Composite Fastening Structure for Lightning Current Conduction
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Solution Overview
Problem
Existing fastening structures in composite materials, such as those used in aircraft, face challenges in preventing current concentration and spark generation at fasteners during lightning strikes or other current-generating situations, as currents often fail to flow effectively between layers, leading to spark formation.
Innovation Solution
A fastening structure comprising a first structural member with an electrically-conductive inner layer and a non-conductive outer layer, and a second structural member with an electrically-conductive surface in contact with the first, where a metallic fastener penetrates both surfaces, facilitating current flow within the conductive layers and reducing concentration at the fastener.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a fastener is used to join composite structural members, then the structural members are securely fastened, but current concentration occurs at the fastener leading to spark generation
Solution Approach 1:
An electrically conductive member is introduced as an intermediary between the first and second structural members. This conductive member provides a dedicated pathway for electrical current to flow between the members, preventing current concentration at the fastener while maintaining the mechanical fastening function. The conductive member acts as a mediator that separates the electrical conduction function from the mechanical fastening function.
Solution Approach 2:
The invention uses a composite structure combining electrically conductive materials (such as metal or conductive polymer layers) with composite structural members. The electrically conductive layer is integrated into the composite material system, creating a multi-functional composite structure that simultaneously provides mechanical strength and electrical conduction capabilities.
2Use of energy by moving object
If current flows across structural members during lightning strike, then electrical energy is transmitted, but current concentrates at the fastener causing harmful effects
Solution Approach 1:
The electrically conductive member serves as an intermediary pathway that guides current flow between structural members. By providing this dedicated conduction path, the system allows current to flow efficiently while preventing it from concentrating at the fastener, thereby eliminating spark generation. The intermediary conductive member controls the current flow path to achieve both energy transmission and safety.
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 effectively suppresses current concentration and spark generation by allowing currents to flow within the conductive layers, thereby reducing the risk of spark formation at the fastener, enhancing safety and reliability in applications like aircraft.
Implementation Method 1
a first structural member including a composite material, and having a first electrically-conductive surface that has electric conductivity; a second structural member having a second electrically-conductive surface, in which the second electrically-conductive surface is in contact with the first electrically-conductive surface and has electric conductivity
Data Source
AI summary
A fastening structure includes a first structural member, a second structural member, and a fastening member. The first structural member includes a composite material, and has a first electrically-conductive surface having electric conductivity. The second structural member has a second electrically-conductive surface. The second electrically-conductive surface is in contact with the first electrically-conductive surface and has electric conductivity. The fastening member penetrates the first electrically-conductive surface and the second electrically-conductive surface, and fastens the first structural member and the second structural member.