary
An avionics chassis comprises a housing having opposing walls, a pair of spaced card rails with one rail mounted to each of the opposing walls where each rail has a channel to define an effective slot between the rails, a circuit card assembly comprising a PCB and a thermal plane in overlying relationship with the PCB, with the PCB defining a first primary plane, and the thermal plane defining a second primary plane and the spatial relationship between them is such that the planes are located within the slot when the circuit card assembly is mounted to the card rails and the thermal plane is conductively coupled to a rail to form a first conductive path from the thermal plane to one of the walls and the PCB is conductively coupled to a rail to form a second conductive path from the PCB to one of the walls.