Composite LSP Fastener Structure to Prevent Lightning Arcing
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Solution Overview
Problem
Lightning strike protection (LSP) layers in composite aircraft structures face challenges in ensuring consistent and effective dissipation of electrical current when interrupted by fasteners, leading to potential damage from sparking and plasma arcing.
Innovation Solution
A laminate structure comprising layers of fibre-reinforced composite material with an LSP layer and a connector that overlaps and is electrically connected to the LSP layer, forming a bore through the LSP layer and laminate, ensuring effective electrical connection and preventing sparking between the LSP layer and fasteners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the LSP layer is interrupted by fasteners, then the structural assembly is enabled, but the electrical current dissipation becomes inconsistent and ineffective
Solution Approach 1:
A connector is introduced as an intermediary component between the fastener and the LSP layer. The connector includes an LSP connection surface that overlaps with and is electrically connected to the LSP layer, ensuring continuous electrical current dissipation path even when the LSP layer is interrupted by the fastener bore.
2Ease of operation
If a bore is formed through the LSP layer for fasteners, then the fastening function is achieved, but sparking and plasma arcing may occur
Solution Approach 1:
The connector acts as a mediator that bridges the gap created by the bore through the LSP layer. The LSP connection surface of the connector maintains electrical continuity around the bore, preventing sparking and plasma arcing between the fastener and the LSP layer.
Solution Approach 2:
The connector is positioned and electrically connected to the LSP layer before the fastener is fully installed. This preliminary electrical connection ensures that the current dissipation path is established in advance, preventing harmful sparking during the fastening operation and subsequent lightning strike events.
3Reliability
If the LSP connection surface overlaps with the LSP layer, then electrical connection is improved, but the device complexity increases
Solution Approach 1:
The connector serves multiple functions: it provides the fastening function through the bore, and simultaneously provides electrical connection through the LSP connection surface that overlaps with the LSP layer. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity.
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 dissipates electrical current and prevents sparking, enhancing the longevity and structural integrity of the laminate during lightning strikes by ensuring a reliable electrical path, thus mitigating damage from lightning strikes.
Implementation Method 1
a connector comprising an LSP connection surface which overlaps with, and is electrically connected to, the inner or outer face of the LSP layer
Data Source
AI summary
A structure is disclosed including a laminate having layers of fibre-reinforced composite material; and a lightning-strike protection (LSP) layer. The LSP layer has an outer face and an inner face opposite to the outer face. A connector has an LSP connection surface which overlaps with, and is electrically connected to, the inner or outer face of the LSP layer. A bore passes through the LSP layer, the laminate and the connector. A fastener secures together the structure to a second structure. Therein the fastener is received in the bore and the connector electrically connects the LSP layer to the fastener.