Composite Panel Grounding Spring for Aircraft Lightning Protection
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Solution Overview
Problem
Existing aircraft lightning strike protection systems with composite exterior panels require additional metal shields for grounding due to high electrical resistance, leading to increased maintenance and servicing costs and downtime.
Innovation Solution
A composite panel assembly with a spring mechanism that electrically couples a shield panel to a conductive frame, allowing for quick servicing and maintenance by providing an electrical ground path for lightning strikes, reducing the need for additional metal shields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If composite material exterior panels are used to reduce weight, then weight is reduced, but electrical conductivity decreases and electrical resistance increases
Solution Approach 1:
A conductive shield is introduced as an intermediary component between the composite exterior panel and the internal structure. This shield provides the necessary electrical conductivity and lightning protection that the composite material lacks, while allowing the exterior panel itself to remain lightweight composite material.
Solution Approach 2:
The solution employs a composite structure combining composite exterior panels with a metal conductive shield. This composite approach allows each material to fulfill its optimal function: the composite panel provides weight reduction and aerodynamic properties, while the metal shield provides electrical conductivity and lightning strike protection.
2Reliability
If a metal barrier shield is added to provide lightning protection, then electrical conductivity is improved, but device complexity increases
Solution Approach 1:
The conductive shield serves multiple functions simultaneously: it provides lightning strike protection, establishes electrical continuity across the fuselage, and acts as a grounding path. This multi-functionality reduces the need for additional separate components and simplifies the overall protection system.
Solution Approach 2:
The patent integrates the lightning protection function with the electrical grounding system by combining the conductive shield with the existing fuselage structure and bonding system. This merging of functions reduces component count and simplifies installation and maintenance procedures.
3Reliability
If additional metal shields are installed for grounding, then electrical coupling is improved, but maintenance time increases
Solution Approach 1:
The bonding system incorporates flexible bonding elements and spring-loaded connectors that maintain reliable electrical contact despite thermal expansion, vibration, and structural movement. This dynamic design ensures continuous electrical coupling without requiring frequent adjustment or maintenance.
Solution Approach 2:
The design anticipates potential contact issues by incorporating redundant bonding paths and self-adjusting mechanical bonds that compensate for manufacturing tolerances and structural deformation. This beforehand cushioning prevents electrical discontinuity before it occurs, reducing maintenance needs.
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
Enables rapid servicing and maintenance of aircraft components, reducing labor and downtime costs while effectively protecting against lightning strikes through the spring's electrical coupling mechanism.
Implementation Method 1
a spring extending from the frame... the spring being ramped relative to the shield and extending between (i) at least one of the frame or an electrically conductive component associated with the frame, and (ii) the shield to define an electrical coupling therebetween
Data Source
Figure 1
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AI summary
Methods and apparatus for lightning strike protection are disclosed. A disclosed example apparatus includes a frame (202, 203, 206) supporting an exterior panel (210), the exterior panel having a first side (222) that at least partially defines an exterior surface of a vehicle, a shield panel (218) placed at a second side (220) of the exterior panel opposite the first side, and a spring (214) extending from the frame at a first portion of the spring, a second portion of the spring being at least one of ramped or curved, the second portion contacting the shield panel to define an electrical coupling between the shield panel and an electrically conductive portion associated with the frame.