Permeable Lightning Strike Protection Material for Composite Resin Infusion
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Solution Overview
Problem
Current methods for incorporating lightning strike protection (LSP) materials into composite parts, such as those used in aerospace, are labor-intensive and inefficient, particularly in resin infusion processes like VARTM, due to the delicacy and limited drapability of traditional conductive materials like expanded metal foil, which can lead to surface quality issues and increased manufacturing costs.
Innovation Solution
A permeable LSP material composed of a nonwoven veil with a porous conductive layer and a non-continuous resin distribution, allowing for automated placement and infusion processes like ATL and AFP, enhancing surface quality and providing protection against lightning strikes, electrostatic discharge, and electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional conductive materials like expanded metal foil are used for lightning strike protection, then protection effectiveness is achieved, but the materials have limited drapability and cause surface quality issues
Solution Approach 1:
The patent employs a porous conductive layer made of sintered metal particles that allows resin penetration while maintaining electrical conductivity. The porous structure enables the material to be more compliant and easier to drape over complex surfaces compared to traditional expanded metal foil, thereby improving surface quality while maintaining lightning strike protection effectiveness.
Solution Approach 2:
The patent creates a composite structure combining conductive metal particles with polymer resin to form a flexible conductive layer. This composite material integrates the electrical conductivity of metal with the drapability and surface conformity of polymer, resolving the contradiction between protection effectiveness and surface quality.
2Reliability
If traditional conductive materials are used in resin infusion processes, then lightning strike protection is provided, but the process becomes labor-intensive and inefficient
Solution Approach 1:
The porous conductive layer allows resin to permeate through it during automated resin infusion processes like VARTM, enabling integration of the LSP material into the manufacturing process itself. This eliminates separate manual installation steps and enables automated placement, significantly improving manufacturing efficiency while maintaining protection effectiveness.
Solution Approach 2:
The conductive layer serves multiple functions: it provides lightning strike protection, enables automated resin infusion through its porous structure, and can be integrated with reinforcement fabrics. This multi-functionality allows a single material to address multiple requirements, streamlining the manufacturing process and improving productivity.
3Reliability
If traditional conductive materials are used, then lightning strike protection is achieved, but manufacturing costs increase
Solution Approach 1:
The porous structure of the conductive layer enables resin infusion to occur through the material itself during manufacturing, eliminating the need for separate installation operations. This integration of functions reduces labor costs and manufacturing complexity, thereby reducing overall manufacturing costs while maintaining protection effectiveness.
Solution Approach 2:
The patent changes the physical parameters of the conductive material from solid expanded metal foil to sintered metal particles with porous structure. This parameter change fundamentally alters the material's processability and manufacturability, enabling automated production methods that reduce labor costs and improve ease of manufacture.
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 permeable LSP material facilitates faster, more efficient, and higher-quality manufacturing of composite parts by enabling automated placement and infusion, reducing labor and costs while ensuring effective protection against electrical and electromagnetic threats.
Implementation Method 1
The porous conductive layer allows liquid resin to pass through it
Implementation Method 2
The resin material adheres to one side of the nonwoven veil and to the porous conductive layer
Data Source
AI summary
A permeable LSP material that can be incorporated into a resin infusion process such as RTM and VaRTM. This permeable LSP material may be in the form of an elongated or continuous tape that can be used in an automated placement process such as ATL and AFP. In one embodiment, the permeable LSP material includes at least the following components: (a) a nonwoven veil of randomly arranged fibers; (b) a porous electrically conductive layer having openings through its thickness; and (c) a resin material distributed, in a non-continuous manner, throughout the nonwoven veil 11 and between the nonwoven veil and the porous conductive layer. The permeable LSP material can be brought into contact with a dry preform, followed by resin infusion and curing to form a hardened composite part having the LSP material integrated therein.